CVE-2004-1909 in ClamAV
Summary
by MITRE
Claim Anti-Virus (ClamAV) 0.68 and earlier allows remote attackers to cause a denial of service (crash) via certain RAR archives, such as those generated by the Beagle/Bagle worm.
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Analysis
by VulDB Data Team • 06/30/2021
The vulnerability identified as CVE-2004-1909 affects Claim Anti-Virus version 0.68 and earlier, representing a significant denial of service weakness in the ClamAV antivirus engine. This flaw specifically manifests when processing certain RAR archives that are crafted to exploit memory handling issues within the decompression routines. The vulnerability becomes particularly dangerous when these malicious archives are generated by the Beagle/Bagle worm, which was one of the most prolific malware families of that era. The attack vector involves remote exploitation through the processing of specially crafted RAR files that trigger buffer overflows or memory corruption conditions within the ClamAV scanning engine.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within ClamAV's RAR archive handling code. When the antivirus engine attempts to decompress or analyze these malicious RAR archives, it encounters malformed data structures that cause the application to crash or become unresponsive. This occurs because the decompression algorithm fails to properly handle certain edge cases in the RAR file format, particularly those that involve corrupted or oversized data blocks. The flaw operates at the core level of the antivirus engine where archive extraction and content analysis take place, making it particularly effective as a denial of service mechanism that can be triggered without requiring authentication or special privileges.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a potential attack surface that could be exploited in larger campaign contexts. Attackers leveraging this weakness could cause widespread disruption by sending infected RAR files to multiple targets, effectively rendering the antivirus protection useless during the attack window. The vulnerability particularly affects systems that rely heavily on automated scanning of incoming files, such as email servers, file sharing systems, and network security appliances that use ClamAV for content inspection. The crash conditions can result in complete service outages, requiring system administrators to restart services and potentially lose scanning capabilities until the vulnerability is patched.
Security practitioners should recognize this vulnerability as a classic example of improper input validation that aligns with CWE-121, which covers stack-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read vulnerabilities. The attack pattern corresponds to techniques described in the ATT&CK framework under T1499, specifically targeting the availability of systems through service disruption. Organizations should implement immediate mitigation strategies including updating to ClamAV versions 0.69 or later where this vulnerability has been resolved, implementing network-based filtering to block suspicious RAR files, and establishing monitoring protocols to detect unusual scanning behavior that might indicate exploitation attempts. Additionally, administrators should consider implementing sandboxing techniques for suspicious file analysis to prevent direct exploitation of the vulnerability in production environments.