CVE-2005-3212 in NOD32 Antivirus
Summary
by MITRE
Multiple interpretation error in unspecified versions of NOD32 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-2005-3212 represents a critical flaw in the NOD32 Antivirus software that demonstrates the complexities of file format parsing and malware detection. This issue stems from an interpretation error in how the antivirus software processes RAR archive files, specifically when encountering malformed central and local headers within these archives. The vulnerability exists in unspecified versions of the NOD32 Antivirus product and creates a significant security gap that allows malicious actors to evade detection mechanisms. The flaw exploits the inconsistent handling of malformed archive structures across different decompression tools, where some applications like Winrar and PowerZip successfully process these files while others such as Winzip and BitZipper reject them as corrupted.
The technical implementation of this vulnerability involves the manipulation of RAR file headers to create a situation where the NOD32 antivirus engine misinterprets the file structure during analysis. When processing a specially crafted RAR file with malformed headers, the antivirus software fails to properly validate the archive's integrity and instead treats the malicious executable as a legitimate file. This misinterpretation occurs because the antivirus engine does not adequately implement robust header validation routines that would identify the malformed structure as potentially malicious. The vulnerability is particularly concerning because it leverages the fact that different archive utilities have varying tolerance levels for malformed headers, creating an exploitation window where the same malicious file can be processed successfully by some tools while being flagged by others.
From an operational perspective, this vulnerability creates a dangerous bypass mechanism for attackers seeking to deploy malware through RAR archives. The ability to craft files that appear legitimate to some decompression tools while evading detection by NOD32 antivirus software demonstrates a fundamental weakness in the product's threat analysis capabilities. Security professionals must understand that this flaw could allow adversaries to deliver malicious payloads through seemingly benign archive files, potentially compromising systems that rely on NOD32 for protection. The vulnerability's impact extends beyond simple detection failure, as it represents a broader class of issues related to improper file format handling and validation that can affect numerous security products. The inconsistent behavior across different archive utilities also suggests that this may be part of a larger pattern where different software vendors implement varying levels of robustness in their file parsing routines.
The security implications of this vulnerability align with several cybersecurity frameworks and threat modeling approaches. From a CWE perspective, this issue relates to CWE-129, which addresses insufficient input validation, and CWE-125, which covers out-of-bounds read conditions. The vulnerability also maps to ATT&CK technique T1059.007, which covers obfuscated files or information, as attackers can use malformed archives to obscure malicious content. Organizations using affected NOD32 versions face significant risk of undetected malware delivery, particularly in environments where RAR archives are commonly used for file distribution. The flaw demonstrates the importance of comprehensive input validation and the need for security products to maintain consistent behavior when processing potentially malicious files. Remediation efforts should include immediate software updates from ESET, the vendor of NOD32, along with network monitoring for suspicious RAR file activity and enhanced user education about the risks of opening unknown archive files. Additionally, this vulnerability highlights the importance of implementing multiple layers of security controls, as relying on a single detection mechanism may prove insufficient against sophisticated evasion techniques.