CVE-2005-4680 in Sophos
Summary
by MITRE
Sophos Anti-Virus before 4.02, 4.5.x before 4.5.9, 4.6.x before 4.6.9, and 5.x before 5.1.4 allow remote attackers to hide arbitrary files and data via crafted ARJ archives, which are not properly scanned.
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Analysis
by VulDB Data Team • 07/16/2018
The vulnerability described in CVE-2005-4680 represents a significant weakness in Sophos Anti-Virus software across multiple version ranges, specifically affecting versions prior to 4.02, 4.5.9, 4.6.9, and 5.1.4. This flaw enables remote attackers to exploit the archive scanning capabilities of the antivirus solution by crafting malicious ARJ archives that bypass detection mechanisms. The vulnerability stems from insufficient validation and processing of ARJ archive structures, allowing attackers to conceal malicious content within these compressed files.
The technical implementation of this vulnerability involves the improper handling of ARJ archive formats during the scanning process. ARJ archives are compressed file containers that can contain multiple files and directories, and the flaw occurs when Sophos Anti-Virus fails to properly parse or validate the metadata within these archives. Attackers can craft ARJ files with specific header structures and compression parameters that cause the antivirus engine to skip or misinterpret the contents, effectively hiding malicious payloads from detection. This represents a classic case of archive unpacking and content inspection bypass, where the security solution fails to properly examine all components of compressed files.
From an operational impact perspective, this vulnerability creates a substantial risk for organizations relying on Sophos Anti-Virus for endpoint protection. Remote attackers can leverage this weakness to deliver malware, backdoors, or other malicious payloads through seemingly benign ARJ archives that pass through security screening. The implications extend beyond simple file concealment, as attackers can potentially use this technique to evade network-based detection systems, bypass application whitelisting controls, and maintain persistence within compromised environments. The vulnerability also undermines the fundamental trust in antivirus solutions to properly scan and detect threats within compressed file formats.
The attack vector for this vulnerability is particularly concerning as it operates over remote networks, allowing attackers to craft malicious ARJ archives and distribute them through various channels including email attachments, file sharing systems, or web downloads. This aligns with ATT&CK technique T1070.004 for "File Deletion" and T1204.002 for "User Execution" where the malicious archive serves as a delivery mechanism for additional payloads. The vulnerability also relates to CWE-20, "Improper Input Validation," and CWE-470, "Use of Externally-Controlled Input for Path or Filename," as the software fails to properly validate archive contents and potentially allows manipulation of file paths or content structures.
Organizations should implement immediate mitigations including updating to patched versions of Sophos Anti-Virus software, implementing additional layers of security such as application control policies, and establishing network monitoring for suspicious ARJ archive traffic. Security teams should also consider implementing sandboxing mechanisms for suspicious compressed files and conducting regular vulnerability assessments to identify similar weaknesses in other security solutions. The remediation process should include comprehensive testing of updated antivirus signatures and ensuring that all endpoints are properly patched to prevent exploitation of this vulnerability.