CVE-2004-2075 in Sophos
Summary
by MITRE
Sophos Anti-Virus 3.78 allows remote attackers to cause a denial of service (infinite loop) via a MIME header that is not properly terminated.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability identified as CVE-2004-2075 represents a significant denial of service weakness in Sophos Anti-Virus version 3.78 that stems from improper handling of MIME headers during email scanning processes. This flaw specifically manifests when the antivirus software encounters MIME headers that lack proper termination sequences, creating a condition where the parsing mechanism enters an infinite loop. The issue occurs within the email content inspection functionality that Sophos employs to scan incoming messages for malicious content, making it particularly dangerous in network environments where email traffic is prevalent.
From a technical perspective, the vulnerability exploits a classic buffer handling error where the software's MIME parser fails to properly validate header termination sequences. When processing email messages, Sophos Anti-Virus attempts to parse MIME headers to determine message structure and content type, but the parser does not adequately check for proper header termination. This allows an attacker to craft malicious email messages containing malformed MIME headers that cause the parsing routine to continuously loop without making progress, ultimately consuming system resources and rendering the antivirus service unavailable. The infinite loop behavior directly maps to CWE-835, which specifically addresses the issue of infinite loops in software implementations, and represents a fundamental failure in input validation and error handling within the email scanning component.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively disable email security services on affected systems. Network administrators who rely on Sophos Anti-Virus for email protection face the risk of complete email service outages when malicious actors exploit this weakness, potentially affecting business continuity and communication workflows. The vulnerability is particularly concerning because it can be triggered through simple email transmission without requiring any special privileges or complex attack vectors, making it accessible to a wide range of threat actors. This characteristic aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how a seemingly minor parsing flaw can result in significant operational disruptions.
Mitigation strategies for CVE-2004-2075 should prioritize immediate software updates to the latest available versions of Sophos Anti-Virus where the vulnerability has been addressed through proper header validation and termination sequence checking. System administrators should implement additional email filtering measures that can identify and quarantine suspicious MIME header structures before they reach the antivirus scanning layer. Network monitoring should be enhanced to detect unusual CPU utilization patterns that might indicate the infinite loop behavior, and incident response procedures should be established to quickly address potential exploitation attempts. Organizations should also consider implementing redundant email security measures and maintaining offline backup communication channels to ensure business continuity during potential exploitation events. The vulnerability underscores the importance of robust input validation in security software and highlights the critical need for thorough testing of parsing routines against malformed data inputs to prevent similar issues in other security applications.