CVE-2008-6846 in avast
Summary
by MITRE
Multiple stack-based buffer overflows in avast! Linux Home Edition 1.0.5, 1.0.5-1, and 1.0.8 allow remote attackers to cause a denial of service (application crash) or execute arbitrary code via a malformed (1) ISO or (2) RPM file.
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Analysis
by VulDB Data Team • 11/18/2018
The vulnerability identified as CVE-2008-6846 represents a critical security flaw in avast! Linux Home Edition versions 1.0.5, 1.0.5-1, and 1.0.8 that exposes the software to remote code execution and denial of service attacks through improper input validation. This issue stems from stack-based buffer overflows that occur when the antivirus software processes malformed ISO and RPM files, creating a significant attack surface for malicious actors seeking to compromise systems running these vulnerable versions.
The technical implementation of this vulnerability manifests as stack-based buffer overflows within the file parsing routines of the avast! antivirus engine. When processing specially crafted ISO or RPM files, the software fails to properly validate input lengths and buffer boundaries, allowing attackers to overflow memory buffers and potentially overwrite critical program execution data. This flaw operates under the common weakness enumeration CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking permits memory corruption. The vulnerability specifically impacts the software's ability to handle malformed archive structures, where the parsing logic does not adequately validate the size and format of file headers and metadata sections.
From an operational perspective, this vulnerability creates a severe risk for systems running affected avast! versions, as remote attackers can leverage the buffer overflows to either crash the antivirus application completely or execute arbitrary code with the privileges of the running process. The attack vector requires remote delivery of malicious ISO or RPM files, making it particularly dangerous in environments where automated file processing occurs or where users may encounter infected files through legitimate software distribution channels. The impact extends beyond simple application instability to potential system compromise, as successful exploitation could enable attackers to gain unauthorized access to system resources and execute malicious payloads.
The exploitation of this vulnerability aligns with techniques described in the attack tactics and techniques framework, particularly those related to privilege escalation and code execution through software vulnerabilities. The flaw demonstrates how security tools themselves can become attack vectors when not properly hardened against malformed input processing. Organizations utilizing these vulnerable versions face significant risk of unauthorized system access and potential data breaches, as the antivirus software that should protect against such threats becomes a potential entry point for attackers. The vulnerability also highlights the importance of proper input validation and memory management practices in security software, where the protective mechanisms can inadvertently create exploitable conditions.
Mitigation strategies for CVE-2008-6846 should prioritize immediate patching of affected avast! Linux Home Edition versions to the latest available releases that contain proper bounds checking and input validation fixes. System administrators should implement network segmentation and file filtering measures to prevent automatic processing of potentially malicious ISO and RPM files, particularly in environments where the vulnerable software operates. Additionally, organizations should conduct comprehensive vulnerability assessments to identify any other instances of the same or similar buffer overflow patterns within their antivirus and security tooling portfolios, as this vulnerability demonstrates how security tools can themselves contain exploitable code. The remediation process should include thorough testing of updated software versions to ensure that the buffer overflow protections do not introduce compatibility issues with legitimate file processing requirements.