All posts by Stephen Goodman

Introducing guidelines for network scanning

2025-11-25 Stephen Goodman

Post Syndicated from Stephen Goodman original https://aws.amazon.com/blogs/security/introducing-guidelines-for-network-scanning/

Amazon Web Services (AWS) is introducing guidelines for network scanning of customer workloads. By following these guidelines, conforming scanners will collect more accurate data, minimize abuse reports, and help improve the security of the internet for everyone.

Network scanning is a practice in modern IT environments that can be used for either legitimate security needs or abused for malicious activity. On the legitimate side, organizations conduct network scans to maintain accurate inventories of their assets, verify security configurations, and identify potential vulnerabilities or outdated software versions that require attention. Security teams, system administrators, and authorized third-party security researchers use scanning in their standard toolkit for collecting security posture data. However, scanning is also performed by threat actors attempting to enumerate systems, discover weaknesses, or gather intelligence for attacks. Distinguishing between legitimate scanning activity and potentially harmful reconnaissance is a constant challenge for security operations.

When software vulnerabilities are found through scanning a given system, it’s particularly important that the scanner is well-intentioned. If a software vulnerability is discovered and attacked by a threat actor, it could allow unauthorized access to an organization’s IT systems. Organizations must effectively manage their software vulnerabilities to protect themselves from ransomware, data theft, operational issues, and regulatory penalties. At the same time, the scale of known vulnerabilities is growing rapidly, at a rate of 21% per year for the past 10 years as reported in the NIST National Vulnerability Database.

With these factors at play, network scanners need to scan and manage the collected security data with care. There are a variety of parties interested in security data, and each group uses the data differently. If security data is discovered and abused by threat actors, then system compromises, ransomware, and denial of service can create disruption and costs for system owners. With the exponential growth of data centers and connected software workloads providing critical services across energy, manufacturing, healthcare, government, education, finance, and transportation sectors, the impact of security data in the wrong hands can have significant real-world consequences.

Multiple parties

Multiple parties have vested interests in security data, including at least the following groups:

Organizations want to understand their asset inventories and patch vulnerabilities quickly to protect their assets.
Program auditors want evidence that organizations have robust controls in place to manage their infrastructure.
Cyber insurance providers want risk evaluations of organizational security posture.
Investors performing due diligence want to understand the cyber risk profile of an organization.
Security researchers want to identify risks and notify organizations to take action.
Threat actors want to exploit unpatched vulnerabilities and weaknesses for unauthorized access.

The sensitive nature of security data creates a complex ecosystem of competing interests, where an organization must maintain different levels of data access for different parties.

Motivation for the guidelines

We’ve described both the legitimate and malicious uses of network scanning, and the different parties that have an interest in the resulting data. We’re introducing these guidelines because we need to protect our networks and our customers; and telling the difference between these parties is challenging. There’s no single standard for the identification of network scanners on the internet. As such, system owners and defenders often don’t know who is scanning their systems. Each system owner is independently responsible for managing identification of these different parties. Network scanners might use unique methods to identify themselves, such as reverse DNS, custom user agents, or dedicated network ranges. In the case of malicious actors, they might attempt to evade identification altogether. This degree of identity variance makes it difficult for system owners to know the motivation of parties performing network scanning.

To address this challenge, we’re introducing behavioral guidelines for network scanning. AWS seeks to provide network security for every customer; our goal is to screen out abusive scanning that doesn’t meet these guidelines. Parties that broadly network scan can follow these guidelines to receive more reliable data from AWS IP space. Organizations running on AWS receive a higher degree of assurance in their risk management.

When network scanning is managed according to these guidelines, it helps system owners strengthen their defenses and improve visibility across their digital ecosystem. For example, Amazon Inspector can detect software vulnerabilities and prioritize remediation efforts while conforming to these guidelines. Similarly, partners in AWS Marketplace use these guidelines to collect internet-wide signals and help organizations understand and manage cyber risk.

“When organizations have clear, data-driven visibility into their own security posture and that of their third parties, they can make faster, smarter decisions to reduce cyber risk across the ecosystem.” – Dave Casion, CTO, Bitsight

Of course, security works better together, so AWS customers can report abusive scanning to our Trust & Safety Center as type Network Activity > Port Scanning and Intrusion Attempts. Each report helps improve the collective protection against malicious use of security data.

The guidelines

To help ensure that legitimate network scanners can clearly differentiate themselves from threat actors, AWS offers the following guidance for scanning customer workloads. This guidance on network scanning complements the policies on penetration testing and vulnerability reporting. AWS reserves the right to limit or block traffic that appears non-compliant with these guidelines. A conforming scanner adheres to the following practices:

Observational

Perform no actions that attempt to create, modify, or delete resources or data on discovered endpoints.
Respect the integrity of targeted systems. Scans cause no degradation to system function and cause no change in system configuration.
Examples of non-mutating scanning include:
- Initiating and completing a TCP handshake
- Retrieving the banner from an SSH service

Identifiable

Provide transparency by publishing sources of scanning activity.
Implement a verifiable process for confirming the authenticity of scanning activities.
Examples of identifiable scanning include:
- Supporting reverse DNS lookups to one of your organization’s public DNS zones for scanning Ips.
- Publishing scanning IP ranges, organized by types of requests (such as service existence, vulnerability checks).
- If HTTP scanning, have meaningful content in user agent strings (such as names from your public DNS zones, URL for opt-out)

Cooperative

Limit scan rates to minimize impact on target systems.
Provide an opt-out mechanism for verified resource owners to request cessation of scanning activity.
Honor opt-out requests within a reasonable response period.
Examples of cooperative scanning include:
- Limit scanning to one service transaction per second per destination service.
- Respect site settings as expressed in robots.txt and security.txt and other such industry standards for expressing site owner intent.

Confidential

Maintain secure infrastructure and data handling practices as reflected by industry-standard certifications such as SOC2.
Ensure no unauthenticated or unauthorized access to collected scan data.
Implement user identification and verification processes.

See the full guidance on AWS.

What’s next?

As more network scanners follow this guidance, system owners will benefit from reduced risk to their confidentiality, integrity, and availability. Legitimate network scanners will send a clear signal of their intention and improve their visibility quality. With the constantly changing state of networking, we expect that this guidance will evolve along with technical controls over time. We look forward to input from customers, system owners, network scanners and others to continue improving security posture across AWS and the internet.

If you have feedback about this post, submit comments in the Comments section below or contact AWS Support.

How AWS improves active defense to empower customers

2025-06-17 Stephen Goodman

Post Syndicated from Stephen Goodman original https://aws.amazon.com/blogs/security/how-aws-improves-active-defense-to-empower-customers/

At AWS, security is the top priority, and today we’re excited to share work we’ve been doing towards our goal to make AWS the safest place to run any workload. In earlier posts on this blog, we shared details of our internal active defense systems, like MadPot (global honeypots), Mithra (domain graph neural network), and Sonaris (network mitigations). We’re still inventing new ways to improve the effectiveness of threat intelligence and automated response to detect and help prevent attacks. Today we’ll share advancements in active defense related to malware, software vulnerabilities, and AWS resource misconfigurations. Like the other posts we linked to, these are constantly improving capabilities that our customers get just for being on the AWS network. We’ll discuss these topics in more depth at re:inforce 2025 during Innovation Talk SEC302.

Stopping malware from spreading

Financially motivated threat actors try to gain access to a wide array of networked assets. The more resources they control, the more places they can hide, and the longer they can profit from their abusive operations. As such, threat actor malware often contains modules to scan for new targets, replicate binaries over the network, and then repeat. If left unchecked, such rapidly spreading behavior can lead to network congestion, service availability loss, and data destruction. We want to help prevent this behavior to the greatest degree possible.

One effective strategy we employ is identifying the threat actor’s key infrastructure where malware is centrally controlled. We use a variety of techniques to identify, verify, track, and disrupt threat infrastructure. Using network traffic logs, honeypot interactions, and malware samples from an array of sensor positions, we mitigate botnets, abusive proxies, and peer-to-peer malware. Over the past 12 months, AWS helped prevent over 4 million malware infection attempts across 315 thousand distinct Amazon Elastic Compute Cloud (Amazon EC2) instances. By protecting workloads from these malware infections, we not only protect our network and our customers, but also the broader internet from further malware expansion.

Advancements in threat hunting and mitigating software vulnerabilities

At Amazon, we’re proud to support software vulnerability research with programs for bug bounty, vulnerability disclosure, and open source contribution. We’ve also become a more active participant in the CVE process by becoming a CVE Numbering Authority (CNA) for the software and services provided by Amazon. Thanks to the public CVE database, we see vulnerability research accelerating as reported CVEs have grown by 21 percent year-over-year since 2013, with over 40 thousand CVEs published in 2024. This virtuous cycle of finding and resolving vulnerabilities improves cyber security over time, but AWS sees threat actors searching for unresolved vulnerabilities to gain unauthorized access to resources.

We’ve expanded MadPot and Sonaris to identify and stop a broader range of malicious vulnerability scanning and exploitation activity, protecting every AWS customer from vulnerability exposure. We’ve added hundreds of new detections and MadPot service emulations to identify real attacks. As we’ve expanded our visibility, we’ve continued blocking hundreds of millions of CVE exploit attempts daily across the AWS network.

As we’ve made these active defense systems better at stopping CVE exploit attacks, the total number of attacks has gone down by over 55 percent in the last 12 months, as shown in Figure 1. There are many factors outside our control in this observation, but we’re happy to see fewer CVE exploit attacks. This trend coincides with the detection, regionalization, latency, and guardrail improvements we’ve made in 2025. No system can block everything, so fewer exploit attempts mean less risk across a wide range of workloads.

Figure 1: Chart showing the decrease in global malicious vulnerability exploit attempts

This work to identify known exploits in the wild directly benefits users of vulnerability intelligence in Amazon Inspector, which provides an Amazon Inspector score for customers to prioritize where to spend security hardening resources. This includes the most recent date of observed exploitation attempts, the MITRE ATT&CK techniques associated with the exploit activity, and the industries targeted.

Protecting architectures built on AWS

AWS actively defends compute and network resources for our customers; we also defend the distinct AWS-native resources that customers rely on. AWS access key credentials are a critical resource that allow access to customer accounts. The AWS Identity and Access Management best practices share proven techniques for customers to keep their credentials from being abused. Through active defense, we do even more to help customers who haven’t yet adopted these best practices.

Each day, AWS helps prevent an average of 167 million malicious scanning connections seeking unintentionally exposed AWS access key pairs. In case access keys are discovered through other means, we’ve expanded our protection of customer-managed IAM credentials. When our threat intelligence analytics show that a customer-managed credential is known by a threat actor, we put mitigations in place to restrict access to highly privileged operations. We also send customized notifications to help customers identify how the credential was exposed. These efforts are paying off for our customers every day; the following response is a good example of what we hear regularly:

This is a key that we already rotated a few weeks ago based on another alarm from you. It turned out that the new rotated key happened to be in your second alarm to us. So it meant that the app that the key was linked to was still leaking it.

So on Monday we sat down with the dev team, found where the app was leaking some secrets from, we patched it, I rotated all the exposed secrets (it was more than the IAM key) and we plugged in the extra security in the app.

So thanks again for those alerts, they are very precious.
– AWS Customer

In a specific case of threat activity in November and December of 2024, customers reported ransomware activity against their objects in Amazon Simple Storage Service (Amazon S3) storage. We saw that these ransom threats were highly correlated with exposed customer-managed IAM keys. We applied quarantines to the exposed keys, taking care to make sure that normal customer operations could continue safely. We re-sent our proactive notifications to customers about keys that were likely exposed, because the risk of an attack was elevated. During this period, we worked together with customers to deactivate over 30 thousand exposed credentials. Since this threat activity began, AWS has helped prevent over 943 million malicious attempts to encrypt customer Amazon S3 objects.

These credential exposure detections flow into Amazon GuardDuty Extended Threat Detection, simplifying threat detection and response operations for modern cloud environments.

Better together

The approach AWS takes to active defense shows how security can be improved by layering protections across the infrastructure stack and using threat intelligence to drive risk reduction. By building active defense into our services at no extra cost, AWS helps our customers stay protected from a wide range of threats.

While we continue to constantly improve our protections for our customers, some of our work is by nature probabilistic, because we never see inside customer workloads. We don’t apply active defense in situations where the detection is ambiguous, because that might impact our customers’ production systems. To stay secure, customers should never let down their own defenses. AWS security services like AWS Identity and Access Management (IAM), AWS Shield Advanced, AWS WAF, AWS Network Firewall, Amazon GuardDuty, and Amazon Inspector provide prevention, detection, and response that customers can configure for their unique needs. The good news is that by working together, we’re making the internet safer for everyone.

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