CVE-2014-9050 in Clam
Summary
by MITRE
Heap-based buffer overflow in the cli_scanpe function in libclamav/pe.c in ClamAV before 0.98.5 allows remote attackers to cause a denial of service (crash) via a crafted y0da Crypter PE file.
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Analysis
by VulDB Data Team • 02/27/2022
The vulnerability identified as CVE-2014-9050 represents a critical heap-based buffer overflow flaw within the ClamAV antivirus software suite. This issue specifically affects the cli_scanpe function located in the libclamav/pe.c source file, which is responsible for scanning Portable Executable files. The vulnerability manifests when ClamAV processes specially crafted PE files that utilize the y0da Crypter technique, a method commonly employed by malware authors to evade detection. The flaw exists in ClamAV versions prior to 0.98.5, making a substantial portion of installations susceptible to exploitation.
The technical nature of this vulnerability stems from inadequate input validation and memory management within the PE file parsing logic. When the cli_scanpe function encounters a malformed y0da Crypter PE file, it fails to properly bounds-check memory allocations, leading to a situation where data written to heap memory exceeds the allocated buffer size. This heap-based overflow can be triggered during the parsing of PE headers and section data, causing the application to overwrite adjacent memory regions. The overflow occurs because the function does not adequately verify the size parameters of various PE structure elements, particularly those related to section headers and resource directories that are commonly manipulated by crypter tools.
The operational impact of this vulnerability extends beyond simple denial of service, as it provides remote attackers with a mechanism to crash the ClamAV scanning process without requiring any special privileges or authentication. This makes it particularly dangerous in environments where ClamAV is deployed as a network-based scanner or where automated scanning of untrusted files occurs. The crash can be reliably reproduced by simply presenting a maliciously crafted PE file to the scanner, effectively allowing an attacker to perform a denial of service attack against the antivirus system itself. This represents a significant threat to system availability and can be particularly damaging in enterprise environments where continuous protection is essential.
Organizations affected by this vulnerability should prioritize immediate remediation through the upgrade to ClamAV version 0.98.5 or later, which includes patches addressing the buffer overflow conditions in the cli_scanpe function. The fix typically involves implementing proper bounds checking and memory allocation validation within the PE parsing routines. Security administrators should also consider implementing additional monitoring and alerting mechanisms to detect potential exploitation attempts, particularly in environments where automated file scanning is performed on untrusted content. This vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a technique that could be leveraged by attackers following ATT&CK tactics such as T1499.004 for network denial of service operations. Organizations should also review their file scanning policies to ensure that potentially malicious PE files are quarantined or handled appropriately to prevent exploitation attempts.