CVE-2008-5747 in F-prot Antivirus
Summary
by MITRE
F-Prot 4.6.8 for GNU/Linux allows remote attackers to bypass anti-virus protection via a crafted ELF program with a "corrupted" header that still allows the program to be executed. NOTE: due to an error in the initial disclosure, F-secure was incorrectly stated as the vendor.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 09/01/2019
The vulnerability identified as CVE-2008-5747 represents a critical flaw in F-Prot 4.6.8 for GNU/Linux that demonstrates a fundamental weakness in anti-virus signature analysis and file execution validation mechanisms. This issue specifically targets the anti-virus software's ability to properly analyze executable files, particularly those following the Executable and Linkable Format (ELF) standard used extensively in Linux systems. The flaw arises from insufficient validation of ELF file headers during the scanning process, allowing malicious actors to craft specially formatted programs that can evade detection while maintaining full functionality.
The technical implementation of this vulnerability exploits a specific condition where the ELF file header contains corrupted or modified fields that do not conform to standard specifications yet still permit successful program execution. This creates a scenario where the anti-virus engine fails to properly identify the file as potentially malicious due to its inability to correctly parse or validate the header information. The corrupted header structure bypasses the normal detection algorithms that would typically flag suspicious file characteristics, enabling the malicious program to execute without triggering anti-virus alerts. This behavior aligns with CWE-119 which addresses improper access to memory locations and improper handling of data structures.
From an operational perspective, this vulnerability presents a significant risk to Linux systems protected by F-Prot 4.6.8, as it allows attackers to execute malicious code without detection. The attack vector is particularly concerning because it requires no special privileges or complex exploitation techniques beyond creating a properly crafted ELF file. The implications extend beyond simple bypass of protection mechanisms to potentially enable more sophisticated attacks, as the malicious program can execute with full system privileges and access to all resources available to the executing user. This vulnerability directly impacts the core security promise of anti-virus solutions by allowing execution of potentially harmful code without warning or intervention.
The mitigation strategies for this vulnerability require immediate patching or upgrading of the affected F-Prot version to a patched release that properly validates ELF headers and implements more robust file analysis techniques. Organizations should also implement additional layers of security monitoring, including behavioral analysis and file integrity checking, to detect anomalous execution patterns that might indicate exploitation of this vulnerability. System administrators should consider implementing network-based intrusion detection systems that can identify suspicious file transfers or execution patterns that may indicate use of this vulnerability. The ATT&CK framework categorizes this type of vulnerability under T1055 for exploitation of vulnerabilities in software, specifically targeting anti-virus evasion techniques that allow malicious code execution without detection.
This vulnerability highlights the importance of comprehensive file format validation in security software and demonstrates how seemingly minor flaws in parsing logic can create significant security gaps. The error in initial disclosure, which incorrectly identified F-secure as the vendor, underscores the need for careful verification of vulnerability reports and proper attribution of security flaws to their correct software components. Organizations should implement regular security assessments of their anti-virus and security tooling to ensure that such fundamental validation flaws do not persist in their security infrastructure. The incident also emphasizes the necessity of maintaining up-to-date security software and the importance of vendor security response protocols in addressing vulnerabilities that could allow complete bypass of protection mechanisms.