Tag Archives: Malware

Malware Campaign Lures Users With Fake W2 Form

Post Syndicated from Tom Elkins original https://blog.rapid7.com/2024/07/24/malware-campaign-lures-users-with-fake-w2-form/

Malware Campaign Lures Users With Fake W2 Form

Rapid7 has recently observed an ongoing campaign targeting users searching for W2 forms using the Microsoft search engine Bing. Users are subsequently directed to a fake IRS website, enticing them to download their W2 form that ultimately downloads a malicious JavaScript (JS) file instead. The JS file, when executed, downloads and executes a Microsoft Software Installer (MSI) package which in turn drops and executes a Dynamic Link Library (DLL) containing the Brute Ratel Badger.

In this blog, we will detail the attack chain and offer preventative measures to help protect users.


Starting on June 21, 2024, Rapid7 observed two separate incidents in which users downloaded and executed suspicious JavaScript (JS) files linked to the URL hxxps://grupotefex[.]com/forms-pubs/about-form-w-2/. Following execution of the JS files, Rapid7 observed the download and execution of an MSI file that was responsible for dropping a suspicious DLL into the user’s AppData/Roaming/ profile. Upon further analysis, Rapid7 determined that the suspicious DLL contained a Brute Ratel Badger. Brute Ratel is a command and control framework used for red team and adversary simulation.

When executed successfully, the Brute Ratel Badger will subsequently download and inject the Latrodectus malware. Latrodectus is a stealthy backdoor used by threat actors to query information about the compromised machine, execute remote commands, and download and execute additional payloads.

On June 23, Zscaler ThreatLabz issued a tweet indicating that the initial access broker behind the deployment of the malware family known as Latrodectus was using Brute Ratel as a stager.

On June 24, a blog was released by reveng.ai, outlining an identical attack chain that we observed. From the posts, we noted overlapping indicators of compromise (IOC), indicating that the behavior observed was related.

Initial Access:

During analysis of the incidents, Rapid7 observed that users queried the search engine Bing containing the key words W2 form. They subsequently navigated to the domain appointopia[.]com, which re-directed the browser to the URL hxxps://grupotefex[.]com/forms-pubs/about-form-w-2/.

After replicating the incident in a controlled environment, we observed that following the query for w2 form 2024 using Bing, the top result is a link to the domain appointopia[.]com which claims to have W2 forms available for download.

Malware Campaign Lures Users With Fake W2 Form
Figure 1 – Search Result for `w2 form 2024` Using Bing

After clicking the link, the browser is directed to the URL `hxxps://grupotefex[.]com/forms-pubs/about-form-w-2/`, which presents users with a fake IRS site, luring users into downloading their W2 form.

Malware Campaign Lures Users With Fake W2 Form
Figure 2 – Fake IRS Website

While interacting with the hyperlinks present on the website, we observed that each time, a CAPTCHA would appear, luring the users to solve it.

Upon closer examination, users were presented with a CAPTCHA system, seemingly designed to verify human activity. However, this CAPTCHA was part of a malicious scheme. Once answered successfully, the CAPTCHA would download a malicious JavaScript file named `form_ver`, appending the file name with the UTC time of access, such as `Form_Ver-14-00-21`. The source of the downloaded JS file came from a Google Firebase URL, `hxxps://firebasestorage.googleapis[.]com/v0/b/namo-426715.appspot.com/o/KB9NQzOsws/Form_Ver-14-00-21.js?alt=media&token=dd7d4363-5441-4b14-af8c-1cb584f829c7`. This JavaScript file would then be responsible for downloading the next stage payload.

Malware Campaign Lures Users With Fake W2 Form
Figure 3 – Sample CAPTCHA to Solve on `hxxps://grupotefex[.]com/forms-pubs/about-form-w-2/`

Technical analysis:

We acquired one of the JS files from the incidents that took place on June 21 and analyzed the contents in a controlled environment. We observed that the JS file contained code hidden between commented out lines. Threat actors employ this technique in order to inflate the size of their files and obfuscate their code with the goal of evading antivirus solutions and hindering reversing.

In addition, we observed that the JavaScript contained a valid Authenticode certificate issued to Brass Door Design Build Inc. Threat actors will embed valid certificates in order to exploit trust mechanisms and make the scripts appear legitimate.

Malware Campaign Lures Users With Fake W2 Form
Figure 4 – File Details for JS File `Form_ver-14-00-21.js`

We analyzed the JS files and observed code resembling a technique used for extracting and executing hidden code within comments. Specifically: The code defines a ScriptHandler class that can read in a script file, parse out any lines starting with `//////`, and store those lines of code in an extractedCode property as seen in Figure 5. The code then defines a method `runExtractedCode()` that executes that extracted code using new `Function()`. It instantiates a ScriptHandler for the current script file, extracts the hidden code, and executes it.

This allows hiding arbitrary code within comments in a script, which will then be extracted and executed when the script is run. The comments provide a way to conceal the hidden code. This technique was used to hide malicious code within a script file designed to make the user think it is benign. When the script is executed, the concealed code would be extracted and run without the user’s knowledge.

Malware Campaign Lures Users With Fake W2 Form
Figure 5 – First Part of Code from `Form_ver-14-00-21.js`

After cleaning up the script file, we observed that the purpose of the script was to download an MSI package from the URL `hxxp://85.208.108[.]63/BST.msi` and execute it.

Malware Campaign Lures Users With Fake W2 Form
Figure 6 – Cleaned Up Contents of `Form_ver-14-00-21.js`

In another related incident that occurred on June 25, we observed that the JS file was downloading the payload from a similar URL, `hxxp://85.208.108[.]30/neuro.msi`.

MSI Analysis

We acquired the latest MSI file, neuro.msi, from hxxp://85.208.108[.]30/neuro.msi and analyzed the contents. We observed that the contents of the MSI file contained a Cabinet (.cab) file named disk1.cab which stored a DLL, capisp.dll.

Malware Campaign Lures Users With Fake W2 Form
Figure 7 – Contents of MSI File `neuro.msi`

We also observed that the MSI package `neuro.msi` contained a custom action whose function was to drop the DLL, `capisp.dll`,  within AppData/Roaming/ folder and execute it using `rundll32.exe` with the export `remi`.

Malware Campaign Lures Users With Fake W2 Form
Figure 8 – MSI Log File Showing Installation and Execution of DLL `capisp.dll`

We obtained the DLL from the MSI installer and analyzed the contents.

Capisp.dll Analysis

During initial analysis, we observed the DLL was associated with the VLC media player. We also observed that the DLL contained a suspicious resource named نالوقتمتأخر located at the offset of 0x00EB2C0. We determined that the resource name نالوقتمتأخر was Arabic and translates to ‘It is late’, referring to time.

Malware Campaign Lures Users With Fake W2 Form
Figure 9 – Suspicious Resource Name

While analyzing the export function `remi` we observed that the function starts by storing a hardcoded string `)5Nmw*CP>sC%dh!E(eT6d$vp<)`, which is reserved for later use. The function then calculates the resource located at offset (0x00EB2C0) that marks the start of the encrypted data, which will be decrypted using an XOR decryption routine with the previously stored string.

Malware Campaign Lures Users With Fake W2 Form
Figure 10 – Snippet of Code Contained Within `capisp.dll`

After the data is decrypted, the function then utilizes the Windows API `VirtualAlloc` to allocate a new region of memory in order to copy and store the decrypted data.

Using that logic, we replicated the process in Cyberchef and observed that the decrypted data resembled another Windows binary. While analyzing the new binary, we observed an interesting string, `badge\_x64_rtl.bin.packed.dll`. We also observed that the new binary contained yet another embedded binary.

Further analysis revealed that the purpose of the decrypted binary was to load and execute the embedded binary. We identified the embedded binary as a Brute Ratel Badger (BRC4), a remote access agent in Brute Ratel. Upon successful execution, the BRC4 program attempts to establish connections to three hard coded Command and Control (C2) domains:




In previous versions of the attack, we observed the BRC4 program attempting to establish communication with the C2 domains `barsen[.]monster` and `kurvabbr[.]pw`.

Following execution of the BRC4 program, we observed the download of `Latrodectus` which was subsequently injected into the Explorer.exe process.

Malware Campaign Lures Users With Fake W2 Form
Figure 11 – Injection of Latrodectus Malware into Explorer.exe

We observed that the Latrodectus malware attempts to contact the following URLs:

* hxxps://meakdgahup[.]com/live/

* hxxps://riscoarchez[.]com/live/

* hxxps://jucemaster[.]space/live/

* hxxps://finjuiceer[.]com/live/

* hxxps://trymeakafr[.]com/live/


Rapid7 has observed a recent campaign targeting users searching for W2 forms. The campaign lures users into downloading JS files masqueraded as supposed W2 forms from a fake IRS website. Once the JS files are executed, it downloads and executes MSI packages containing the Brute Ratel badger. Upon successful compromise, the threat actors follow up by deploying the malware family known as Latrodectus, a malicious loader that is used by threat actors to gain a foothold on compromised devices and deploy additional malware.

Mitigation guidance:

➔ Provide user awareness training that’s aimed at informing users on how to identify such threats.
➔ Prevent execution of scripting files such as JavaScript and VisualBasic by changing the default ‘open-with’ settings to notepad.exe.
➔ Block or warn on uncategorized sites at the web proxy. Aside from blocking uncategorized sites, certain web proxies will display a warning page, but allow the user to continue by clicking a link in the warning page. This will stop drive-by exploits and malware from being able to download further payloads.

Rapid7 customers:

InsightIDR and Managed Detection and Response customers have existing detection coverage through Rapid7’s expansive library of detection rules. Rapid7 recommends installing the Insight Agent on all applicable hosts to ensure visibility into suspicious processes and proper detection coverage. Below is a non-exhaustive list of detections that are deployed and will alert on behavior related to this malware campaign:

  • Suspicious Process – WScript Runs JavaScript File from Temp Or Download Directory
  • Endpoint Prevention – A process attempted ‘Self Injection’ technique

MITRE ATT&CK Techniques

Tactics Technique Description
Resource Development SEO Poisoning (T1608.006) Threat Actor employed SEO poisoning, ensuring their advertisement was listed first in search results
Initial Access Drive-by Compromise (T1189) Upon successfully solving CAPTCHA, browser is directed to download a JavaScript file from another URL
Execution Command and Scripting Interpreter: JavaScript (T1059.007) User executes the downloaded JavaScript file
Defense Evasion Embedded Payloads (T1027.009) Brute Ratel payload is embedded within decrypted payload
Defense Evasion Command Obfuscation (T1027.010) Downloaded JavaScript file contains commands broken up by commented lines to hinder analysis and anti-virus scanners
Defense Evasion Encrypted/Encoded File (T1027.013) Latrodectus employs string decryption to hinder detection and analysis
Defense Evasion Deobfuscate/Decode Files or Information (T1140) DLL dropped by MSI package contains XOR routine to decrypt the Brute Ratel payload
Privilege Escalation Dynamic-link Library Injection (T1055.001) Latrodectus DLLs are injected into the Explorer.exe process
Command and Control Web Protocols (T1071.001) Brute Ratel and Latrodectus communicate with their C2 servers using HTTPS

Indicators of compromise:

Host Based Indicators (HBIs)

Indicator File Hash Description
Form_Ver-14-00-21.js F8121922AE3A189FBAE0B17C8F5E665E29E2E13B2E7144DABA4B382432B4949E JS File downloaded from URL hxxps://firebasestorage[.]googleapis.com/v0/b/namo-426715.appspot.com/o/KB9NQzOsws/Form_Ver-18-44-37.js?alt=media&token=dd7d4363-5441-4b14-af8c-1cb584f829c7
BST.msi 5b18441926e832038099acbe4a90c9e1907c9487ac14bdf4925ac170dddc24b6 MSI file downloaded from URL hxxp://85.208.108[.]63/BST.msi
neuro.msi D71BFAB9CCA5DF6A28E12BA51FE5EAF0F9151514B3FD363264513347A8C5CF3A MSI file downloaded from URL hxxp://85.208.108[.]30/nuero.msi contained within JS file
vpn.msi 4586250dbf8cbe579662d3492dd33fe0b3493323d4a060a0d391f20ecb28abf1 MSI file downloaded from URL hxxp://193.32.177[.]192/vpn.msi contained within JS file
aclui.dll 8484560C1526EE2E313A2B57F52EA5B31EDD05A0C9664BD7F60DA020871BFE6F DLL contained within MSI file BST.msi and vpn.msi
capisp.dll 9B7BDB4CB71E84C5CFF0923928BF7777A41CB5E0691810AE948304C151C0C1C5 DLL contained within MSI file neuro.msi
BruteRatel payload AD4A8983EDFB0DBA81E3D0BAE1AB549B500FD8A07DAF601E616B7E721D0674C6 BruteRatel decrypted payload contained within capisp.dll

Network Based Indicators (NBIs)

Indicator Description
appointopia[.]com Domain used for SEO poisoning that redirects to URL hxxps://grupotefex[.]com/forms-pubs/about-form-w-2/
hxxps://grupotefex[.]com/forms-pubs/about-form-w-2/ URL containing fake IRS website, luring users into trying to download W2 form
85.208.108[.]63 Domain hosting BST.msi
193.32.177[.]192 Domain hosting vpn.msi
85.208.108[.]30 Domain hosting neuro.msi
kurvabbr[.]pw BruteRatel C2 – Payload contained within aclui.dll
barsen[.]monster BruteRatel C2 – Payload contained within aclui.dll
barsman[.]biz BruteRatel C2 – Payload contained within capisp.dll
bibidj[.]biz BruteRatel C2 – Payload contained within capisp.dll
garunt[.]biz BruteRatel C2 – Payload contained within capisp.dll
hxxps://meakdgahup[.]com/live/ Latrodectus C2
hxxps://riscoarchez[.]com/live/ Latrodectus C2
hxxps://jucemaster[.]space/live/ Latrodectus C2
hxxps://finjuiceer[.]com/live/ Latrodectus C2
hxxps://trymeakafr[.]com/live/ Latrodectus C2


Article URL
Zscaler ThreatLabz Post https://x.com/Threatlabz/status/1804918852528357791
Latrodectus Affiliate Resumes Operations Using Brute Ratel C4 Post Operation Endgame https://blog.reveng.ai/latrodectus-distribution-via-brc4/

The Justice Department Took Down the 911 S5 Botnet

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/06/the-justice-department-took-down-the-911-s5-botnet.html

The US Justice Department has dismantled an enormous botnet:

According to an indictment unsealed on May 24, from 2014 through July 2022, Wang and others are alleged to have created and disseminated malware to compromise and amass a network of millions of residential Windows computers worldwide. These devices were associated with more than 19 million unique IP addresses, including 613,841 IP addresses located in the United States. Wang then generated millions of dollars by offering cybercriminals access to these infected IP addresses for a fee.


This operation was a coordinated multiagency effort led by law enforcement in the United States, Singapore, Thailand, and Germany. Agents and officers searched residences, seized assets valued at approximately $30 million, and identified additional forfeitable property valued at approximately $30 million. The operation also seized 23 domains and over 70 servers constituting the backbone of Wang’s prior residential proxy service and the recent incarnation of the service. By seizing multiple domains tied to the historical 911 S5, as well as several new domains and services directly linked to an effort to reconstitute the service, the government has successfully terminated Wang’s efforts to further victimize individuals through his newly formed service Clourouter.io and closed the existing malicious backdoors.

The creator and operator of the botnet, YunHe Wang, was arrested in Singapore.

Three news articles.

Disrupting FlyingYeti’s campaign targeting Ukraine

Post Syndicated from Cloudforce One original https://blog.cloudflare.com/disrupting-flyingyeti-campaign-targeting-ukraine

Cloudforce One is publishing the results of our investigation and real-time effort to detect, deny, degrade, disrupt, and delay threat activity by the Russia-aligned threat actor FlyingYeti during their latest phishing campaign targeting Ukraine. At the onset of Russia’s invasion of Ukraine on February 24, 2022, Ukraine introduced a moratorium on evictions and termination of utility services for unpaid debt. The moratorium ended in January 2024, resulting in significant debt liability and increased financial stress for Ukrainian citizens. The FlyingYeti campaign capitalized on anxiety over the potential loss of access to housing and utilities by enticing targets to open malicious files via debt-themed lures. If opened, the files would result in infection with the PowerShell malware known as COOKBOX, allowing FlyingYeti to support follow-on objectives, such as installation of additional payloads and control over the victim’s system.

Since April 26, 2024, Cloudforce One has taken measures to prevent FlyingYeti from launching their phishing campaign – a campaign involving the use of Cloudflare Workers and GitHub, as well as exploitation of the WinRAR vulnerability CVE-2023-38831. Our countermeasures included internal actions, such as detections and code takedowns, as well as external collaboration with third parties to remove the actor’s cloud-hosted malware. Our effectiveness against this actor prolonged their operational timeline from days to weeks. For example, in a single instance, FlyingYeti spent almost eight hours debugging their code as a result of our mitigations. By employing proactive defense measures, we successfully stopped this determined threat actor from achieving their objectives.

Executive Summary

  • On April 18, 2024, Cloudforce One detected the Russia-aligned threat actor FlyingYeti preparing to launch a phishing espionage campaign targeting individuals in Ukraine.
  • We discovered the actor used similar tactics, techniques, and procedures (TTPs) as those detailed in Ukranian CERT’s article on UAC-0149, a threat group that has primarily targeted Ukrainian defense entities with COOKBOX malware since at least the fall of 2023.
  • From mid-April to mid-May, we observed FlyingYeti conduct reconnaissance activity, create lure content for use in their phishing campaign, and develop various iterations of their malware. We assessed that the threat actor intended to launch their campaign in early May, likely following Orthodox Easter.
  • After several weeks of monitoring actor reconnaissance and weaponization activity (Cyber Kill Chain Stages 1 and 2), we successfully disrupted FlyingYeti’s operation moments after the final COOKBOX payload was built.
  • The payload included an exploit for the WinRAR vulnerability CVE-2023-38831, which FlyingYeti will likely continue to use in their phishing campaigns to infect targets with malware.
  • We offer steps users can take to defend themselves against FlyingYeti phishing operations, and also provide recommendations, detections, and indicators of compromise.

Who is FlyingYeti?

FlyingYeti is the cryptonym given by Cloudforce One to the threat group behind this phishing campaign, which overlaps with UAC-0149 activity tracked by CERT-UA in February and April 2024. The threat actor uses dynamic DNS (DDNS) for their infrastructure and leverages cloud-based platforms for hosting malicious content and for malware command and control (C2). Our investigation of FlyingYeti TTPs suggests this is likely a Russia-aligned threat group. The actor appears to primarily focus on targeting Ukrainian military entities. Additionally, we observed Russian-language comments in FlyingYeti’s code, and the actor’s operational hours falling within the UTC+3 time zone.

Campaign background

In the days leading up to the start of the campaign, Cloudforce One observed FlyingYeti conducting reconnaissance on payment processes for Ukrainian communal housing and utility services:

  • April 22, 2024 – research into changes made in 2016 that introduced the use of QR codes in payment notices
  • April 22, 2024 – research on current developments concerning housing and utility debt in Ukraine
  • April 25, 2024 – research on the legal basis for restructuring housing debt in Ukraine as well as debt involving utilities, such as gas and electricity

Cloudforce One judges that the observed reconnaissance is likely due to the Ukrainian government’s payment moratorium introduced at the start of the full-fledged invasion in February 2022. Under this moratorium, outstanding debt would not lead to evictions or termination of provision of utility services. However, on January 9, 2024, the government lifted this ban, resulting in increased pressure on Ukrainian citizens with outstanding debt. FlyingYeti sought to capitalize on that pressure, leveraging debt restructuring and payment-related lures in an attempt to increase their chances of successfully targeting Ukrainian individuals.

Analysis of the Komunalka-themed phishing site

The disrupted phishing campaign would have directed FlyingYeti targets to an actor-controlled GitHub page at hxxps[:]//komunalka[.]github[.]io, which is a spoofed version of the Kyiv Komunalka communal housing site https://www.komunalka.ua. Komunalka functions as a payment processor for residents in the Kyiv region and allows for payment of utilities, such as gas, electricity, telephone, and Internet. Additionally, users can pay other fees and fines, and even donate to Ukraine’s defense forces.

Based on past FlyingYeti operations, targets may be directed to the actor’s Github page via a link in a phishing email or an encrypted Signal message. If a target accesses the spoofed Komunalka platform at hxxps[:]//komunalka[.]github[.]io, the page displays a large green button with a prompt to download the document “Рахунок.docx” (“Invoice.docx”), as shown in Figure 1. This button masquerades as a link to an overdue payment invoice but actually results in the download of the malicious archive “Заборгованість по ЖКП.rar” (“Debt for housing and utility services.rar”).

Figure 1: Prompt to download malicious archive “Заборгованість по ЖКП.rar”

A series of steps must take place for the download to successfully occur:

  • The target clicks the green button on the actor’s GitHub page hxxps[:]//komunalka.github[.]io
  • The target’s device sends an HTTP POST request to the Cloudflare Worker worker-polished-union-f396[.]vqu89698[.]workers[.]dev with the HTTP request body set to “user=Iahhdr”
  • The Cloudflare Worker processes the request and evaluates the HTTP request body
  • If the request conditions are met, the Worker fetches the RAR file from hxxps[:]//raw[.]githubusercontent[.]com/kudoc8989/project/main/Заборгованість по ЖКП.rar, which is then downloaded on the target’s device

Cloudforce One identified the infrastructure responsible for facilitating the download of the malicious RAR file and remediated the actor-associated Worker, preventing FlyingYeti from delivering its malicious tooling. In an effort to circumvent Cloudforce One’s mitigation measures, FlyingYeti later changed their malware delivery method. Instead of the Workers domain fetching the malicious RAR file, it was loaded directly from GitHub.

Analysis of the malicious RAR file

During remediation, Cloudforce One recovered the RAR file “Заборгованість по ЖКП.rar” and performed analysis of the malicious payload. The downloaded RAR archive contains multiple files, including a file with a name that contains the unicode character “U+201F”. This character appears as whitespace on Windows devices and can be used to “hide” file extensions by adding excessive whitespace between the filename and the file extension. As highlighted in blue in Figure 2, this cleverly named file within the RAR archive appears to be a PDF document but is actually a malicious CMD file (“Рахунок на оплату.pdf[unicode character U+201F].cmd”).

Figure 2: Files contained in the malicious RAR archive “Заборгованість по ЖКП.rar” (“Housing Debt.rar”)

FlyingYeti included a benign PDF in the archive with the same name as the CMD file but without the unicode character, “Рахунок на оплату.pdf” (“Invoice for payment.pdf”). Additionally, the directory name for the archive once decompressed also contained the name “Рахунок на оплату.pdf”. This overlap in names of the benign PDF and the directory allows the actor to exploit the WinRAR vulnerability CVE-2023-38831. More specifically, when an archive includes a benign file with the same name as the directory, the entire contents of the directory are opened by the WinRAR application, resulting in the execution of the malicious CMD. In other words, when the target believes they are opening the benign PDF “Рахунок на оплату.pdf”, the malicious CMD file is executed.

The CMD file contains the FlyingYeti PowerShell malware known as COOKBOX. The malware is designed to persist on a host, serving as a foothold in the infected device. Once installed, this variant of COOKBOX will make requests to the DDNS domain postdock[.]serveftp[.]com for C2, awaiting PowerShell cmdlets that the malware will subsequently run.

Alongside COOKBOX, several decoy documents are opened, which contain hidden tracking links using the Canary Tokens service. The first document, shown in Figure 3 below, poses as an agreement under which debt for housing and utility services will be restructured.

Figure 3: Decoy document Реструктуризація боргу за житлово комунальні послуги.docx

The second document (Figure 4) is a user agreement outlining the terms and conditions for the usage of the payment platform komunalka[.]ua.

Figure 4: Decoy document Угода користувача.docx (User Agreement.docx)

The use of relevant decoy documents as part of the phishing and delivery activity are likely an effort by FlyingYeti operators to increase the appearance of legitimacy of their activities.

The phishing theme we identified in this campaign is likely one of many themes leveraged by this actor in a larger operation to target Ukrainian entities, in particular their defense forces. In fact, the threat activity we detailed in this blog uses many of the same techniques outlined in a recent FlyingYeti campaign disclosed by CERT-UA in mid-April 2024, where the actor leveraged United Nations-themed lures involving Peace Support Operations to target Ukraine’s military. Due to Cloudforce One’s defensive actions covered in the next section, this latest FlyingYeti campaign was prevented as of the time of publication.

Mitigating FlyingYeti activity

Cloudforce One mitigated FlyingYeti’s campaign through a series of actions. Each action was taken to increase the actor’s cost of continuing their operations. When assessing which action to take and why, we carefully weighed the pros and cons in order to provide an effective active defense strategy against this actor. Our general goal was to increase the amount of time the threat actor spent trying to develop and weaponize their campaign.

We were able to successfully extend the timeline of the threat actor’s operations from hours to weeks. At each interdiction point, we assessed the impact of our mitigation to ensure the actor would spend more time attempting to launch their campaign. Our mitigation measures disrupted the actor’s activity, in one instance resulting in eight additional hours spent on debugging code.

Due to our proactive defense efforts, FlyingYeti operators adapted their tactics multiple times in their attempts to launch the campaign. The actor originally intended to have the Cloudflare Worker fetch the malicious RAR file from GitHub. After Cloudforce One interdiction of the Worker, the actor attempted to create additional Workers via a new account. In response, we disabled all Workers, leading the actor to load the RAR file directly from GitHub. Cloudforce One notified GitHub, resulting in the takedown of the RAR file, the GitHub project, and suspension of the account used to host the RAR file. In return, FlyingYeti began testing the option to host the RAR file on the file sharing sites pixeldrain and Filemail, where we observed the actor alternating the link on the Komunalka phishing site between the following:

  • hxxps://pixeldrain[.]com/api/file/ZAJxwFFX?download=one
  • hxxps://1014.filemail[.]com/api/file/get?filekey=e_8S1HEnM5Rzhy_jpN6nL-GF4UAP533VrXzgXjxH1GzbVQZvmpFzrFA&pk_vid=a3d82455433c8ad11715865826cf18f6

We notified GitHub of the actor’s evolving tactics, and in response GitHub removed the Komunalka phishing site. After analyzing the files hosted on pixeldrain and Filemail, we determined the actor uploaded dummy payloads, likely to monitor access to their phishing infrastructure (FileMail logs IP addresses, and both file hosting sites provide view and download counts). At the time of publication, we did not observe FlyingYeti upload the malicious RAR file to either file hosting site, nor did we identify the use of alternative phishing or malware delivery methods.

A timeline of FlyingYeti’s activity and our corresponding mitigations can be found below.

Event timeline

Date Event Description
2024-04-18 12:18 Threat Actor (TA) creates a Worker to handle requests from a phishing site
2024-04-18 14:16 TA creates phishing site komunalka[.]github[.]io on GitHub
2024-04-25 12:25 TA creates a GitHub repo to host a RAR file
2024-04-26 07:46 TA updates the first Worker to handle requests from users visiting komunalka[.]github[.]io
2024-04-26 08:24 TA uploads a benign test RAR to the GitHub repo
2024-04-26 13:38 Cloudforce One identifies a Worker receiving requests from users visiting komunalka[.]github[.]io, observes its use as a phishing page
2024-04-26 13:46 Cloudforce One identifies that the Worker fetches a RAR file from GitHub (the malicious RAR payload is not yet hosted on the site)
2024-04-26 19:22 Cloudforce One creates a detection to identify the Worker that fetches the RAR
2024-04-26 21:13 Cloudforce One deploys real-time monitoring of the RAR file on GitHub
2024-05-02 06:35 TA deploys a weaponized RAR (CVE-2023-38831) to GitHub with their COOKBOX malware packaged in the archive
2024-05-06 10:03 TA attempts to update the Worker with link to weaponized RAR, the Worker is immediately blocked
2024-05-06 10:38 TA creates a new Worker, the Worker is immediately blocked
2024-05-06 11:04 TA creates a new account (#2) on Cloudflare
2024-05-06 11:06 TA creates a new Worker on account #2 (blocked)
2024-05-06 11:50 TA creates a new Worker on account #2 (blocked)
2024-05-06 12:22 TA creates a new modified Worker on account #2
2024-05-06 16:05 Cloudforce One disables the running Worker on account #2
2024-05-07 22:16 TA notices the Worker is blocked, ceases all operations
2024-05-07 22:18 TA deletes original Worker first created to fetch the RAR file from the GitHub phishing page
2024-05-09 19:28 Cloudforce One adds phishing page komunalka[.]github[.]io to real-time monitoring
2024-05-13 07:36 TA updates the github.io phishing site to point directly to the GitHub RAR link
2024-05-13 17:47 Cloudforce One adds COOKBOX C2 postdock[.]serveftp[.]com to real-time monitoring for DNS resolution
2024-05-14 00:04 Cloudforce One notifies GitHub to take down the RAR file
2024-05-15 09:00 GitHub user, project, and link for RAR are no longer accessible
2024-05-21 08:23 TA updates Komunalka phishing site on github.io to link to pixeldrain URL for dummy payload (pixeldrain only tracks view and download counts)
2024-05-21 08:25 TA updates Komunalka phishing site to link to FileMail URL for dummy payload (FileMail tracks not only view and download counts, but also IP addresses)
2024-05-21 12:21 Cloudforce One downloads PixelDrain document to evaluate payload
2024-05-21 12:47 Cloudforce One downloads FileMail document to evaluate payload
2024-05-29 23:59 GitHub takes down Komunalka phishing site
2024-05-30 13:00 Cloudforce One publishes the results of this investigation

Coordinating our FlyingYeti response

Cloudforce One leveraged industry relationships to provide advanced warning and to mitigate the actor’s activity. To further protect the intended targets from this phishing threat, Cloudforce One notified and collaborated closely with GitHub’s Threat Intelligence and Trust and Safety Teams. We also notified CERT-UA and Cloudflare industry partners such as CrowdStrike, Mandiant/Google Threat Intelligence, and Microsoft Threat Intelligence.

Hunting FlyingYeti operations

There are several ways to hunt FlyingYeti in your environment. These include using PowerShell to hunt for WinRAR files, deploying Microsoft Sentinel analytics rules, and running Splunk scripts as detailed below. Note that these detections may identify activity related to this threat, but may also trigger unrelated threat activity.

PowerShell hunting

Consider running a PowerShell script such as this one in your environment to identify exploitation of CVE-2023-38831. This script will interrogate WinRAR files for evidence of the exploit.

Description:winrar exploit detection 
open suspios (.tar / .zip / .rar) and run this script to check it 

function winrar-exploit-detect(){
$targetExtensions = @(".cmd" , ".ps1" , ".bat")
$tempDir = [System.Environment]::GetEnvironmentVariable("TEMP")
$dirsToCheck = Get-ChildItem -Path $tempDir -Directory -Filter "Rar*"
foreach ($dir in $dirsToCheck) {
    $files = Get-ChildItem -Path $dir.FullName -File
    foreach ($file in $files) {
        $fileName = $file.Name
        $fileExtension = [System.IO.Path]::GetExtension($fileName)
        if ($targetExtensions -contains $fileExtension) {
            $fileWithoutExtension = [System.IO.Path]::GetFileNameWithoutExtension($fileName); $filename.TrimEnd() -replace '\.$'
            $cmdFileName = "$fileWithoutExtension"
            $secondFile = Join-Path -Path $dir.FullName -ChildPath $cmdFileName
            if (Test-Path $secondFile -PathType Leaf) {
                Write-Host "[!] Suspicious pair detected "
                Write-Host "[*]  Original File:$($secondFile)" -ForegroundColor Green 
                Write-Host "[*] Suspicious File:$($file.FullName)" -ForegroundColor Red

                # Read and display the content of the command file
                $cmdFileContent = Get-Content -Path $($file.FullName)
                Write-Host "[+] Command File Content:$cmdFileContent"

Microsoft Sentinel

In Microsoft Sentinel, consider deploying the rule provided below, which identifies WinRAR execution via cmd.exe. Results generated by this rule may be indicative of attack activity on the endpoint and should be analyzed.

| where InitiatingProcessParentFileName has @"winrar.exe"
| where InitiatingProcessFileName has @"cmd.exe"
| project Timestamp, DeviceName, FileName, FolderPath, ProcessCommandLine, AccountName
| sort by Timestamp desc


Consider using this script in your Splunk environment to look for WinRAR CVE-2023-38831 execution on your Microsoft endpoints. Results generated by this script may be indicative of attack activity on the endpoint and should be analyzed.

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=winrar.exe `windows_shells` OR Processes.process_name IN ("certutil.exe","mshta.exe","bitsadmin.exe") by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `winrar_spawning_shell_application_filter`

Cloudflare product detections

Cloudflare Email Security

Cloudflare Email Security (CES) customers can identify FlyingYeti threat activity with the following detections.

  • CVE-2023-38831


Cloudflare recommends taking the following steps to mitigate this type of activity:

  • Implement Zero Trust architecture foundations:    
  • Deploy Cloud Email Security to ensure that email services are protected against phishing, BEC and other threats
  • Leverage browser isolation to separate messaging applications like LinkedIn, email, and Signal from your main network
  • Scan, monitor and/or enforce controls on specific or sensitive data moving through your network environment with data loss prevention policies
  • Ensure your systems have the latest WinRAR and Microsoft security updates installed
  • Consider preventing WinRAR files from entering your environment, both at your Cloud Email Security solution and your Internet Traffic Gateway
  • Run an Endpoint Detection and Response (EDR) tool such as CrowdStrike or Microsoft Defender for Endpoint to get visibility into binary execution on hosts
  • Search your environment for the FlyingYeti indicators of compromise (IOCs) shown below to identify potential actor activity within your network.

If you’re looking to uncover additional Threat Intelligence insights for your organization or need bespoke Threat Intelligence information for an incident, consider engaging with Cloudforce One by contacting your Customer Success manager or filling out this form.

Indicators of Compromise

Filename SHA256 Hash Description
Заборгованість по ЖКП.rar a0a294f85c8a19be048ffcc05ede6fd5a7ac5e2f0032a3ca0050dc1ae960c314 RAR archive
Рахунок на оплату.pdf
0cca8f795c7a81d33d36d5204fcd9bc73bdc2af7de315c1449cbc3551ef4fb59 COOKBOX Sample (contained in RAR archive)
Реструктуризація боргу за житлово комунальні послуги.docx 915721b94e3dffa6cef3664532b586be6cf989fec923b26c62fdaf201ee81d2c Benign Word Document with Tracking Link (contained in RAR archive)
Угода користувача.docx 79a9740f5e5ea4aa2157d9d96df34ee49a32e2d386fe55fedfd1aa33e151c06d Benign Word Document with Tracking Link (contained in RAR archive)
Рахунок на оплату.pdf 19e25456c2996ded3e29577b609de54a2bef90dad8f868cdad795c18df05a79b Random Binary Data (contained in RAR archive)
Заборгованість по ЖКП станом на 26.04.24.docx e0d65e2d36afd3db1b603f10e0488cee3f58ade24d8abc6bee240314d8696708 Random Binary Data (contained in RAR archive)
Domain / URL Description
komunalka[.]github[.]io Phishing page
hxxps[:]//github[.]com/komunalka/komunalka[.]github[.]io Phishing page
hxxps[:]//worker-polished-union-f396[.]vqu89698[.]workers[.]dev Worker that fetches malicious RAR file
hxxps[:]//raw[.]githubusercontent[.]com/kudoc8989/project/main/Заборгованість по ЖКП.rar Delivery of malicious RAR file
hxxps[:]//1014[.]filemail[.]com/api/file/get?filekey=e_8S1HEnM5Rzhy_jpN6nL-GF4UAP533VrXzgXjxH1GzbVQZvmpFzrFA&pk_vid=a3d82455433c8ad11715865826cf18f6 Dummy payload
hxxps[:]//pixeldrain[.]com/api/file/ZAJxwFFX?download= Dummy payload
hxxp[:]//canarytokens[.]com/stuff/tags/ni1cknk2yq3xfcw2al3efs37m/payments.js Tracking link
hxxp[:]//canarytokens[.]com/stuff/terms/images/k22r2dnjrvjsme8680ojf5ccs/index.html Tracking link
postdock[.]serveftp[.]com COOKBOX C2

Ongoing Malvertising Campaign leads to Ransomware

Post Syndicated from Tyler McGraw original https://blog.rapid7.com/2024/05/13/ongoing-malvertising-campaign-leads-to-ransomware/

Executive Summary

Ongoing Malvertising Campaign leads to Ransomware

Rapid7 has observed an ongoing campaign to distribute trojanized installers for WinSCP and PuTTY via malicious ads on commonly used search engines, where clicking on the ad leads to typo squatted domains. In at least one observed case, the infection has led to the attempted deployment of ransomware. The analysis conducted by Rapid7 features updates to past research, including a variety of new indicators of compromise, a YARA rule to help identify malicious DLLs, and some observed changes to the malware’s functionality.  Rapid7 has observed the campaign disproportionately affects members of IT teams, who are most likely to download the trojanized files while looking for legitimate versions. Successful execution of the malware then provides the threat actor with an elevated foothold and impedes analysis by blurring the intentions of subsequent administrative actions.

Ongoing Malvertising Campaign leads to Ransomware
Figure 1. Simplified overview of the attack flow.


Beginning in early March 2024, Rapid7 observed the distribution of trojanized installers for the open source utilities WinSCP and PuTTy. WinSCP is a file transfer client, PuTTY a secure shell (SSH) client. The infection chain typically begins after a user searches for a phrase such as download winscp or download putty, on a search engine like Microsoft’s Bing. The search results include an ad for the software the user clicks on, which ultimately redirects them to either a clone of the legitimate website, in the case of WinSCP, or a simple download page in the case of PuTTY. In both cases, a link to download a zip archive containing the trojan from a secondary domain was embedded on the web page.

Ongoing Malvertising Campaign leads to Ransomware
Figure 2. Appearance of the cloned WinSCP website.

The infection begins after the user has downloaded and extracted the contents of the zip archive and executed setup.exe, which is a renamed copy of pythonw.exe, the legitimate Python hidden console window executable.

Ongoing Malvertising Campaign leads to Ransomware
Figure 3. Files contained within an archive targeting WinSCP.

Upon execution, setup.exe loads the malicious DLL python311.dll. As seen in Figure 2, the copy of the legitimate python311 DLL which setup.exe is intended to load has actually been renamed to python311x.dll. This technique is known as DLL side-loading, where a malicious DLL can be loaded into a legitimate, signed, executable by mimicking partial functionality and the name of the original library. The process of side-loading the DLL is also facilitated by hijacking the DLL search order, where attempts are made to load DLLs contained within the same directory first, before checking other directories on the system where a legitimate copy might be present. Rapid7 has also observed the Python 3.11 library being targeted in prior malware campaigns, such as the novel IDAT loader, discovered by Rapid7 during August of 2023.

The primary payload contained within python311.dll is a compressed archive encrypted and included within the DLL’s resource section. During execution, this archive is unpacked to execute two child processes.

Ongoing Malvertising Campaign leads to Ransomware
Figure 4. The process tree spawned by the malware.

First, the malware executes the unpacked copy of the legitimate WinSCP installer, seen in Figure 3 as WinSCP-6.1.1-Setup.exe. Then, the malicious Python script systemd.py is executed via pythonw.exe after being unpacked into the staging directory %LOCALAPPDATA%\Oracle\ along with numerous Python dependencies. Following the successful execution of both processes, setup.exe then terminates.

The script systemd.py, executed via pythonw.exe, decrypts and executes a second Python script then performs decryption and reflective DLL injection of a Sliver beacon. Reflective DLL injection is the process of loading a library into a process directly from memory instead of from disk. In several cases, Rapid7 observed the threat actor take quick action upon successful contact with the Sliver beacon, downloading additional payloads, including Cobalt Strike beacons. The access is then used to establish persistence via scheduled tasks and newly created services after pivoting via SMB. In a recent incident, Rapid7 observed the threat actor attempt to exfiltrate data using the backup utility Restic, and then deploy ransomware, an attempt which was ultimately blocked during execution.

The related techniques, tactics, and procedures (TTP) observed by Rapid7 are reminiscent of past BlackCat/ALPHV campaigns as reported by Trend Micro last year. This campaign, referred to as Nitrogen by Malwarebytes, and eSentire, has previously been reported to use similar methods.

Technical Analysis

To take a more in depth look at the malware delivery and functionality, we analyzed a malware sample recently observed being delivered to users looking for a PuTTY installer.

Initial Access

The source of the infection was a malicious ad served to the user after their search for download putty. When the user clicked on the ad, which are typically pushed to the top of the search results for visibility, they were redirected to a typo-squatted domain at the URL hxxps://puttty[.]org/osn.php. The landing page includes a download button for PuTTY, as well as two legitimate links to download a Bitvise SSH server/client. However, when the download link is clicked by the user it calls the embedded function loadlink(), which redirects the user to hxxps://puttty[.]org/dwnl.php, which then finally redirects the user to the most recent host of the malicious zip archive to serve the download. At the time of writing, puttty[.]org and the relevant URLs were still active, serving the zip archive putty-0.80-installer.zip from the likely compromised WordPress domain areauni[.]com.

Ongoing Malvertising Campaign leads to Ransomware
Figure 5. Landing page for the malicious ad.

Rapid7 observed the base domain, puttty[.]org was also serving a cloned version of a PuTTY help article available at BlueHost, where the download link provided is actually for the official distributor of the software. This relatively benign page is most likely conditionally served as a way to reduce suspicion as noted by Malwarebytes.

In comparison, the typo-squatted WinSCP domains conditionally redirected visits to Rick Astley’s Never Gonna Give You Up. Classic.


Upon extracting the zip archive putty-0.80-installer.zip, the user is once again presented with setup.exe, a renamed copy of pythonw.exe, to entice the user to initiate the infection by launching the executable.

Ongoing Malvertising Campaign leads to Ransomware
Figure 7. The extracted contents of putty-0.80-installer.zip.

Once executed, setup.exe will side-load the malicious DLL python311.dll. The DLL python311.dll then loads a renamed copy of the legitimate DLL, python3.dll, from the same directory after dynamically resolving the necessary functions from kernel32.dll by string match. Future requests for exported functions made by setup.exe can then be forwarded to python3.dll by python311.dll. This technique is commonly used when side-loading malware, so legitimate requests are proxied, which avoids unexpected behavior and improves stability of the payload delivery.

Ongoing Malvertising Campaign leads to Ransomware
Figure 8. Dynamic resolution of GetProcAddress.

Following the successful sideloading procedure, the malware then performs pre-unpacking setup by dynamically resolving additional functions from ntdll.dll. The malware still uses functionality similar to the publicly available AntiHook and KrakenMask libraries to facilitate setup and execution, as previously noted by eSentire, which provides additional evasion capabilities. AntiHook contains functionality to enumerate the loaded modules of a process, searching each one for hooks, and remaps a clean, unhooked version of the module’s text section, if hooks are found. KrakenMask contains functionality to spoof the return address of function calls, to evade stack traces, and functionality to encrypt the processes virtual memory at rest to evade memory scanners.

Ongoing Malvertising Campaign leads to Ransomware
Figure 9. ASM stub containing the return address spoofing logic, as seen in KrakenMask.
Ongoing Malvertising Campaign leads to Ransomware
Figure 10. Snippet of the function that performs byte comparisons to check for hooks, as seen in AntiHook.

The library ntdll.dll contains functions which make up the Windows Native API (NTAPI), which is generally the closest a process executed in user mode can get to utilizing functionality from the operating system’s kernel. By resolving NTAPI functions for use, malware can bypass detection applied to more commonly used user mode functions (WINAPI) and access lower level functionality that is otherwise unavailable. Several of the NTAPI function pointers resolved by the malware can be used for evasion techniques such as Event Tracing for Windows (ETW) tampering and bypass of the Anti-Malware Scan Interface (AMSI) as has been observed in prior Nitrogen campaign samples. Some of the functions are dynamically resolved from ntdll.dll are found using concatenation of stack strings to form the full name of the target API just before resolution is attempted, likely to help evade detection.

Resolved ntdll.dll functions

Table 1. Functions the malware dynamically resolves from ntdll.dll.

Other observed function strings
WldpQueryDynamicCodeTrust (wldp.dll)
AmsiScanBuffer (amsi.dll)

Table 2. Other evasion related WINAPI function strings observed in the malware

With setup complete, an encrypted resource stored within the resource section of python311.dll is retrieved using common resource WINAPI calls, including FindResourceA, LoadResource, SizeOfResource, and FreeResource.

Ongoing Malvertising Campaign leads to Ransomware
Figure 11. The encrypted resource is loaded into memory and decrypted using AES-256.

The resource is then decrypted in memory using an AES-256 hex key and initialization vector (IV) that are stored in the data section in plain text. The resulting file is a zip archive which contains three compressed files, including a legitimate MSI installation package for PuTTY and another compressed archive named installer_data.zip.

Ongoing Malvertising Campaign leads to Ransomware
Figure 12. Decrypted and decompressed contents of the resource.

To execute the PuTTY installer, the malware first creates a copy of the MSI file in the hard-coded directory C:\Users\Public\Downloads\ via a call to fopen and then decompresses and writes the retrieved MSI package content with multiple successive calls to fwrite and other CRT library file io functions, followed by fclose. The full output path is assembled by concatenating the target directory with the desired file name, which is retrieved from original_installer.txt. The contents of original_installer.txt are identical to the name of the MSI package observed in the resource, for this sample: putty-64bit-0.78-installer.msi.

Ongoing Malvertising Campaign leads to Ransomware
Figure 13. The malware creates the PuTTY MSI package within the public downloads directory.

The MSI package is then executed by a call to CreateProcessW with the command line msiexec.exe ALLUSERS=1 /i C:\Users\Public\Downloads\putty-64bit-0.78-installer.msi. So, before the execution of the next malware payload the user is provided with the software they were originally looking for. This functionality is commonly seen with trojans to avoid suspicion by the end user, as the user only sees the legitimate installation window pop up after initial execution. However, the version numbers between the executed MSI package, putty-64bit-0.78-installer.msi, and the initially downloaded zip archive, putty-64bit-0.80-installer.zip, don’t match — a potential indicator.

Ongoing Malvertising Campaign leads to Ransomware
Figure 14. The user only sees the installation window after executing setup.exe.

The same procedure is then repeated to copy the decompressed contents of the folder Oracle contained within the zip archive installer_data.zip to the staging directory created at %LOCALAPPDATA%\Oracle\. After the unpacking process is complete, another call by the malware to CreateProcessW executes the next payload with the command line %LOCALAPPDATA%\Oracle\pythonw.exe %LOCALAPPDATA%\Oracle\systemd.py. With its purpose completed, the loader then clears memory and passes back control to setup.exe, which promptly terminates, leaving the pythonw.exe process running in the background.

Ongoing Malvertising Campaign leads to Ransomware
Figure 15. Core functionality of systemd.py.

The Python script systemd.py contains multiple junk classes, which in turn contain numerous junk function definitions to pad out the core script. Ultimately, the script decrypts the file %LOCALAPPDATA%\Oracle\data.aes, which is a Sliver beacon DLL (original name: BALANCED_NAPKIN.dll), performs local injection of the Sliver DLL, and then calls the export StartW. The contents of main and other included functionality within the script appears to have been mostly copied from the publicly available Github repo for PythonMemoryModule.

Ongoing Malvertising Campaign leads to Ransomware
Figure 16. Strings within the DLL: The beacon was clearly generated by the Sliver framework.

Rapid7 has replicated the unpacking process of the beacon DLL in a python extraction script that is now publicly available along with a yara rule to detect the malicious DLL.


Rapid7 recommends verifying the download source of freely available software. Check that the hash of the downloaded file(s) match those provided by the official distributor and that they contain a valid and relevant signature. The DLLs that are side-loaded by malware are often unsigned, and are often present in the same location as the legitimately signed and renamed original, to which requests are forwarded. Bookmark the official distribution domains for the download of future updates.

DNS requests for permutations of known domains can also be proactively blocked or the requests can be redirected to a DNS sinkhole. For example, by using the publicly available tool DNSTwist we can identify several additional suspicious domains that match the observed ASNs and country codes observed for many of the C2 IPv4 addresses observed to be contacted by the malware as well as known malware hosts/facilitators.

Domain IPv4 ASN
wnscp[.]net 91.92.253[.]80 AS394711:LIMENET
puttyy[.]org 82.221.136[.]24 AS50613:Advania Island ehf
puutty[.]org 82.221.129[.]39 AS50613:Advania Island ehf
putyy[.]org 82.221.136[.]1 AS50613:Advania Island ehf

Table 3. More suspicious domains found via DNSTwist.

Rapid7 observed impacted users are disproportionately members of information technology (IT) teams who are more likely to download installers for utilities like PuTTY and WinSCP for updates or setup. When the account of an IT member is compromised, the threat actor gains a foothold with elevated privileges which impedes analysis by blending in their actions with that of the administrator(s), stressing the importance of verifying the source of files before download, and their contents before execution.

MITRE ATT&CK Techniques

Tactic Technique Procedure
Resource Development T1583.008: Acquire Infrastructure: Malvertising The threat actor uses ads to promote malware delivery via popular search engines.
Initial Access T1189: Drive-by Compromise The user clicks on a malicious ad populated from a typical search engine query for a software utility and is ultimately redirected to a page hosting malware.
Execution T1106: Native API The malware dynamically resolves and executes functions from ntdll.dll at runtime.
Execution T1204.002: User Execution: Malicious File The user downloads and executes setup.exe (renamed pythonw.exe), which side-loads and executes the malicious DLL python311.dll.
Execution T1059.006: Command and Scripting Interpreter: Python The malware executes a python script to load and execute a Sliver beacon.
Persistence T1543.003: Create or Modify System Process: Windows Service The threat actor creates a service to execute a C2 beacon. The threat actor loads a vulnerable driver to facilitate disabling antivirus software and other defenses present.
Persistence T1053.005: Scheduled Task/Job: Scheduled Task The threat actor creates a scheduled task to execute a C2 beacon.
Defense Evasion T1140: Deobfuscate/Decode Files or Information The malware uses various string manipulation and obfuscation techniques.
Defense Evasion T1222.001: File and Directory Permissions Modification: Windows File and Directory Permissions Modification The malware calls chmod to change file permissions prior to execution.
Defense Evasion T1574.001: Hijack Execution Flow: DLL Search Order Hijacking The malware contained in python311.dll is loaded by a renamed copy of pythonw.exe from the same directory.
Defense Evasion T1574.002: Hijack Execution Flow: DLL Side-Loading The malware contained in python311.dll is loaded by a renamed copy of pythonw.exe and proxies requests to a renamed copy of the legitimate DLL.
Defense Evasion T1027.002: Obfuscated Files or Information: Software Packing The final payload executed by the malware is unpacked through several layers of compression, encryption, and file formats.
Defense Evasion T1027.013: Obfuscated Files or Information: Encrypted/Encoded File The malware also stores other file dependencies with several layers of obfuscation
Defense Evasion T1055.001: Process Injection: Dynamic-link Library Injection The malware loads a Sliver beacon DLL via python script.
Lateral Movement T1570: Lateral Tool Transfer The threat actor uses SMB via Cobalt Strike to pivot post compromise
Exfiltration T1567.002: Exfiltration Over Web Service: Exfiltration to Cloud Storage The threat actor attempts to exfiltrate data to a backup using Restic.
Impact T1486: Data Encrypted for Impact The threat actor attempts the deployment of ransomware after exfiltrating data.

Rapid7 Detections

For Rapid7 MDR and InsightIDR customers, the following detection rules are currently deployed and alerting against malware campaigns like the one described in this blog:

Suspicious Process – Sliver C2 Interactive Shell Execution via PowerShell
Suspicious Process – Python Start Processes in Staging Directories
Attacker Technique – Renamed PythonW.exe Executed From Non-Standard Folder
Suspicious Service: Service Installed With Command Line using Python
Network Discovery – Nltest Enumerate Domain Controllers
Attacker Technique – Potential Process Hollowing To DLLHost
Suspicious Process – Gpupdate.exe Execution With No Arguments
Suspicious Process Access – LSASS Memory Dump Using MiniDumpWriteDump Function

Indicators of Compromise

Network Based Indicators (NBIs)

Domain/IPv4 Address Notes
wnscp[.]net Typo-squatted domain, found via DNSTwist
puttyy[.]org Typo-squatted domain, found via DNSTwist
puutty[.]org Typo-squatted domain, found via DNSTwist
putyy[.]org Typo-squatted domain, found via DNSTwist
vvinscp[.]net Typo-squatted domain
winnscp[.]net Typo-squatted domain
puttty[.]org Typo-squatted domain
areauni[.]com Malicious zip archive host, likely compromised domain
mkt[.]geostrategy-ec[.]com Malicious zip archive host, likely compromised domain
fkm-system[.]com Malicious zip archive host, likely compromised domain
185.82.219[.]92 C2 address
91.92.242[.]183 C2 address
91.92.244[.]41 C2 address
91.92.249[.]106 C2 address
91.92.249[.]155 C2 address
91.92.252[.]238 C2 address
91.92.255[.]71 C2 address
91.92.255[.]77 C2 address
94.156.65[.]115 C2 address
94.156.65[.]98 C2 address
94.156.67[.]185 C2 address
94.156.67[.]188 C2 address
94.156.67[.]83 C2 address
94.158.244[.]32 C2 address

Host Based Indicators (HBIs)

File SHA256 Notes
DellAPC.exe 8b1946e3e88cff3bee6b8a2ef761513fb82a1c81f97a27f959c08d08e4c75324 Dropped by the threat actor post compromise
DellCTSW2.exe N/A Dropped by the threat actor post compromise
DellCTSWin.exe 2ee435033d0e2027598fc6b35d8d6cbca32380eb4c059ba0806b9cfb1b4275cc Dropped by the threat actor post compromise
DellPPem.exe 4b618892c9a397b2b831917264aaf0511ac1b7e4d5e56f177217902daab74a36 Dropped by the threat actor post compromise
DellPRT.exe 725aa783a0cd17df603fbe6b11b5a41c9fbfd6fc9e4f2e468c328999e5716faa Dropped by the threat actor post compromise
KeePassDR.exe c9042a7ed34847fee538c213300374c70c76436ee506273b35282c86a11d9e6a Dropped by the threat actor post compromise
NVDisplay.Contain64.exe 35161a508dfaf8e04bb6de6bc793a3840a05f2c04bbbbf8c2237abebe8e670aa Dropped by the threat actor post compromise
NVDisplay.Container64.exe 8bc39017b1ea59386f74d7c7822063b3b00315dd317f55ddc6634bde897c45c1 Dropped by the threat actor post compromise
NVDisplay.exe bbdf350c6ae2438bf14fc6dc82bb54030abf9da0c948c485e297330e08850575 Dropped by the threat actor post compromise
OktaServiceAgent.exe 28e5ee69447cea77eee2942c04009735a199771ba64f6bce4965d674515d7322 Dropped by the threat actor post compromise
OktaServiceAgent.exe f36e9dec2e7c574c07f3c01bbbb2e8a6294e85863f4d6552cccb71d9b73688ad Dropped by the threat actor post compromise
PDMVault.exe 242b2c948181f8c2543163c961775393220d128ecb38a82fa62b80893f209cab Dropped by the threat actor post compromise
PDMVault.exe 9be715df88024582eeabdb0a621477e04e2cf5f57895fa6420334609138463b9 Dropped by the threat actor post compromise
PDMVaultConf.exe 8b0d04f65a6a5a3c8fb111e72a1a176b7415903664bc37f0a9015b85d3fc0aa7 Dropped by the threat actor post compromise
PDMVaultL.exe 169ef0e828c3cd35128b0e8d8ca91fbf54120d9a2facf9eb8b57ea88542bc427 Dropped by the threat actor post compromise
PDMVaultLP.exe N/A Dropped by the threat actor post compromise
PDMVaultSec.exe 61214a7b14d6ffb4d27e53e507374aabcbea21b4dc574936b39bec951220e7ea Dropped by the threat actor post compromise
PDMVaultSecs.exe 51af3d778b5a408b725fcf11d762b0f141a9c1404a8097675668f64e10d44d64 Dropped by the threat actor post compromise
PDMVaultTest.exe 96ea33a5f305015fdd84bea48a9e266c0516379ae33321a1db16bc6fabad5679 Dropped by the threat actor post compromise
ServerController.exe 02330e168d4478a4cd2006dd3a856979f125fd30f5ed24ee70a41e03e4c0d2f8 Dropped by the threat actor post compromise
SgrmBroker.exe 8834ec9b0778a08750156632b8e74b9b31134675a95332d1d38f982510c79acb Dropped by the threat actor post compromise
VMImportHost.exe c8a982e2be4324800f69141b5be814701bcc4167b39b3e47ed8908623a13eb10 Dropped by the threat actor post compromise
VMImportHost2.exe 47ec3a1ece8b30e66afd6bb510835bb072bbccc8ea19a557c59ccdf46fe83032 Dropped by the threat actor post compromise
VMImportHost3.exe 9bd3c7eff51c5746c21cef536971cc65d25e3646533631344728e8061a0624cb Dropped by the threat actor post compromise
VMSAdmin.exe f89720497b810afc9666f212e8f03787d72598573b41bc943cd59ce1c620a861 Dropped by the threat actor post compromise
VMSAdminUtil.exe ca05485a1ec408e2f429e2e377cc5af2bee37587a2eb91dc86e8e48211ffc49e Dropped by the threat actor post compromise
VMSAdminUtilityUp.exe 972ca168f7a8cddd77157e7163b196d1267fe2b338b93dabacc4a681e3d46b57 Dropped by the threat actor post compromise
VMSBackupConfig.exe 1576f71ac41c4fc93c8717338fbc2ba48374894345c33bdf831b16d0d06df23d Dropped by the threat actor post compromise
VMSBackupUpdate.exe a5dfc9c326b1303cc1323c286ecd9751684fb1cd509527e2f959fb79e5a792c2 Dropped by the threat actor post compromise
dp_agent.exe 13B2E749EB1E45CE999427A12BB78CBEBC87C415685315C77CDFB7F64CB9AAB0 Dropped by the threat actor post compromise
local.exe bd4abc70de30e036a188fc9df7b499a19a0b49d5baefc99844dfdec6e70faf75 Dropped by the threat actor post compromise
lr_agent.exe d95f6dec32b4ebed2c45ecc05215e76bf2f520f86ad6b5c5da1326083ba72e89 Dropped by the threat actor post compromise
ntfrss.exe f36089675a652d7447f45c604e062c2a58771ec54778f6e06b2332d1f60b1999 Dropped by the threat actor post compromise
op_agent.exe 17e0005fd046e524c1681304493f0c51695ba3f24362a61b58bd2968aa1bd01a Dropped by the threat actor post compromise
pp.txt N/A Notable naming scheme
pr_agent.exe d27f9c0d761e5e1de1a741569e743d6747734d3cdaf964a9e8ca01ce662fac90 Dropped by the threat actor post compromise
python311.dll CD7D59105B0D0B947923DD9ED371B9CFC2C2AA98F29B2AFBDCD3392AD26BDE94 Malicious DLL sideloaded by setup.exe. Compiled 2024-03-05. Original name: python311_WinSCP.dll.
python311.dll 02D8E4E5F74D38C8E1C9AD893E0CEC1CC19AA08A43ECC87AC043FA825382A583 Malicious DLL sideloaded by setup.exe. Compiled 2024-04-03. Original name: python311_WinSCP.dll.
python311.dll 500574522DBCDE5E6C89803C3DCA7F857F73E0868FD7F8D2F437F3CC31CE9E8D Malicious DLL sideloaded by setup.exe. Compiled 2024-04-10. Original name: python311_Putty.dll.
-redacted-.exe a1cb8761dd8e624d6872960e1443c85664e9fbf24d3e208c3584df49bbdb2d9c Ransomware, named after the impacted domain.
readme.txt N/A Ransom note
resticORIG.exe 33f6acd3dfeda1aadf0227271937c1e5479c2dba24b4dca5f3deccc83e6a2f04 Exfil tool dropped by the threat actor
rr__agent.exe d94ed93042d240e4eaac8b1b397abe60c6c50a5ff11e62180a85be8aa0b0cc4a Dropped by the threat actor post compromise
truesight.sys bfc2ef3b404294fe2fa05a8b71c7f786b58519175b7202a69fe30f45e607ff1c AV/EDR killer, used to facilitate the execution of ransomware.
veeam.backups.shell.exe 7d53122d6b7cff81e1c5fcdb3523ccef1dbd46c93020a0de65bc475760faff7d Dropped by the threat actor post compromise
vmtools.exe ED501E49B9418FCFAF56A2EFF7ADCF85A648BDEE2C42BB09DB8C11F024667BFA Dropped by the threat actor post compromise
vmtoolsda.exe 12AFBEC79948007E87FDF9E311736160797F245857A45C040966E8E029CA97B3 Dropped by the threat actor post compromise
vmtoolsdr.exe 989A8E6A01AA20E298B1FFAE83B50CEF3E08F6B64A8F022288DC8D5729301674 Dropped by the threat actor post compromise
vmtoolsds.exe 0AA248300A9F6C498F5305AE3CB871E9EC78AE62E6D51C05C4D6DD069622F442 Dropped by the threat actor post compromise
vmtoolsdt.exe DF0213E4B784A7E7E3B4C799862DB6EA60E34D8E22EB5E72A980A8C2E9B36177 Dropped by the threat actor post compromise
DellPP.exe 51D898DE0C300CAE7A57C806D652809D19BEB3E52422A7D8E4CB1539A1E2485D Dropped by the threat actor post compromise
DellPP2.exe 8827B6FA639AFE037BB2C3F092CCB12D49B642CE5CEC496706651EBCB23D5B9E Dropped by threat actor post compromise
data.aes F18367D88F19C555F19E3A40B17DE66D4A6F761684A5EF4CDD3D9931A6655490 Encrypted Sliver beacon
data.aes C33975AA4AB4CDF015422608962BD04C893F27BD270CF3F30958981541CDFEAD
Encrypted Sliver beacon
data.aes 868CD4974E1F3AC7EF843DA8040536CB04F96A2C5779265A69DF58E87DC03029 Encrypted Sliver beacon
systemd.py 69583C4A9BF96E0EDAFCF1AC4362C51D6FF71BBA0F568625AE65A1E378F15C65 Sliver beacon loader
systemd.py 03D18441C04F12270AAB3E55F68284DCD84721D1E56B32F8D8B732A52A654D2D Sliver beacon loader
systemd.py CF82366E319B6736A7EE94CCA827790E9FDEDFACE98601F0499ABEE61F613D5D Sliver beacon loader

Using Legitimate GitHub URLs for Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/04/using-legitimate-github-urls-for-malware.html

Interesting social-engineering attack vector:

McAfee released a report on a new LUA malware loader distributed through what appeared to be a legitimate Microsoft GitHub repository for the “C++ Library Manager for Windows, Linux, and MacOS,” known as vcpkg.

The attacker is exploiting a property of GitHub: comments to a particular repo can contain files, and those files will be associated with the project in the URL.

What this means is that someone can upload malware and “attach” it to a legitimate and trusted project.

As the file’s URL contains the name of the repository the comment was created in, and as almost every software company uses GitHub, this flaw can allow threat actors to develop extraordinarily crafty and trustworthy lures.

For example, a threat actor could upload a malware executable in NVIDIA’s driver installer repo that pretends to be a new driver fixing issues in a popular game. Or a threat actor could upload a file in a comment to the Google Chromium source code and pretend it’s a new test version of the web browser.

These URLs would also appear to belong to the company’s repositories, making them far more trustworthy.

Backdoor in XZ Utils That Almost Happened

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/04/backdoor-in-xz-utils-that-almost-happened.html

Last week, the Internet dodged a major nation-state attack that would have had catastrophic cybersecurity repercussions worldwide. It’s a catastrophe that didn’t happen, so it won’t get much attention—but it should. There’s an important moral to the story of the attack and its discovery: The security of the global Internet depends on countless obscure pieces of software written and maintained by even more obscure unpaid, distractible, and sometimes vulnerable volunteers. It’s an untenable situation, and one that is being exploited by malicious actors. Yet precious little is being done to remedy it.

Programmers dislike doing extra work. If they can find already-written code that does what they want, they’re going to use it rather than recreate the functionality. These code repositories, called libraries, are hosted on sites like GitHub. There are libraries for everything: displaying objects in 3D, spell-checking, performing complex mathematics, managing an e-commerce shopping cart, moving files around the Internet—everything. Libraries are essential to modern programming; they’re the building blocks of complex software. The modularity they provide makes software projects tractable. Everything you use contains dozens of these libraries: some commercial, some open source and freely available. They are essential to the functionality of the finished software. And to its security.

You’ve likely never heard of an open-source library called XZ Utils, but it’s on hundreds of millions of computers. It’s probably on yours. It’s certainly in whatever corporate or organizational network you use. It’s a freely available library that does data compression. It’s important, in the same way that hundreds of other similar obscure libraries are important.

Many open-source libraries, like XZ Utils, are maintained by volunteers. In the case of XZ Utils, it’s one person, named Lasse Collin. He has been in charge of XZ Utils since he wrote it in 2009. And, at least in 2022, he’s had some “longterm mental health issues.” (To be clear, he is not to blame in this story. This is a systems problem.)

Beginning in at least 2021, Collin was personally targeted. We don’t know by whom, but we have account names: Jia Tan, Jigar Kumar, Dennis Ens. They’re not real names. They pressured Collin to transfer control over XZ Utils. In early 2023, they succeeded. Tan spent the year slowly incorporating a backdoor into XZ Utils: disabling systems that might discover his actions, laying the groundwork, and finally adding the complete backdoor earlier this year. On March 25, Hans Jansen—another fake name—tried to push the various Unix systems to upgrade to the new version of XZ Utils.

And everyone was poised to do so. It’s a routine update. In the span of a few weeks, it would have been part of both Debian and Red Hat Linux, which run on the vast majority of servers on the Internet. But on March 29, another unpaid volunteer, Andres Freund—a real person who works for Microsoft but who was doing this in his spare time—noticed something weird about how much processing the new version of XZ Utils was doing. It’s the sort of thing that could be easily overlooked, and even more easily ignored. But for whatever reason, Freund tracked down the weirdness and discovered the backdoor.

It’s a masterful piece of work. It affects the SSH remote login protocol, basically by adding a hidden piece of functionality that requires a specific key to enable. Someone with that key can use the backdoored SSH to upload and execute an arbitrary piece of code on the target machine. SSH runs as root, so that code could have done anything. Let your imagination run wild.

This isn’t something a hacker just whips up. This backdoor is the result of a years-long engineering effort. The ways the code evades detection in source form, how it lies dormant and undetectable until activated, and its immense power and flexibility give credence to the widely held assumption that a major nation-state is behind this.

If it hadn’t been discovered, it probably would have eventually ended up on every computer and server on the Internet. Though it’s unclear whether the backdoor would have affected Windows and macOS, it would have worked on Linux. Remember in 2020, when Russia planted a backdoor into SolarWinds that affected 14,000 networks? That seemed like a lot, but this would have been orders of magnitude more damaging. And again, the catastrophe was averted only because a volunteer stumbled on it. And it was possible in the first place only because the first unpaid volunteer, someone who turned out to be a national security single point of failure, was personally targeted and exploited by a foreign actor.

This is no way to run critical national infrastructure. And yet, here we are. This was an attack on our software supply chain. This attack subverted software dependencies. The SolarWinds attack targeted the update process. Other attacks target system design, development, and deployment. Such attacks are becoming increasingly common and effective, and also are increasingly the weapon of choice of nation-states.

It’s impossible to count how many of these single points of failure are in our computer systems. And there’s no way to know how many of the unpaid and unappreciated maintainers of critical software libraries are vulnerable to pressure. (Again, don’t blame them. Blame the industry that is happy to exploit their unpaid labor.) Or how many more have accidentally created exploitable vulnerabilities. How many other coercion attempts are ongoing? A dozen? A hundred? It seems impossible that the XZ Utils operation was a unique instance.

Solutions are hard. Banning open source won’t work; it’s precisely because XZ Utils is open source that an engineer discovered the problem in time. Banning software libraries won’t work, either; modern software can’t function without them. For years, security engineers have been pushing something called a “software bill of materials”: an ingredients list of sorts so that when one of these packages is compromised, network owners at least know if they’re vulnerable. The industry hates this idea and has been fighting it for years, but perhaps the tide is turning.

The fundamental problem is that tech companies dislike spending extra money even more than programmers dislike doing extra work. If there’s free software out there, they are going to use it—and they’re not going to do much in-house security testing. Easier software development equals lower costs equals more profits. The market economy rewards this sort of insecurity.

We need some sustainable ways to fund open-source projects that become de facto critical infrastructure. Public shaming can help here. The Open Source Security Foundation (OSSF), founded in 2022 after another critical vulnerability in an open-source library—Log4j—was discovered, addresses this problem. The big tech companies pledged $30 million in funding after the critical Log4j supply chain vulnerability, but they never delivered. And they are still happy to make use of all this free labor and free resources, as a recent Microsoft anecdote indicates. The companies benefiting from these freely available libraries need to actually step up, and the government can force them to.

There’s a lot of tech that could be applied to this problem, if corporations were willing to spend the money. Liabilities will help. The Cybersecurity and Infrastructure Security Agency’s (CISA’s) “secure by design” initiative will help, and CISA is finally partnering with OSSF on this problem. Certainly the security of these libraries needs to be part of any broad government cybersecurity initiative.

We got extraordinarily lucky this time, but maybe we can learn from the catastrophe that didn’t happen. Like the power grid, communications network, and transportation systems, the software supply chain is critical infrastructure, part of national security, and vulnerable to foreign attack. The US government needs to recognize this as a national security problem and start treating it as such.

This essay originally appeared in Lawfare.

Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader

Post Syndicated from Tom Elkins original https://blog.rapid7.com/2024/04/10/stories-from-the-soc-part-2-msix-installer-utilizes-telegram-bot-to-execute-idat-loader/

Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader

Rapid7’s Managed Detection and Response (MDR) team continuously monitors our customers’ environments, identifying emerging threats and developing new detections.

In August 2023, Rapid7 identified a new malware loader named the IDAT Loader. Malware loaders are a type of malicious software designed to deliver and execute additional malware onto a victim’s system. What made the IDAT Loader unique was the way in which it retrieved data from PNG files, searching for offsets beginning with 49 44 41 54 (IDAT).

In part one of our blog series, we discussed how a Rust based application was used to download and execute the IDAT Loader. In part two of this series, we will be providing analysis of how an MSIX installer led to the download and execution of the IDAT Loader.

While utilization of MSIX packages by threat actors to distribute malicious code is not new, what distinguished this incident was the attack flow of the compromise. Based on the recent tactics, techniques and procedures observed (TTPs), we believe the activity is associated with financially motivated threat groups.

Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader
Figure 1 – Attack Flow

MSIX Installers

In January of 2024, Red Canary released an article attributing different threat actors to various deployments of malicious MSIX installers. The MSIX installers employed a variety of techniques to deliver initial payloads onto compromised systems.

All the infections began with users navigating to typo squatted URLs after using search engines to find specific software package downloads. Typo squatting aka URL hijacking is a specific technique in which threat actors register domain names that closely resemble legitimate domain names in order to deceive users. Threat actors mimic the layout of the legitimate websites in order to lure the users into downloading their initial payloads.

Additionally, threat actors utilize a technique known as SEO poisoning, enabling the threat actors to ensure their malicious sites appear near the top of search results for users.

Technical Analysis

Typo Squatted Malvertising

In our most recent incident involving the IDAT Loader, Rapid7 observed a user downloading an installer for an application named ‘Room Planner’ from a website posing as the legitimate site. The user was searching Google for the application ‘Room Planner’ and clicked on the URL hxxps://roomplannerapp.cn[.]com. Upon user interaction, the users browser was directed to download an MSIX package, Room_Planner-x86.msix (SHA256: 6f350e64d4efbe8e2953b39bfee1040c8b041f6f212e794214e1836561a30c23).

Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader
Figure 2 – Malvertised Site for Room Planner Application

PowerShell Scripts

During execution of the MSIX file, a PowerShell script, 1.ps1 , was dropped into the folder path C:\Program Files\WindowsApps\RoomPlanner.RoomPlanner_7.2.0.0_x86__s3garmmmnyfa0\ and executed. Rapid7 determined that it does the following:

  • Obtain the IP address of the compromised asset
  • Send the IP address of the compromised asset to a Telegram bot
  • Retrieve an additional PowerShell script that is hosted on the Telegram bot
  • Delete the message containing the IP address of the compromised asset
  • Invoke the PowerShell script retrieved from the Telegram bot
Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader
Figure 3 – PowerShell script 1.ps1 contained within MSIX file Room_Planner-x86.msix

In a controlled environment, Rapid7 visited the Telegram bot hosting the next stage PowerShell script and determined that it did the following:

  • Retrieve the IP address of the compromised asset by using Invoke-RestMethod which retrieved data from the domain icanhazip[.]com
  • Enumerate the compromised assets Operating System, domain and AV products
  • Send the information to the Telegram bot
  • Create a randomly generated 8 character name, assigning it to the variable $JAM
  • Download a gpg file from URL hxxps://read-holy-quran[.]group/ld/cr.tar.gpg, saving the file to %APPDATA% saving it as the name assigned to the $JAM variable
  • Decrypt the contents of the gpg file using the passphrase ‘riudswrk’, saving them into a newly created folder named after the $JAM variable within C:\ProgramData\$JAM\cr\ as a .RAR archive file
  • Utilize tar to unarchive the RAR file
  • Start an executable named run.exe from within the newly created folder
  • Create a link (.lnk) file within the Startup folder, named after the randomly generated name stored in variable $JAM, pointing towards run.exe stored in file path C:\ProgramData\$JAM\cr\ in order to create persistence
  • Read in another PowerShell script hosted on a Pastebin site, hxxps://pastebin.pl/view/raw/a137d133 using downloadstring and execute its contents (the PowerShell script is a tool used to bypass AMSI) with IEX (Invoke-Expression)
  • Download data from URL hxxps://kalpanastickerbindi[.]com/1.jpg and reflectively load the contents and execute the program starting at function EntryPoint (indicating the downloaded data is a .NET Assembly binary)
Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader
Figure 4 – API Bot hosting PowerShell Script
Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader
Figure 5 – PowerShell AMSI Bypass Tool

After analysis of the AMSI (Anti Malware Scan Interface) bypass tool, we observed that it was a custom tool giving credit to a website, hxxps://rastamosue[.]memory-patching-amsi-bypass, which discusses how to create a program that can bypass AMSI scanning.

AMSI is a scanning tool that is designed to scan scripts for potentially malicious code after a scripting engine attempts to run the script. If the content is deemed malicious, AMSI will tell the scripting engine (in this case PowerShell) to not run the code.

RAR Contents

Contained within the RAR file were the following files:

Files Description
Dharna.7z File contains the encrypted IDAT Loader config
Guar.xslx File contains random bytes, not used during infection
Run.exe Renamed WebEx executable file, used to sideload DLL WbxTrace.dll
Msvcp140.dll Benign DLL read by Run.exe
PtMgr.dll Benign DLL read by Run.exe
Ptusredt.dll Benign DLL read by Run.exe
Vcruntime140.dll Benign DLL read by Run.exe
Wbxtrace.dll Corrupted WebEx DLL containing IDAT Loader
WCLDll.dll Benign WebEx DLL read by Run.exe

After analysis of the folder contents, Rapid7 determined that one of the DLLs, wbxtrace.dll, had a corrupted signature, indicating that its original code was tampered with. After analyzing the modified WebEx DLL, wbxtrace.dll, Rapid7 determined the DLL contained suspicious functions similar to the IDAT Loader.

Stories from the SOC Part 2: MSIX Installer Utilizes Telegram Bot to Execute IDAT Loader
Figure 6 – Analysis showing Corrupt Signature of wbxtrace.dll

Upon extracting the contents of the RAR file to the directory path C:\ProgramData\cr, the PowerShell script executes the run.exe executable.

The IDAT Loader

During execution of run.exe (a legitimate renamed WebEx executable), the executable sideloads the tampered WebEx DLL, wbxtrace.dll. Once the DLL wbxtrace.dll is loaded, the DLL executes a section of new code containing the IDAT Loader, which proceeds to read in contents from within dharna.7z.

After reading in the contents from dharna.7z, the IDAT Loader searches for the offset 49 44 41 54 (IDAT) followed by C6 A5 79 EA. After locating this offset, the loader reads in the following 4 bytes, E1 4E 91 99, which are used as the decryption key for decrypting the rest of the contents. Contained within the decrypted contents are additional code, specific DLL and Executable file paths as well as the final encrypted payload that is decrypted with a 200 byte XOR key.

The IDAT loader employs advanced techniques such as Process Doppelgänging and the Heaven’s Gate technique in order to initiate new processes and inject additional code. This strategy enables the loader to evade antivirus detections and successfully load the final stage, SecTop RAT into the newly created process, msbuild.exe.

We recently developed a configuration extractor capable of decrypting the final payload concealed within the encrypted files containing the IDAT (49 44 41 54) sections. The configuration extractor can be found on our Rapid7 Labs github page.

After using the configuration extractor, we analyzed the SecTop RAT and determined that it communicates with the IP address 91.215.85[.]66.

Rapid7 Customers

InsightIDR and Managed Detection and Response customers have existing detection coverage through Rapid7’s expansive library of detection rules. Rapid7 recommends installing the Insight Agent on all applicable hosts to ensure visibility into suspicious processes and proper detection coverage. Below is a non-exhaustive list of detections deployed and alerting on activity described:

  • Attacker Technique – Advanced Installer .MSI Executable Spawns Powershell
  • Suspicious Process – Execution From Root of ProgramData
  • Suspicious Process – PowerShell Uncommon Upper And Lower Case Combinations
  • Suspicious Process – explorer.exe in Non-Standard Location

MITRE ATT&CK Techniques

Tactics Techniques Details
Execution Command and Scripting Interpreter: PowerShell (T1059.001) 1.ps1 is used to fingerprint compromised machine and execute additional PowerShell scripts
Execution Native API (T1106) The IDAT injector and IDAT loader are using Heaven’s Gate technique to evade detection
Execution User Execution: Malicious File (T1204.002) User executes the binary Room_Planner-x86.msix
Defense Evasion Masquerading: Match Legitimate Name or Location (T1036.005) Malicious MSIX masquerades as legitimate Room Planner installer
Defense Evasion Deobfuscate/Decode Files or Information (T1140) gpg.exe used to decrypt cr.tar.gpg
Defense Evasion Hijack Execution Flow: DLL Search Order Hijacking (T1574.001) run.exe loads a malicious wbxtrace.dll
Defense Evasion Reflective Code Loading (T1620) PowerShell script loads a binary hosted at kalpanastickerbindi[.]com/1.jpg
Defense Evasion Process Injection (T1055) IDAT injector implements NtCreateSection + NtMapViewOfSection Code Injection technique to inject into cmd.exe process
Defense Evasion Process Injection: Process Doppelgänging (T1055.013) IDAT loader implements Process Doppelgänging technique to load the SecTop RAT
Defense Evasion Virtualization/Sandbox Evasion: Time Based Evasion (T1497.003) Execution delays are performed by several stages throughout the attack flow


IOC Sha256 Notes
Room_Planner-x86.msix 6f350e64d4efbe8e2953b39bfee1040c8b041f6f212e794214e1836561a30c23 Initial installer containing PowerShell scripts
1.ps1 928bd805b924ebe43169ad6d670acb2dfe45722e17d461ff0394852b82862d23 Dropped and executed by the Room_Planner-x86.msix
wbxtrace.dll 1D0DAF989CF28852342B1C0DFEE05374860E1300106FF7788BBA26D84549B845 Malicious DLL executed by run.exe, the renamed Cisco Webex binary
Dharna.7z B7469153DC92BF5DE9BF2521D9550DF21BC4574D0D0CFC919FF26D1071C000B2 Encrypted payload decrypted by wbxtrace.dll
read-holy-quran[.]group/ld/cr.tar.gpg Hosts GPG file containing RAR file
kalpanastickerbindi[.]com/1.jpg Hosts .NET executable downloaded from API Bot PowerShell script
91.215.85[.]66 SecTop RAT domain


Article URL
MSIX installer malware delivery on the rise across multiple campaigns https://redcanary.com/blog/msix-installers/
Process Doppelgänging https://malware.news/t/uncovering-the-serpent/76253
Analysis of “Heaven’s Gate” part 1 https://sachiel-archangel.medium.com/analysis-of-heavens-gate-part-1-62cca0ace6f0
Fake Update Utilizes New IDAT Loader To Execute StealC and Lumma Infostealers https://www.rapid7.com/blog/post/2023/08/31/fake-update-utilizes-new-idat-loader-to-execute-stealc-and-lumma-infostealers/
Stories from the SOC Part 1: IDAT Loader to BruteRatel https://www.rapid7.com/blog/post/2024/03/28/stories-from-the-soc-part-1-idat-loader-to-bruteratel/

XZ Utils Backdoor

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/04/xz-utils-backdoor.html

The cybersecurity world got really lucky last week. An intentionally placed backdoor in XZ Utils, an open-source compression utility, was pretty much accidentally discovered by a Microsoft engineer—weeks before it would have been incorporated into both Debian and Red Hat Linux. From ArsTehnica:

Malicious code added to XZ Utils versions 5.6.0 and 5.6.1 modified the way the software functions. The backdoor manipulated sshd, the executable file used to make remote SSH connections. Anyone in possession of a predetermined encryption key could stash any code of their choice in an SSH login certificate, upload it, and execute it on the backdoored device. No one has actually seen code uploaded, so it’s not known what code the attacker planned to run. In theory, the code could allow for just about anything, including stealing encryption keys or installing malware.

It was an incredibly complex backdoor. Installing it was a multi-year process that seems to have involved social engineering the lone unpaid engineer in charge of the utility. More from ArsTechnica:

In 2021, someone with the username JiaT75 made their first known commit to an open source project. In retrospect, the change to the libarchive project is suspicious, because it replaced the safe_fprint function with a variant that has long been recognized as less secure. No one noticed at the time.

The following year, JiaT75 submitted a patch over the XZ Utils mailing list, and, almost immediately, a never-before-seen participant named Jigar Kumar joined the discussion and argued that Lasse Collin, the longtime maintainer of XZ Utils, hadn’t been updating the software often or fast enough. Kumar, with the support of Dennis Ens and several other people who had never had a presence on the list, pressured Collin to bring on an additional developer to maintain the project.

There’s a lot more. The sophistication of both the exploit and the process to get it into the software project scream nation-state operation. It’s reminiscent of Solar Winds, although (1) it would have been much, much worse, and (2) we got really, really lucky.

I simply don’t believe this was the only attempt to slip a backdoor into a critical piece of Internet software, either closed source or open source. Given how lucky we were to detect this one, I believe this kind of operation has been successful in the past. We simply have to stop building our critical national infrastructure on top of random software libraries managed by lone unpaid distracted—or worse—individuals.

Stories from the SoC Part 1: IDAT Loader to BruteRatel

Post Syndicated from Tom Elkins original https://blog.rapid7.com/2024/03/28/stories-from-the-soc-part-1-idat-loader-to-bruteratel/

Stories from the SoC Part 1: IDAT Loader to BruteRatel

Rapid7’s Managed Detection and Response (MDR) team continuously monitors our customers’ environments, identifying emerging threats and developing new detections.

In August 2023, Rapid7 identified a new malware loader named the IDAT Loader. Malware loaders are a type of malicious software designed to deliver and execute additional malware onto a victim’s system. What made the IDAT Loader unique was the way in which it retrieved data from PNG files, searching for offsets beginning with 49 44 41 54 (IDAT).

At the time, the loader was seen being distributed via a FakeUpdates campaign. In two recent investigations, Rapid7’s Managed Detection & Response (MDR) observed the loader being used again. Based on the recent tactics, techniques and procedures observed (TTPs), we believe the activity is associated with financially motivated threat groups.

In this two-part blog series, we will examine the attack chain observed in two separate incidents, offering in-depth analysis of the malicious behavior detected. The incidents discussed in the series stem from opportunistic infections, wherein threat groups utilize malvertising and drive-by downloads in order to have their initial malicious payloads executed by users.

This first installment focuses on an incident triggered by a user downloading an application, which subsequently triggered the execution of the IDAT Loader and the BruteRatel C4 (BRC4) framework following initial access to a compromised asset.

Technical Analysis

Stage 1: The drive by

In a recent incident, Rapid7 observed a user navigate to a website that hosted popular Korean shows. Upon attempting to watch the video, the website redirected the user through various websites before ultimately directing the users browser into downloading a supposed application named AppFile_v1.1.exe. Threat actors utilize website redirection in order to make it difficult for network technologies to scan links for malicious content.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 1 – Attack Flow

Binary Analysis: Shaking off the Rust

After initial analysis of the binary AppFile_v1.1.exe, Rapid7 determined the program was written in Rust.

During execution, the program will query the name of the executable. If the executable’s name matches AppFile_v1.1.exe, the program will continue. Most sandboxes will rename the files (sometimes based on the hash) of submitted programs. This technique helps to evade sandboxes, ensuring the malicious functions are not run. If the program name does not match its original intended name,  the program will quit and display an error message, showing an image that a web page could not be loaded.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 2 – Error messages displayed by AppFile_v1.1.exe when checks fail

Next, the program will check to see if it resides within a debugger by querying the function IsDebuggerPresent. If the check passes, it will decrypt a hard-coded string that resolves to “Normal”. If not, the program will decrypt another hard-coded string that resolves to “Debugger” and then exit.

Once the anti-debug check passes, the program retrieves an encrypted string and XOR decrypts it, revealing the URL hxxps://cdn-network-services-001[.]com/update/minor/1/release.json.

The program will then perform anti-analysis techniques, specifically querying for the username and open process and comparing them to a list of known sandbox usernames and tools. The list of usernames and processes are also XOR-encrypted and are decrypted at runtime. Based on Open Source Intelligence, we determined that another malware known as Serpent Stealer contained a similar table of user names. See Appendix A below for the complete list.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Table 1 – Usernames and Known Sandbox Tools to Check Against
Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 3 – Sample Output from x64Debugger showing list of processes to check for

If any of the checks fail, the program will exit and display the message box. If the checks pass, the program will then utilize Rust library tokio-1.32.0/src/net/tcp/stream.rs in order to read in data from the decrypted URL and store the contents in memory.

Upon initial analysis, the downloaded data appeared to be encoded. Subsequently, the data is passed into a function tasked with decoding it. The decoding process involves reading each byte and subtracting the hexadecimal value 32.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 4 – Data Decoding Routine
Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 5 – Decoded downloaded bytes using CyberChef

After the downloaded data is decoded, the program XOR decrypts another string, revealing a path to the executable C:\Windows\system32\werfault.exe. Using syscalls, the program then does the following:

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Table 2 – Syscalls Used by Rust Loader

After analysis of the decoded binary, we determined that it was another executable written in Rust. The program’s executable contains a zip archive within the .rdata section. During execution, the program generates a folder with a randomly generated name in the %TEMP% directory and extracts the contents of the archive into this newly created folder.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 6 – ZIP Archive Contained Within New Rust Executable

The archive contained a DLL, msidcrl40.dll, an executable named live.exe and an encrypted file, dynatron.mdb. Initial analysis of the DLL msidcrl40.dll showed that the DLL’s signature was corrupted, indicating the DLL was tampered with. Further analysis showed that the DLL contained code related to the IDAT Loader.

IDAT Loader

After the rust program drops the contents of the zip archive, it then proceeds to execute the binary live.exe, which sideloads the DLL, msidcrl40.dll, containing the IDAT Loader code.

After the binary live.exe loads the DLL msidcrl40.dll, the DLL executes the function containing  the IDAT Loader. The IDAT then reads in encrypted contents contained within the file dynatron.mdb, searching for the offset 49 44 41 54 (IDAT) followed by C6 A5 79 EA. After decrypting the contents, the loader will then decompress the contents using RtlDecompressBuffer and execute additional code into a newly created process, cmd.exe.

The IDAT loader employs advanced techniques such as Process Doppelgänging and the Heaven’s Gate technique in order to initiate new processes and inject additional code.

The code contained within cmd.exe is responsible for decrypting the final payload and injecting it into a newly created process, msbuild.exe.

Using our IDAT Loader config extractor, we were able to extract the final payload and determined that it was SecTop RAT. During execution of the SecTop RAT, we observed that it communicated with the IP address 152.89.217[.]215.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 7 – SecTop RAT payload extracted by our IDAT Loader Python Script

Post-Exploitation: BRC4 Deployment

After the SecTop RAT was executed successfully, Rapid7 observed follow-on activity in which the threat actor executed another version of the IDAT loader from within the folder path C:\ProgramData\. We observed the following related files were dropped by the threat actor into C:\ProgramData:

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Table 2: Files Dropped by Threat Actor into C:/ProgramData\

After analysis of the files, we determined that rvm.exe was a renamed executable rvmsetup.exe, a legitimate tool that is a part of the VMWare Tools toolset. The binary is used to join a VMWare source virtual machine to an active directory domain. We also observed that the binary vmtools.dll had a corrupted signature, indicating the binary’s code was tampered with. We observed that the DLL vmtools.dll contained code related to the IDAT Loader.

During execution of the executable, rvm.exe, the program loads vmtools.dll. After vmtools.dll is loaded, the DLL is directed to execute a function that contains the IDAT Loader. The IDAT Loader proceeds to read in contents from within spank.mpg, searching for the same offset, 49 44 41 54 (IDAT) followed by C6 A5 79 EA. After decrypting the contents within spank.mpg, the IDAT Loader spawns a new process, cmd.exe, injecting additional code that is responsible for decrypting the final payload and injecting it into a newly created process, explorer.exe.

Using our static config extractor, we extracted the final payload, a 64-bit executable. During initial analysis of the final payload, we observed that the program utilized the API functions VirtualAlloc and VirtualProtect. During execution of the program, it utilized VirtualAlloc to read in and store additional code, including encrypted data, into a new region of memory. The program then called upon the function VirtualProtect, changing the newly allocated region of memory (containing the new code) to be executable. We also observed the 64 bit executable (obtained from the IDAT Loader python script) had the capability to perform process hollowing by starting a new process, notepad.exe, and injecting the code into the newly created process.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 8 – Final Payload showing Injection into notepad.exe

The newly allocated code was responsible for decrypting the encrypted data using RC4, copying the decrypted code into an allocated memory buffer via VirtualAlloc, and setting the memory buffer to have executable permission using VirtualProtect. Rapid7 determined the decrypted code was a Brute Ratel C4 (BRC4) “badger”.

Brute Ratel originated as a post-exploitation tool intended for penetration testers, designed to mimic adversary tactics as of December 2020. Its development aimed to replicate the functionality of established Command and Control (C2) software like Cobalt Strike, Mythic and Sliver. Following a successful compromise of a target, the attacker deploys the Brute Ratel “badger,” tasked with establishing communication with the attacker’s Command and Control domain.

During execution of the BRC4 program, we observed that it reached out to the domain updatenazure[.]com.

Stories from the SoC Part 1: IDAT Loader to BruteRatel
Figure 9 – Debugging BRC4 C2 Communication

After the BRC4 program was executed, we observed the threat actor attempting to enumerate the domain controller by using the command nltest /dclist.

Rapid7 Customers

InsightIDR and Managed Detection and Response customers have existing detection coverage through Rapid7’s expansive library of detection rules. Rapid7 recommends installing the Insight Agent on all applicable hosts to ensure visibility into suspicious processes and proper detection coverage. Below is a non-exhaustive list of detections deployed and alerting on activity described:

  • Network Discovery – Nltest Enumerate Domain Controllers
  • Suspicious Process – Execution From Root of ProgramData
  • Suspicious Process – PowerShell Uncommon Upper And Lower Case Combinations
  • Suspicious Process – explorer.exe in Non-Standard Location

Appendix A: Known Sandbox Usernames and Analysis Tools

Usernames Processes
hbyldjtckyn1 httpdebuggerui.exe
lubi53an14cu immunitydebugger.exe
rgzcbuyrznreg ksdumperclient.exe
8lnfaai9qdjr httpanalyzerstdv7.exe
j6sha37ka ida64.exe
keecfmwgj 32dbg.exe
pwouqdtdq 64dbg.exe
qmis5df7u protection_id.exe
txwas1m2t vmsrvc.exe
uox1tzamo x32dbg.exe
rb5bnfur2 x64dbg.exe
cm0uegn4do x96dbg.exe
douyo8rv71 prl_cc.exe
paul jones windbg.exe
pxmduopvyx scylla.exe
fnbdsldtxy idau64.exe
gexwjqdjxg idaq64.exe
gjam1nxxvm idag64.exe
jcotj17dzx taskmgr.exe
05kvauqkpqk5 procexp.exe
64f2tkiqo5k5h procmon.exe
of20xqh4vl fiddler.exe
harry johnson dumpcap.exe
4tgiizslims df5serv.exe
bvjchrpnsxn ollydbg.exe
kfu0lqwgx5p rdpclip.exe
nok4zg7zhof vmusrvc.exe
ogjb6gqgk0o5 qemu-ga.exe
xplyvzr8sgc vboxtray.exe
ykj0egq7fze vmtoolsd.exe
ryjijkiroms pestudio.exe
nzap7ubvas1 vmacthlp.exe
9yjcpseyimh procexp64.exe
uhuqiuwoefu wireshark.exe
6o4kyhhjxbir prl_tools.exe
7wjlgx7pjlw4 importrec.exe
8nl0colnq5bq vmwaretray.exe
g2dbyldgzz8yo vmwareuser.exe
pqonjhvwexsst xenservice.exe
rdhj0cnfevzxf scylla_x86.exe
xmimmckziitdl scylla_x64.exe
l3cnbb8ar5b8 vboxservice.exe

MITRE ATT&CK Techniques

Tactics Techniques Details
Initial Access Drive-by Compromise (T1189) Threat Actors utilize drive-by downloads in order to direct browsers to download their initial payloads without users consent
Execution User Execution: Malicious File (T1204.002) Users execute the binary AppFile_v1.1.exe
Execution Native API (T1106) The IDAT injector and IDAT loader are using Heaven’s Gate technique to evade detection
Defense Evasion Hijack Execution Flow: DLL Search Order Hijacking (T1574.001) run.exe loads a malicious wbxtrace.dll
Defense Evasion Process Injection (T1055) IDAT injector implements NtCreateSection + NtMapViewOfSection Code Injection technique to inject into cmd.exe process
Defense Evasion Deobfuscate/Decode Files or Information (T1140) msidcrl40.dll decrypts dynatron.mdb
Defense Evasion Process Injection: Process Doppelgänging (T1055.013) IDAT loader implements Process Doppelgänging technique to load the SecTop RAT
Defense Evasion Masquerading (T1036) dynatron.mdb file masqueraded to a .png file
Defense Evasion Virtualization/Sandbox Evasion: Time Based Evasion (T1497.003) Execution delays are performed by several stages throughout the attack flow


IOC Sha256 Notes
AppFile_v1.1.exe A3A5E7011335A2284E2D4F73FD464FF129F0C9276878A054C1932BC50608584B Rust Loader responsible for downloading IDAT Loader
msidcrl40.dll 02D5E281689EC2D4AB8AC19C93321A09113E5D8FA39380A7021580EA1887B7A5 Malicious DLL executed by live.exe
dynatron.mdb C5C52331B208CAD19DC710786E26AC55090FFCA937410D76C53569D731F0BB92 Encrypted payload decrypted by msidcrl40.dll
vmtools.dll BEFE0DF365F0E2DC05225470E45FDF03609F098A526D617C478B81AC6BB9147F Malicious DLL executed by rvm.exe
spank.mpg E05E561C5118EFDBCA113CA231C527B62E59A4BFFAE3BD374F7B4FCDD10E7D90 Encrypted payload decrypted by vmtools.dll
hxxps://cdn-network-services-001[.]com/update/minor/1/release.json Downloads additional Rust binary containing IDAT Loader
152.89.217[.]215 SecTop RAT domain
updatenazure[.]com BRC4 Domain


Article URL
Uncovering the “Serpent” https://malware.news/t/uncovering-the-serpent/76253
Process Doppelgänging https://malware.news/t/uncovering-the-serpent/76253
Analysis of “Heaven’s Gate” part 1 https://sachiel-archangel.medium.com/analysis-of-heavens-gate-part-1-62cca0ace6f0
A Deep Dive Into Malicious Direct Syscall Detection https://www.paloaltonetworks.com/blog/security-operations/a-deep-dive-into-malicious-direct-syscall-detection/
Fake Update Utilizes New IDAT Loader To Execute StealC and Lumma Infostealers https://www.rapid7.com/blog/post/2023/08/31/fake-update-utilizes-new-idat-loader-to-execute-stealc-and-lumma-infostealers/

LLM Prompt Injection Worm

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/03/llm-prompt-injection-worm.html

Researchers have demonstrated a worm that spreads through prompt injection. Details:

In one instance, the researchers, acting as attackers, wrote an email including the adversarial text prompt, which “poisons” the database of an email assistant using retrieval-augmented generation (RAG), a way for LLMs to pull in extra data from outside its system. When the email is retrieved by the RAG, in response to a user query, and is sent to GPT-4 or Gemini Pro to create an answer, it “jailbreaks the GenAI service” and ultimately steals data from the emails, Nassi says. “The generated response containing the sensitive user data later infects new hosts when it is used to reply to an email sent to a new client and then stored in the database of the new client,” Nassi says.

In the second method, the researchers say, an image with a malicious prompt embedded makes the email assistant forward the message on to others. “By encoding the self-replicating prompt into the image, any kind of image containing spam, abuse material, or even propaganda can be forwarded further to new clients after the initial email has been sent,” Nassi says.

It’s a natural extension of prompt injection. But it’s still neat to see it actually working.

Research paper: “ComPromptMized: Unleashing Zero-click Worms that Target GenAI-Powered Applications.

Abstract: In the past year, numerous companies have incorporated Generative AI (GenAI) capabilities into new and existing applications, forming interconnected Generative AI (GenAI) ecosystems consisting of semi/fully autonomous agents powered by GenAI services. While ongoing research highlighted risks associated with the GenAI layer of agents (e.g., dialog poisoning, membership inference, prompt leaking, jailbreaking), a critical question emerges: Can attackers develop malware to exploit the GenAI component of an agent and launch cyber-attacks on the entire GenAI ecosystem?

This paper introduces Morris II, the first worm designed to target GenAI ecosystems through the use of adversarial self-replicating prompts. The study demonstrates that attackers can insert such prompts into inputs that, when processed by GenAI models, prompt the model to replicate the input as output (replication), engaging in malicious activities (payload). Additionally, these inputs compel the agent to deliver them (propagate) to new agents by exploiting the connectivity within the GenAI ecosystem. We demonstrate the application of Morris II against GenAI-powered email assistants in two use cases (spamming and exfiltrating personal data), under two settings (black-box and white-box accesses), using two types of input data (text and images). The worm is tested against three different GenAI models (Gemini Pro, ChatGPT 4.0, and LLaVA), and various factors (e.g., propagation rate, replication, malicious activity) influencing the performance of the worm are evaluated.

How To Hunt For UEFI Malware Using Velociraptor

Post Syndicated from Matthew Green original https://blog.rapid7.com/2024/02/29/how-to-hunt-for-uefi-malware-using-velociraptor/

How To Hunt For UEFI Malware Using Velociraptor

UEFI threats have historically been limited in number and mostly implemented by nation state actors as stealthy persistence. However, the recent proliferation of Black Lotus on the dark web, Trickbot enumeration module (late 2022), and Glupteba (November 2023) indicates that this historical trend may be changing.

With this context, it is becoming important for security practitioners to understand visibility and collection capabilities for UEFI threats. This post covers some of these areas and presents several recent Velociraptor artifacts that can be used in the field. Rapid7 has also released a white paper providing detailed information about how UEFI malware works and some of the most common types.


Unified Extensible Firmware Interface, or UEFI, is the interface between a system’s hardware and its operating system (OS). The technology can be viewed as an updated BIOS capability to improve and add security to the boot process.

The two main types of UEFI persistence are:

  1. Serial Peripheral Interface (SPI) based
  • Firmware payload implant that is resilient to even a hard disk format.
  • Difficult to implement — there are risks associated with implementing and potentially bricking a machine if there are mistakes with the firmware.
  • Difficult to detect at scale — defenders need to extract firmware which typically requires a signed driver, then running tools for analysis.
  • Typically an analyst would dump firmware, then extract variables and other interesting files like PEs for deep dive analysis.

2. EFI System Partition (ESP) based

  • A special FAT partition that stores bootloaders and sits late in the EFI boot process.
  • Much easier to implement, only requiring root privileges and to bypass Secure Boot.
  • Does not survive a machine format.

EFI Secure Variables API visibility

EFI Secure Variables (or otherwise known as NVRAM) is how the system distributes components from the firmware during boot. From an analysis point of view, whilst dumping the firmware is difficult needing manual workflow, all operating systems provide some visibility from user space. This blog will discuss the Windows API; however, for reference Linux and macOS provides similar data.

How To Hunt For UEFI Malware Using Velociraptor

GetFirmwareEnvironmentVariable (Windows) can collect the name, namespace guid and value of EFI secure variables. This collection can be used to check current state including key/signature database and revocation.

Some of the data points it enables extracting are:

  • Platform Key (PK) — top level key.
  • Key Exchange Key (KEK)  — used to sign Signatures Database and Forbidden Signatures Database updates.
  • Signature database (db) — contains keys and/or hashes of allowed EFI binaries.
  • Forbidden signatures database (dbx) — contains keys and/or hashes of denylisted EFI binaries.
  • Other boot configuration settings.

It’s worth noting that this technique is relying on the Windows API and could be subverted with capable malware, but the visibility can provide leads for an analyst around boot configuration or signatures. There are also “boot only” NVRAM variables that can not be accessed outside boot, so a manual chip dump would need to be collected.

How To Hunt For UEFI Malware Using Velociraptor
Example of extracting EFI secure variables

Velociraptor has a community contributed capability: Generic.System.EfiSignatures. This artifact collects EFI Signature information from the client to check for unknown certificates and revoked hashes. This is a great artifact for data stacking across machines and is built by parsing data values from the efivariables() plugin.

How To Hunt For UEFI Malware Using Velociraptor

EFI System Partition (ESP) visibility

The ESP is a FAT partitioned file system that contains boot loaders and other critical files used during the boot process which do not change regularly. As such, it can be a relatively simple task to find abnormalities using forensics.

For example, parsing the File Allocation Table we can review metadata around path, timestamps, and deleted status that may provide leads for analysis.

How To Hunt For UEFI Malware Using Velociraptor
Viewing FAT metadata on *.EFI files

In the screenshot above we observe several EFI bootloader files with timestamps out of alignment. We would typically expect these files to have the same timestamps around operating system install. We can also observe deleted files and the existence of a System32 folder in the temporal range of these entries.

The EFI/ folder should be the only folder in the ESP root so querying for any paths that do not begin with EFI/ is a great hunt that detects our lead above. You can see in my screenshot below, the BlackLotus staging being bubbled to the top adding filtering for this use case.

How To Hunt For UEFI Malware Using Velociraptor
BlackLotus staging: Non ESP/ files

Interestingly, BlackLotus was known to use the Baton Drop exploit so we can compare to the publicly available Baton Drop and observe similarities to deleted files on the ESP.

How To Hunt For UEFI Malware Using Velociraptor
Publicly available Baton Drop iso contents on Github

The final component of ESP-based visibility is checking the bytes of file contents. We can run YARA to look for known malware traits, or obtain additional file type metadata that can provide leads for analysis. The screenshot below highlights the well known Black Lotus certificate information and PE header timestamp.

How To Hunt For UEFI Malware Using Velociraptor
BlackLotus PE header, suspicious Authenticode
How To Hunt For UEFI Malware Using Velociraptor
BlackLotus YARA hit in ESP

Available Velociraptor artifacts for this visibility of the ESP are:

  1. Windows.Forensics.UEFI — This artifact enables disk analysis over an EFI System Partition (ESP). The artifact queries the specified physical disk, parses the partition table to target the ESP File Allocation Table (FAT). The artifact returns file information, and PE enrichment as typical EFI files are in the PE format.
  2. Windows.Detection.Yara.UEFI This artifact expands on basic enumeration of the ESP and enables running yara over the EFI system partition.

Measured Boot log visibility

Bootkit security has always been a “race to the bottom.” If the malware could load prior to security tools, a defender would need to assume they may be defeated. Since Windows 8, Measured Boot is a feature implemented to help protect machines from early boot malware. Measured Boot checks each startup component — from firmware to boot drivers — and stores this information in the Trusted Platform Module (TPM). A binary log is then made available to verify the boot state of the machine. The default Measured Boot log location is C:\Windows\Logs\MeasuredBoot\*.log and a new file is recorded for each boot.

Windows.Forensics.UEFI.BootApplication parses Windows MeasuredBoot TCGLogs to extract PathName of events, which can assist detection of potential ESP based persistence (EV_EFI_Boot_Services_Application). The artifact leverages Velociraptor tools to deploy and execute Matt Graeber’s excellent powershell module TCGLogTools to parse TCGLogs on disk and memory.

How To Hunt For UEFI Malware Using Velociraptor

We can see when running on an infected machine that the BOOT application path has clearly changed from the default: \EFI\Microsoft\Boot\bootmgfw.efi. Therefore, Boot Application is a field that is stackable across the network.

We can also output extended values, including digest hashes for verification.

How To Hunt For UEFI Malware Using Velociraptor

Other forensic artifacts

There are many other generic forensic artifacts analysts could focus on for assisting detection of a UEFI threat. From malware network activity to unexpected errors in the event log associated with Antivirus/Security tools on the machine.

For example: BlackLotus made an effort to evade detection by changing Windows Defender access tokens to SE_PRIVILEGE_REMOVED. This technique keeps the Defender service running but effectively disables it. While Velociraptor may not have protected process privileges to check tokens directly, we can check for other indicators such as errors associated with use.

How To Hunt For UEFI Malware Using Velociraptor

Similarly, Memory integrity (HVCI) is a feature of virtualization-based security (VBS) in Windows. It provides a stronger virtualization environment via isolation and kernel memory allocations.The feature is related to Secure Boot and can be disabled for malware that needs a lower integrity environment to run. It requires setting the configuration registry key value to 0.


0 – disabled

1 – enabled
Windows.Registry.HVCI available on the artifact exchange can be used to query for this key value.

How To Hunt For UEFI Malware Using Velociraptor


Despite UEFI threats possessing intimidating capabilities, security practitioners can deploy some visibility with current tools for remote investigation. Forensically parsing disk and not relying on the Windows API, or reviewing other systemic indicators that may signal compromise, is a practical way to detect components of these threats. Knowing collection capabilities, the gaps, and how to mitigate these is just as important as knowing the threat.

In this post we have covered some of Velociraptor’s visibility for UEFI threats and we have only scratched the surface for those who know their environment and can query it effectively. Rapid7 supports Velociraptor open source, providing the community with Velociraptor and open source features unavailable even in some paid tools.


  1. ESET, Martin Smolar – BlackLotus UEFI bootkit: Myth confirmed
  2. Microsoft Incident Response – Guidance for investigating attacks using CVE-2022-21894: The BlackLotus campaign
  3. Trellix Insights: TrickBot offers new TrickBoot
  4. Palo Alto Unit 42: Diving Into Glupteba’s UEFI Bootkit
  5. Sentinel1: Moving from common sense knowledge about uefi to actually dumping uefi firmware

PIN-Stealing Android Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/01/pin-stealing-android-malware.html

This is an old piece of malware—the Chameleon Android banking Trojan—that now disables biometric authentication in order to steal the PIN:

The second notable new feature is the ability to interrupt biometric operations on the device, like fingerprint and face unlock, by using the Accessibility service to force a fallback to PIN or password authentication.

The malware captures any PINs and passwords the victim enters to unlock their device and can later use them to unlock the device at will to perform malicious activities hidden from view.

LitterDrifter USB Worm

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/11/litterdrifter-usb-worm.html

A new worm that spreads via USB sticks is infecting computers in Ukraine and beyond.

The group­—known by many names, including Gamaredon, Primitive Bear, ACTINIUM, Armageddon, and Shuckworm—has been active since at least 2014 and has been attributed to Russia’s Federal Security Service by the Security Service of Ukraine. Most Kremlin-backed groups take pains to fly under the radar; Gamaredon doesn’t care to. Its espionage-motivated campaigns targeting large numbers of Ukrainian organizations are easy to detect and tie back to the Russian government. The campaigns typically revolve around malware that aims to obtain as much information from targets as possible.

One of those tools is a computer worm designed to spread from computer to computer through USB drives. Tracked by researchers from Check Point Research as LitterDrifter, the malware is written in the Visual Basic Scripting language. LitterDrifter serves two purposes: to promiscuously spread from USB drive to USB drive and to permanently infect the devices that connect to such drives with malware that permanently communicates with Gamaredon-operated command-and-control servers.

Security Vulnerability of Switzerland’s E-Voting System

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/10/security-vulnerability-of-switzerlands-e-voting-system.html

Online voting is insecure, period. This doesn’t stop organizations and governments from using it. (And for low-stakes elections, it’s probably fine.) Switzerland—not low stakes—uses online voting for national elections. Andrew Appel explains why it’s a bad idea:

Last year, I published a 5-part series about Switzerland’s e-voting system. Like any internet voting system, it has inherent security vulnerabilities: if there are malicious insiders, they can corrupt the vote count; and if thousands of voters’ computers are hacked by malware, the malware can change votes as they are transmitted. Switzerland “solves” the problem of malicious insiders in their printing office by officially declaring that they won’t consider that threat model in their cybersecurity assessment.

But it also has an interesting new vulnerability:

The Swiss Post e-voting system aims to protect your vote against vote manipulation and interference. The goal is to achieve this even if your own computer is infected by undetected malware that manipulates a user vote. This protection is implemented by special return codes (Prüfcode), printed on the sheet of paper you receive by physical mail. Your computer doesn’t know these codes, so even if it’s infected by malware, it can’t successfully cheat you as long as, you follow the protocol.

Unfortunately, the protocol isn’t explained to you on the piece of paper you get by mail. It’s only explained to you online, when you visit the e-voting website. And of course, that’s part of the problem! If your computer is infected by malware, then it can already present to you a bogus website that instructs you to follow a different protocol, one that is cheatable. To demonstrate this, I built a proof-of-concept demonstration.

Appel again:

Kuster’s fake protocol is not exactly what I imagined; it’s better. He explains it all in his blog post. Basically, in his malware-manipulated website, instead of displaying the verification codes for the voter to compare with what’s on the paper, the website asks the voter to enter the verification codes into a web form. Since the website doesn’t know what’s on the paper, that web-form entry is just for show. Of course, Kuster did not employ a botnet virus to distribute his malware to real voters! He keeps it contained on his own system and demonstrates it in a video.

Again, the solution is paper. (Here I am saying that in 2004.) And, no, blockchain does not help—it makes security worse.

Malicious “RedAlert – Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information

Post Syndicated from Blake Darché original http://blog.cloudflare.com/malicious-redalert-rocket-alerts-application-targets-israeli-phone-calls-sms-and-user-information/

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information

On October 13, 2023, Cloudflare’s Cloudforce One Threat Operations Team became aware of a website hosting a Google Android Application (APK) impersonating the legitimate RedAlert – Rocket Alerts application (https://play.google.com/store/apps/details?id=com.red.alert&hl=en&pli=1).  More than 5,000 rockets have been launched into Israel since the attacks from Hamas began on October 7th 2023.  RedAlert – Rocket Alerts developed by Elad Nava allows individuals to receive timely and precise alerts about incoming airstrikes. Many people living in Israel rely on these alerts to seek safety – a service which has become increasingly important given the newest escalations in the region.

Applications alerting of incoming airstrikes have become targets as only days ago, Pro-Palestinian hacktivist group AnonGhost exploited a vulnerability in another application, “Red Alert: Israel” by Kobi Snir. (https://cybernews.com/cyber-war/israel-redalert-breached-anonghost-hamas/) Their exploit allowed them to intercept requests, expose servers and APIs, and send fake alerts to some app users, including a message that a “nuclear bomb is coming”. AnonGhost also claimed they attacked other rocket alert applications, including RedAlert by Elad Nava. As of October 11, 2023, the RedAlert app was reportedly functioning normally.

In the last two days, a new malicious website (hxxps://redalerts[.]me) has advertised the download of well-known open source application RedAlert by Elad Nava (https://github.com/eladnava/redalert-android). Domain impersonation continues to be a popular vector for attackers, as the legitimate website for the application (hxxps://redalert[.]me ) differs from the malicious website by only one letter. Further, threat actors continue to exploit open source code and deploy modified, malicious versions to unsuspecting users.

The malicious website hosted links to both the iOS and the Android version of the RedAlert app. But while the link to the Apple App Store referred to the legitimate version of the RedAlert app by Elad Nava, the link supposedly referring to the Android version hosted on the Play Store directly downloads a malicious APK file. This attack demonstrates the danger of sideloading applications directly from the Internet as opposed to installing applications from the approved app store.

The malicious RedAlert version imitates the legitimate rocket alert application but simultaneously collects sensitive user data. Additional permissions requested by the malicious app include access to contacts, call logs, SMS, account information, as well as an overview of all installed apps.

The website hosting the malicious file was created on October 12, 2023 and has since been taken offline. Only users who installed the Android version of the app from this specific website are impacted and urgently advised to delete the app. Users can determine if they installed the malicious version by reviewing the permissions granted to the RedAlert app. If users are unsure whether they installed the malicious version, they can delete the RedAlert applications and reinstall the legitimate version directly in the Play Store.

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
Screenshot of the attacker site https://redalerts[.]me

Malicious Android Package Kit (APK) Analysis

The malicious Android Package Kit (APK) file is installed by a user when they click the Google Play button on the fake RedAlert site. Once clicked, the user downloads the app directly from the fake site at hxxps://redalerts[.]me/app.apk. The SHA-256 hash of the APK is 5087a896360f5d99fbf4eb859c824d19eb6fa358387bf6c2c5e836f7927921c5.


A quick analysis of the AndroidManifest.xml file shows several differences compared to the legitimate, open source RedAlert application. Most notable are the additional permissions needed to collect information on the victim. The permissions added are listed below:

  • android.permission.GET_ACCOUNTS
  • android.permission.QUERY_ALL_PACKAGES
  • android.permission.READ_CALL_LOG
  • android.permission.READ_CONTACTS
  • android.permission.READ_PHONE_NUMBERS
  • android.permission.READ_PHONE_STATE
  • android.permission.READ_PRIVILEGED_PHONE_STATE
  • android.permission.READ_SMS

The application is designed to look and act like RedAlert. However, upon opening the app, a malicious service is started in the background. The startService() call is the only change to the onCreate() method, and this begins the sequence of malicious activity, which the actor has placed in a package called com.company.allinclusive.AI

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
The attacker starts their malicious code within the legitimate RedAlert code com.red.alert.activities: Main.java

The service is run to gather data from victims’ phones and upload it to the actor’s secure server. The data is extensive and includes:

  • SIM information, including IMEI and IMSI numbers, network type, country, voicemail number, PIN status, and more
  • Full Contact list
  • All SMS messages, including content and metadata for all statuses (e.g. received, outgoing, sent, etc.)
  • A list of accounts associated with the device
  • All phone calls and conversation details for including incoming, outgoing, missed, rejected, and blocked calls
  • Logged-in email and app accounts
  • List of installed applications

The actor’s code for gathering this information is illustrated below.

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
com.company.allinclusive.AI: AIMain.java contains the data the attacker will capture form the target

Stolen data is uploaded to an HTTP server at a hardcoded IP address. The actor has a Tools class which details the IP address where the data is to be uploaded:

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
com.company.allinclusive.AI: Tools.java stores the attackers command and control for the malware

Although HTTP and port 80 are specified, the actor appears to have the ability to use HTTPS and port 443 if a certificate is found bundled within the application package:

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
com.company.allinclusive.AI: UploadFileAsync.java

Data is uploaded through a Connector class, written by the actor. The Connector is responsible for encrypting the stolen data and uploading it to the HTTP server. In this sample, files are encrypted with AES in CBC mode with PKCS5 Padding. The keys are randomly generated and appended to the packaged data, however the keys are encrypted with RSA using a public key bundled in the malicious app. Because of this, anybody who is able to intercept the stolen data will be unable to decrypt it without the actor’s private key.

The encrypted files have names that look like <ID>_<DATE>.final, which contain:

  • <ID>_<DATE>.enc (encrypted data)
  • <ID>_<DATE>.param (AES encryption parameters, e.g. key and IV)
  • <ID>_<DATE>.eparam (RSA parameters, e.g. public key)

Anti-Analysis Runtime Capabilities

To avoid detection the actor included anti-analysis capabilities which can run at the time the app is started. The methods for anti-analysis that the attacker has included were anti-debugging, anti-emulation, and anti-test operations


The application makes a simple call using the builtin android.os.Debug package to see if the application is being debugged.

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
com.company.allinclusive.AI.anti.debugger: FindDebugger.java


The application attempts to locate certain files and identifiers to determine whether it is being run in an emulated environment. A snippet of these indicators are shown below:

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
com.company.allinclusive.AI.anti.emulator: FindEmulator.java checks for common emulators


The application has utilities to identify whether a test user (“monkey”) is using the application:

Malicious “RedAlert - Rocket Alerts” Application Targets Israeli Phone Calls, SMS, and User Information
com.company.allinclusive.AI.anti.monkey: FindMonkey.java

These methodologies are all rudimentary checks for whether the application is under runtime analysis. It does not, however, protect the malicious code against static analysis.

How To Detect This Malware On Your Device

If you have installed RedAlert on your device, the extraneous permissions added by the actor can be used to determine whether you have been compromised. The following permissions appearing on the RedAlert app (whether or not enabled) would indicate compromise:

  • Call Logs
  • Contacts
  • Phone
  • SMS

How To Protect Yourself

You can avoid attacks like this by following the guidance below:

  • Keep your mobile device up to date on the latest software version at all times
  • Consider using Cloudflare Teams (with Cloudflare Gateway)
  • Avoid using third party mobile application stores
  • Never install applications from Internet URLs or sideload payloads
  • Consider using for families to block malicious domains on your network




Malicious RedAlert APK Download URL


Malicious RedAlert APK Command and Control


Malicious RedAlert APK


Public key, RSA/ECB/PKCS1Padding


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Operation Triangulation: Zero-Click iPhone Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/06/operation-triangulation-zero-click-iphone-malware.html

Kaspersky is reporting a zero-click iOS exploit in the wild:

Mobile device backups contain a partial copy of the filesystem, including some of the user data and service databases. The timestamps of the files, folders and the database records allow to roughly reconstruct the events happening to the device. The mvt-ios utility produces a sorted timeline of events into a file called “timeline.csv,” similar to a super-timeline used by conventional digital forensic tools.

Using this timeline, we were able to identify specific artifacts that indicate the compromise. This allowed to move the research forward, and to reconstruct the general infection sequence:

  • The target iOS device receives a message via the iMessage service, with an attachment containing an exploit.
  • Without any user interaction, the message triggers a vulnerability that leads to code execution.
  • The code within the exploit downloads several subsequent stages from the C&C server, that include additional exploits for privilege escalation.
  • After successful exploitation, a final payload is downloaded from the C&C server, that is a fully-featured APT platform.
  • The initial message and the exploit in the attachment is deleted

The malicious toolset does not support persistence, most likely due to the limitations of the OS. The timelines of multiple devices indicate that they may be reinfected after rebooting. The oldest traces of infection that we discovered happened in 2019. As of the time of writing in June 2023, the attack is ongoing, and the most recent version of the devices successfully targeted is iOS 15.7.

No attribution as of yet.

FBI Disables Russian Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/05/fbi-disables-russian-malware.html

Reuters is reporting that the FBI “had identified and disabled malware wielded by Russia’s FSB security service against an undisclosed number of American computers, a move they hoped would deal a death blow to one of Russia’s leading cyber spying programs.”

The headline says that the FBI “sabotaged” the malware, which seems to be wrong.

Presumably we will learn more soon.

EDITED TO ADD: New York Times story.

EDITED TO ADD: Maybe “sabotaged” is the right word. The FBI hacked the malware so that it disabled itself.

Despite the bravado of its developers, Snake is among the most sophisticated pieces of malware ever found, the FBI said. The modular design, custom encryption layers, and high-caliber quality of the code base have made it hard if not impossible for antivirus software to detect. As FBI agents continued to monitor Snake, however, they slowly uncovered some surprising weaknesses. For one, there was a critical cryptographic key with a prime length of just 128 bits, making it vulnerable to factoring attacks that expose the secret key. This weak key was used in Diffie-Hellman key exchanges that allowed each infected machine to have a unique key when communicating with another machine.

PIPEDREAM Malware against Industrial Control Systems

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/05/pipedream-malware-against-industrial-control-systems.html

Another nation-state malware, Russian in origin:

In the early stages of the war in Ukraine in 2022, PIPEDREAM, a known malware was quietly on the brink of wiping out a handful of critical U.S. electric and liquid natural gas sites. PIPEDREAM is an attack toolkit with unmatched and unprecedented capabilities developed for use against industrial control systems (ICSs).

The malware was built to manipulate the network communication protocols used by programmable logic controllers (PLCs) leveraged by two critical producers of PLCs for ICSs within the critical infrastructure sector, Schneider Electric and OMRON.

CISA advisory. Wired article.