CVE-2005-2450 in ClamAV
Summary
by MITRE
Multiple integer overflows in the (1) TNEF, (2) CHM, or (3) FSG file format processors in libclamav for Clam AntiVirus (ClamAV) 0.86.1 and earlier allow remote attackers to gain privileges via a crafted e-mail message.
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Analysis
by VulDB Data Team • 07/05/2021
The vulnerability identified as CVE-2005-2450 represents a critical security flaw in Clam AntiVirus version 0.86.1 and earlier, specifically affecting the libclamav library's handling of three distinct file format processors. This issue manifests as multiple integer overflows occurring within the TNEF, CHM, and FSG file format parsers, creating a pathway for remote privilege escalation attacks. The vulnerability's impact extends beyond simple denial of service, as it enables attackers to execute arbitrary code with elevated privileges on systems running vulnerable versions of ClamAV.
The technical implementation of this vulnerability stems from improper input validation within the file format processors that handle TNEF (Transport Neutral Encapsulation Format) email attachments, CHM (Compiled HTML Help) files, and FSG compressed file formats. These processors fail to properly validate integer values during file parsing operations, leading to situations where maliciously crafted integer values can cause arithmetic overflow conditions. When such overflows occur, they can result in memory corruption that attackers can potentially exploit to manipulate program execution flow and gain unauthorized privileges.
The operational impact of this vulnerability is significant within email security environments where ClamAV serves as a primary antivirus scanning solution. Attackers can craft specially formatted email messages containing malicious attachments that trigger the integer overflow conditions when ClamAV attempts to scan these files. This creates a remote code execution vector that allows adversaries to bypass normal security boundaries and potentially gain system-level access. The vulnerability affects systems where ClamAV is deployed as a mail scanner or content filter, making it particularly dangerous in enterprise email environments and network security appliances.
From a cybersecurity perspective, this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how buffer overflows and integer overflows can lead to privilege escalation attacks. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the use of software vulnerabilities to gain elevated system privileges. The exploitation process typically involves crafting malicious files that trigger the integer overflow in the vulnerable parsing logic, followed by memory corruption that allows execution of attacker-controlled code. Organizations should implement immediate mitigations including patching to versions 0.86.2 and later, which contain fixes for these integer overflow conditions, and consider network segmentation to limit exposure of vulnerable systems. Additionally, implementing email filtering rules that block suspicious TNEF, CHM, and FSG attachments can provide additional defense in depth while patches are deployed.