CVE-2007-3875 in Unicenter Network And Systems Management
Summary
by MITRE
arclib.dll before 7.3.0.9 in CA Anti-Virus (formerly eTrust Antivirus) 8 and certain other CA products allows remote attackers to cause a denial of service (infinite loop and loss of antivirus functionality) via an invalid "previous listing chunk number" field in a CHM file.
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Analysis
by VulDB Data Team • 12/31/2016
The vulnerability identified as CVE-2007-3875 represents a critical denial of service flaw within CA Anti-Virus software, specifically affecting versions prior to 7.3.0.9 of the arclib.dll component. This issue manifests when the software processes CHM (Compiled HTML Help) files that contain malformed data structures, creating a condition where the antivirus engine becomes trapped in an infinite loop. The flaw stems from inadequate input validation mechanisms within the CHM file parsing functionality, particularly when handling the "previous listing chunk number" field. This field is part of the CHM file format's internal structure used for organizing and linking help content, but when improperly set, it triggers a cascading failure in the antivirus processing logic.
The technical exploitation of this vulnerability occurs through the manipulation of CHM file attributes, specifically targeting the chunk numbering system that governs how help content is organized within the compressed archive format. When the arclib.dll component encounters a CHM file with an invalid previous listing chunk number, the parsing routine enters a recursive or iterative loop where it continuously references invalid memory locations or repeatedly processes the same data structures. This creates a resource exhaustion scenario that effectively disables the antivirus functionality, rendering the system vulnerable to actual malware attacks while the security software remains non-operational. The vulnerability operates at the file parsing layer, making it particularly dangerous as it can be triggered by simply opening or scanning a malicious CHM file, regardless of the user's interaction level.
The operational impact of this vulnerability extends beyond simple service disruption to create a significant security gap in enterprise environments where CA Anti-Virus is deployed. Organizations using affected versions face the risk of complete antivirus system failure, leaving their networks exposed to malware threats while the security infrastructure appears to be operational but is actually unresponsive. This situation creates a false sense of security that can lead to extended periods of vulnerability, as administrators may not immediately recognize that their protection systems are compromised. The infinite loop condition can consume significant system resources including CPU cycles and memory, potentially causing system instability or performance degradation across multiple endpoints. The vulnerability is particularly concerning in corporate environments where CHM files might be encountered through legitimate business processes, such as help documentation for software applications, making the attack surface broader than initially apparent.
Mitigation strategies for CVE-2007-3875 primarily focus on immediate software updates and version control measures. Organizations should prioritize upgrading to CA Anti-Virus versions 7.3.0.9 or later, where the arclib.dll component has been patched to properly validate CHM file structures before processing. System administrators should implement network monitoring to detect potential exploitation attempts through CHM file transfers, as the vulnerability can be triggered remotely via malicious file downloads or email attachments. The implementation of file type restrictions and content filtering can help prevent the execution of CHM files from untrusted sources, reducing the attack surface. Security teams should also consider deploying additional layers of protection such as sandboxing mechanisms for suspicious file processing, which can isolate potentially malicious CHM files before they reach the antivirus engine. This vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and can be mapped to ATT&CK technique T1059.007 for execution through help files and T1499.004 for denial of service attacks. Organizations should also conduct regular vulnerability assessments to identify other potentially affected CA products and ensure comprehensive patch management across their entire security infrastructure.