CVE-2005-3226 in ArcaVir Antivirus
Summary
by MITRE
Multiple interpretation error in unspecified versions of ArcaVir Antivirus allows remote attackers to bypass virus detection via a malicious executable in a specially crafted RAR file with malformed central and local headers, which can still be opened by products such as Winrar and PowerZip, even though they are rejected as corrupted by Winzip and BitZipper.
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Analysis
by VulDB Data Team • 07/27/2017
The vulnerability described in CVE-2005-3226 represents a critical flaw in ArcaVir Antivirus software that demonstrates a fundamental weakness in archive file handling and malware detection mechanisms. This issue stems from how the antivirus software interprets and processes RAR archive files, specifically targeting the central and local headers that define the structure and contents of compressed archives. The vulnerability exploits a discrepancy in how different archive utilities handle malformed file structures, creating a dangerous gap in security coverage.
The technical implementation of this vulnerability involves a sophisticated manipulation of RAR file format headers that allows malicious code to evade detection while maintaining compatibility with legitimate archive utilities. When a specially crafted RAR file is processed, the malformed central and local headers cause ArcaVir to misinterpret the file structure, leading to incorrect virus detection decisions. This error in interpretation occurs because the antivirus engine fails to properly validate the archive metadata against established file format specifications, creating a scenario where the software accepts files that should be rejected based on their corrupted structure.
The operational impact of this vulnerability extends beyond simple detection failure, as it demonstrates a broader class of problems in antivirus software architecture that can be exploited by attackers to deliver malicious payloads undetected. The fact that these malformed files can still be opened by popular utilities like Winrar and PowerZip while being rejected by Winzip and BitZipper indicates that the vulnerability is not merely a parsing issue but represents a fundamental flaw in how the antivirus software handles edge cases in file format interpretation. This creates a dangerous scenario where legitimate archive utilities can open malicious files while security software fails to detect the threat, effectively creating a false sense of security for users.
From a cybersecurity perspective, this vulnerability aligns with CWE-1108, which addresses issues in the interpretation of file format structures, and represents a clear example of how incomplete validation can lead to security bypasses. The attack vector described in this vulnerability follows patterns consistent with ATT&CK technique T1070.006 for "Indicator Removal on Host: File Deletion", as the malicious code can bypass detection mechanisms that should identify and neutralize threats within archive files. The vulnerability also demonstrates characteristics of T1566.001 for "Phishing: Spearphishing Attachment", where attackers can craft malicious files that appear legitimate to archive utilities but contain hidden threats.
The mitigation strategies for this vulnerability require comprehensive updates to the antivirus software's archive handling routines, including enhanced validation of file headers and improved error handling mechanisms. Organizations should implement layered security approaches that include multiple antivirus solutions, regular software updates, and network-based detection systems that can identify suspicious archive file behaviors regardless of endpoint protection status. Additionally, system administrators should consider implementing strict file type controls and network segmentation to limit the potential impact of such vulnerabilities, while also ensuring that all archive utilities are kept current with security patches that address similar header interpretation flaws.