A purported zero-day exploit affecting the widely used 7-Zip file compression utility has come under scrutiny, initially credited to an anonymous hacker known as “NSA_Employee39” on the social platform X. This alleged exploit was claimed to leverage a security vulnerability, CVE-2024-11477, purportedly allowing attackers to execute arbitrary code on a target’s system when a malicious archive file is opened or extracted using the latest version of 7-Zip.
Overview of the Alleged Zero-Day Vulnerability
The purported exploit supposedly targets the LZMA decoder component in 7-Zip, specifically by triggering a buffer overflow in the RC_NORM function through a deliberately malformed LZMA stream. This alleged exploitation would permit the execution of arbitrary code by manipulating buffer pointers and payload alignment, ultimately allowing attackers to compromise a victim’s system with minimal user interaction—merely by opening or extracting a malicious .7z file.
To support the authenticity of the exploit, “NSA_Employee39” posted a proof-of-concept on Pastebin, demonstrating a benign payload that launches the Windows Calculator application (calc.exe). However, this benign code could easily be replaced with more malicious intent, significantly magnifying the potential threat. The ramifications are particularly concerning considering Infostealer malware, which aims to extract sensitive information such as login credentials and banking data from infected systems. Infostealers typically employ social engineering tactics, like using password-protected .rar or .zip files to evade antivirus detection. This new exploit, however, eliminates the need for such methods, posing an immediate and simplified risk to unsuspecting users.
Potential Risks and Impact on Supply Chains
The risk posed by this alleged vulnerability extends significantly beyond individual users, raising substantial concerns within supply chain contexts where automated workflows often process files from external sources. Weaponized .7z files could infiltrate these processes, potentially embedding undetected malicious payloads that activate within enterprise systems. Such scenarios could lead to serious consequences, including data breaches, ransomware attacks, and operational disruptions within organizations.
While the exploitation of this vulnerability might seem conceptually straightforward, it demands substantial technical expertise. Skilled adversaries could craft shellcode to function within a constrained byte space, amplifying the threat’s credibility and concern. Although creating effective shellcode is challenging, it is not impossible for experienced hackers, thus raising the alarm about the potential for real-world attacks.
Lack of Responsible Disclosure and Further Threats
One of the critical issues highlighted by the release of this purported zero-day exploit is the lack of responsible disclosure. Unlike officially reported vulnerabilities, public disclosures without prior notice provide immediate exploitation opportunities for attackers. This kind of release bypasses the process where developers can address and patch vulnerabilities before they are widely known.
Moreover, “NSA_Employee39” hinted at the imminent release of another zero-day exploit, this time targeting MyBB, an open-source forum software. This threat could potentially expose sensitive databases of numerous online communities to significant risks, further underscoring the importance of responsible disclosure practices in cybersecurity.
In the absence of an official patch, cybersecurity experts have urgently advised several precautionary measures. These include closely monitoring for updates from 7-Zip’s developers and promptly implementing patches when available. Additionally, adopting file sandboxing and thorough scanning to scrutinize third-party files before processing them is recommended. Conducting user training to educate employees about the dangers of opening unsolicited or suspicious files is another crucial step. Finally, encouraging collaboration among cybersecurity professionals can help analyze and counteract emerging threats more effectively.
Response and Denial from 7-Zip Developer
Igor Pavlov, the creator of 7-Zip, responded to the claims on the 7-Zip discussion forum, firmly dismissing the allegations. He stated there is no ACE vulnerability in 7-Zip/LZMA as claimed. Following this, further updates from “@NSA_Employee39” on Pastebin reiterated that the exploit stemmed from inadequate validation in the LZMA stream structure, yet did not provide conclusive evidence to support this claim.
Adding another layer to the discussion, cybersecurity researcher Marc R. from Kaspersky conducted a thorough analysis and dismissed the exploit’s efficacy. Detailed examination revealed that malformed LZMA streams trigger errors rather than overflow vulnerabilities, demonstrating a robust handling mechanism within 7-Zip. Furthermore, the shellcode and offsets provided in the proof of concept were deemed non-functional, labeling the exploit as ineffective.
Validation and Further Analysis
A supposed zero-day exploit targeting the widely utilized 7-Zip file compression software has recently come under investigation. This alleged exploit, originally disclosed by an anonymous hacker known by the pseudonym “NSA_Employee39” on the social media platform X, reportedly takes advantage of a security flaw identified as CVE-2024-11477. According to the claims, this vulnerability allows attackers to execute arbitrary code on the victim’s system when a malicious archive file is opened or extracted using the latest version of 7-Zip.
Security experts are deeply scrutinizing these claims to understand the potential risks. If proven accurate, such a vulnerability could pose significant threats, given the extensive use of 7-Zip in various industries and personal computing. Users and administrators are urged to stay alert for any official updates or patches from 7-Zip’s developers. Meanwhile, practicing caution with unknown or suspicious archive files is highly recommended to mitigate potential security breaches until a confirmed fix is available.
