Today’s Topics:
- WinRAR Vulnerability Enables Mark of the Web Bypass and Silent Code Execution
- Carding Tool Abusing WooCommerce API Downloaded 34,000 Times on PyPI
- How can Netizen help?
WinRAR Vulnerability Enables Mark of the Web Bypass and Silent Code Execution
A newly disclosed vulnerability in the popular file archiver WinRAR allows attackers to bypass Windows’ built-in Mark of the Web (MotW) protections, enabling the stealthy execution of potentially malicious code. Tracked as CVE-2025-31334, the flaw affects all versions of WinRAR prior to the latest release, version 7.11.
Mark of the Web is a Windows security feature that flags files downloaded from the internet by tagging them with an alternate data stream called Zone.Identifier. When a user attempts to run a file tagged with MotW, Windows displays a security warning, prompting the user to confirm whether the file should be executed. This helps prevent accidental execution of malware and is one of the OS’s primary mechanisms for defending against internet-delivered threats.
The issue in WinRAR arises when a symbolic link (symlink) is embedded within an archive. If the symlink points to an executable file and the archive is opened using the WinRAR shell, the MotW flag is ignored entirely—even if the original file was downloaded from the internet and should have triggered a security warning.
This means an attacker could craft an archive containing a symlink to a malicious executable and distribute it online. When the user extracts and runs the file using WinRAR, the system would execute the code without any MotW-based warning.
It’s important to note that creating a symlink on a Windows system requires administrator-level permissions. While this adds some friction, it does not fully mitigate the risk—particularly in environments with weak privilege separation or systems already compromised in earlier stages of an attack.
The vulnerability has been rated with a CVSS score of 6.8, placing it in the medium severity range. The bug was responsibly disclosed to WinRAR’s developer RARLAB by researcher Shimamine Taihei of Mitsui Bussan Secure Directions. The coordination was managed through Japan’s Information Technology Promotion Agency (IPA) and Japan’s Computer Security Incident Response Team (JPCERT/CC).
WinRAR’s changelog for version 7.11 notes the fix simply:
“If symlink pointing at an executable was started from WinRAR shell, the executable Mark of the Web data was ignored.”
MotW bypasses have been increasingly targeted by both criminal and state-sponsored threat actors in recent years. Similar tactics have been used in other compression tools. For example, Russian cybercriminals recently exploited a bug in 7-Zip that failed to propagate MotW when using double compression techniques—allowing them to deploy malware like Smokeloader without triggering Windows alerts.
MotW bypasses are attractive to attackers because they help sidestep one of the final lines of defense in environments where users download and open untrusted files. These flaws are especially valuable in phishing campaigns, drive-by downloads, or watering hole attacks.
SOC teams should prioritize upgrading all endpoints to WinRAR 7.11 or later to ensure MotW tags are honored properly during archive extraction. While the CVSS score might not immediately suggest a critical risk, the potential to disable a key Windows security feature in user-facing workflows makes this bug particularly attractive to attackers focused on social engineering.
Security teams should also monitor for symlink usage within archive contexts, especially in user-writable directories. Consider implementing detection logic for non-standard execution paths involving archive tools, and review telemetry for execution of binaries extracted from archives that should have been flagged with MotW.
Lastly, this vulnerability serves as a reminder that endpoint protection strategies should not rely solely on operating system features like MotW. Defense-in-depth approaches—including behavior-based monitoring, application allowlisting, and user training—remain essential, especially when commonly used utilities like WinRAR can be used to subvert expected safeguards.
Carding Tool Abusing WooCommerce API Downloaded 34,000 Times on PyPI
A malicious Python package designed to validate stolen credit cards using legitimate WooCommerce stores has been downloaded more than 34,000 times from the Python Package Index (PyPI), highlighting the ongoing abuse of open-source ecosystems in support of cybercrime. The package, named disgrasya, was discovered by researchers at Socket and has since been removed from the repository—but not before it enabled wide-scale carding activity through automated abuse of online stores.
Unlike typical supply chain attacks that rely on deception or typo-squatting to trick developers into installing fake libraries, the disgrasya package made no effort to disguise its purpose. In fact, the PyPI listing clearly stated: “A utility for checking credit cards through multiple gateways using multi-threading and proxies.” This bold description signaled that the authors weren’t concerned with flying under the radar, using PyPI as a high-traffic distribution platform to reach carding actors across the globe.
According to Socket’s analysis, the malicious behavior was introduced in version 7.36.9—likely an intentional move to bypass security scans that are stricter for initial submissions. By delaying the addition of malicious code until a later version, attackers may have evaded automated analysis tools and code reviewers.
The script targets WooCommerce stores that use the CyberSource payment gateway, a common configuration for online businesses. The tool automates a process that would normally require human interaction by programmatically emulating a full online shopping session.
Here’s how the attack works:
- The script crawls legitimate WooCommerce stores and collects product IDs.
- It adds those products to a shopping cart using the site’s backend API.
- It moves to the checkout page and harvests critical session data: a CSRF token and a capture context, which is a dynamic key used by CyberSource to tokenize credit card data securely.
- Instead of sending the credit card details directly to CyberSource, the script transmits them to an attacker-controlled server (
railgunmisaka.com), which mimics the payment gateway and returns a fake token. - That token is used to complete the checkout process on the WooCommerce site. If the transaction goes through, the card is logged as valid; if not, it’s discarded and the next card in the list is tested.
This method allows the actor to verify thousands of stolen credit card numbers in a short time while leveraging legitimate infrastructure to avoid detection.
Socket points out that this workflow is methodical, difficult to detect, and designed to blend into normal site activity. It’s particularly dangerous for merchants because traditional anti-fraud systems often can’t distinguish these fake checkouts from legitimate customer behavior—especially when the tool simulates a complete transaction path.
Detection becomes even harder when attackers use proxies or botnets to distribute traffic across different IPs and regions, further mimicking normal web usage patterns.
Though detection is difficult, there are several ways to make life harder for carding actors:
- Block transactions under a certain threshold (e.g., <$5), which are commonly used for validation attempts.
- Monitor for checkout patterns with high failure rates or sudden spikes in low-value orders.
- Apply rate limits on checkout endpoints to slow down automated attacks.
- Add CAPTCHA challenges during checkout to interrupt script-based submissions.
- Track behavioral anomalies tied to repeated access from the same IP or region.
Merchants using WooCommerce, especially those with CyberSource integration, should consider reviewing their site logs for suspicious automated checkout activity and audit past orders for signs of carding.
Security teams should review web application logs for e-commerce properties to detect suspicious activity related to automated card validation. Look for checkout patterns involving low-value transactions, high error rates, or repeated requests originating from a limited IP pool. Integration monitoring tools and fraud prevention services should be configured to flag checkout endpoints for behavioral anomalies. SOC analysts should also ensure that payment APIs are not being indirectly abused through backend channels and should validate that session and payment token endpoints are not being exposed to external manipulation.
Finally, any organization distributing Python packages internally or externally should closely monitor updates for malicious behavior introduced in later versions of a package—especially those with no clear use case or documentation.
How Can Netizen Help?
Netizen ensures that security gets built-in and not bolted-on. Providing advanced solutions to protect critical IT infrastructure such as the popular “CISO-as-a-Service” wherein companies can leverage the expertise of executive-level cybersecurity professionals without having to bear the cost of employing them full time.
We also offer compliance support, vulnerability assessments, penetration testing, and more security-related services for businesses of any size and type.
Additionally, Netizen offers an automated and affordable assessment tool that continuously scans systems, websites, applications, and networks to uncover issues. Vulnerability data is then securely analyzed and presented through an easy-to-interpret dashboard to yield actionable risk and compliance information for audiences ranging from IT professionals to executive managers.
Netizen is a CMMI V2.0 Level 3, ISO 9001:2015, and ISO 27001:2013 (Information Security Management) certified company. We are a proud Service-Disabled Veteran-Owned Small Business that is recognized by the U.S. Department of Labor for hiring and retention of military veterans.
