CVE-2005-3211 in BitDefender Antivirus
Summary
by MITRE
Multiple interpretation error in unspecified versions of BitDefender 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 • 07/26/2017
The vulnerability described in CVE-2005-3211 represents a critical weakness in BitDefender Antivirus software that stems from improper handling of archive file structures during virus scanning operations. This flaw specifically affects the interpretation of RAR file formats where malicious executables are embedded within specially crafted archive files containing malformed central and local headers. The issue demonstrates a fundamental mismatch between how different archive utilities process and validate file structures, creating a security gap that attackers can exploit to evade detection mechanisms.
The technical implementation of this vulnerability involves the manipulation of RAR file header structures to create files that appear valid to popular archive utilities like WinRAR and PowerZip while simultaneously being flagged as corrupted by other tools such as WinZip and BitZipper. This discrepancy arises from different validation algorithms and interpretation methods employed by various software vendors. The malformed headers cause BitDefender's antivirus engine to misinterpret the archive contents, allowing malicious code to bypass detection by treating the embedded executable as an invalid or corrupted file rather than as a potential threat.
From an operational perspective, this vulnerability creates a significant risk for organizations relying on BitDefender for malware protection, as attackers can craft RAR files that successfully execute on target systems while remaining undetected by the antivirus solution. The attack vector leverages the inconsistent behavior of archive utilities, making it particularly challenging to defend against since legitimate archive operations remain functional while malicious content slips through security controls. This type of vulnerability directly impacts the core function of antivirus software by undermining the integrity of file validation processes.
The security implications extend beyond simple detection bypass to encompass potential exploitation of other system vulnerabilities through the execution of malicious payloads. Attackers can utilize this weakness to deliver malware that would otherwise be blocked by proper antivirus functionality, potentially leading to system compromise, data exfiltration, or lateral movement within networks. This vulnerability demonstrates the importance of consistent security validation across different software implementations and highlights the risks associated with relying on single-point detection mechanisms.
Organizations should implement multiple layers of security controls to mitigate the impact of such vulnerabilities, including network-based intrusion detection systems, behavioral analysis tools, and regular updates to antivirus signatures and software versions. The flaw also underscores the need for comprehensive testing of security solutions against various file format variations and the importance of maintaining awareness of vendor-specific implementation differences that could create security gaps.
This vulnerability aligns with CWE-119, which addresses weaknesses in memory handling that can lead to buffer overflows and improper handling of data structures. The issue also relates to ATT&CK technique T1059, which covers execution through command and scripting interpreters, as malicious code embedded in archives can execute through legitimate system processes. Organizations should consider implementing additional validation mechanisms beyond traditional antivirus solutions and ensure regular security assessments to identify similar implementation gaps across their software portfolio.