CVE-2006-0994 in Sophos
Summary
by MITRE
Multiple Sophos Anti-Virus products, including Anti-Virus for Windows 5.x before 5.2.1 and 4.x before 4.05, when cabinet file inspection is enabled, allows remote attackers to execute arbitrary code via a CAB file with "invalid folder count values," which leads to heap corruption.
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Analysis
by VulDB Data Team • 08/01/2019
The vulnerability identified as CVE-2006-0994 represents a critical heap corruption flaw affecting multiple Sophos Anti-Virus products including versions 5.x before 5.2.1 and 4.x before 4.05. This security issue specifically manifests when the software performs cabinet file inspection, a common technique used to analyze compressed archive files for potential threats. The flaw stems from insufficient input validation mechanisms within the CAB file parsing logic, creating a pathway for malicious actors to exploit the software's handling of malformed archive structures.
The technical exploitation occurs through carefully crafted CAB files containing invalid folder count values that cause the anti-virus engine to improperly allocate memory resources during file processing. When the software encounters these malformed folder count indicators, it fails to properly validate the data structure before proceeding with heap allocation operations. This validation failure results in heap corruption conditions where attacker-controlled data can overwrite critical memory locations, potentially allowing arbitrary code execution with the privileges of the anti-virus process. The vulnerability falls under CWE-122 heap-based buffer overflow, which is classified as a high-severity issue in the Common Weakness Enumeration catalog.
Operationally, this vulnerability presents significant risks to organizations relying on Sophos Anti-Virus solutions, as remote attackers can potentially execute malicious code without requiring local system access. The attack vector involves delivering a specially crafted CAB file through various means including email attachments, web downloads, or removable media, making it particularly dangerous in enterprise environments where anti-virus software operates with elevated privileges. The heap corruption aspect means that successful exploitation could lead to complete system compromise, as the memory corruption can be leveraged to execute arbitrary commands or establish persistence mechanisms within the target environment.
The impact of this vulnerability extends beyond immediate code execution capabilities, as it can potentially be chained with other exploits to bypass security controls such as DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization). Security researchers have noted that the exploitation of such heap-based vulnerabilities often requires sophisticated techniques to achieve reliable code execution, but the potential for privilege escalation makes it particularly concerning for enterprise security teams. Organizations using affected Sophos versions should immediately implement patches and updates to address this vulnerability, while also considering network segmentation and monitoring for suspicious CAB file activity.
Mitigation strategies for CVE-2006-0994 should include immediate deployment of Sophos patches addressing the heap corruption issue, along with implementation of network-based controls to block suspicious CAB file transfers. Security teams should also consider disabling cabinet file inspection functionality where possible, as this reduces the attack surface for exploitation. Additionally, monitoring for unusual memory allocation patterns and implementing robust application whitelisting policies can help detect and prevent exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory management in security software, as flaws in anti-virus engines can be exploited to compromise entire systems. This issue aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute malicious code through compromised anti-virus processes.