CVE-2005-3225 in Etrust Antivirus
Summary
by MITRE
Multiple interpretation error in unspecified versions of (1) eTrust-Iris and (2) eTrust-Vet 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 • 07/28/2017
The vulnerability described in CVE-2005-3225 represents a critical weakness in antivirus software validation mechanisms that specifically affects eTrust-Iris and eTrust-Vet antivirus products. This issue stems from multiple interpretation errors within the antivirus engines that process compressed file formats, particularly RAR archives. The flaw manifests when these products encounter specially crafted RAR files containing malicious executables with malformed central and local headers. The vulnerability exploits inconsistencies in how different compression tools handle file validation, creating a scenario where legitimate archive viewers like Winrar and PowerZip can successfully open the malformed files while competing products such as Winzip and BitZipper reject them as corrupted. This discrepancy in validation behavior creates a significant security gap that attackers can leverage to bypass antivirus detection.
The technical root cause of this vulnerability lies in the inconsistent interpretation of RAR file format specifications, specifically in how the antivirus software processes and validates the central directory and local file headers. According to CWE-119, this represents a weakness in memory handling where the software fails to properly validate input data structures, leading to potential security bypasses. The vulnerability demonstrates a classic case of format confusion where different tools interpret the same malformed data differently, with some tools being more permissive than others. The malformed headers in the RAR files create a situation where the antivirus engine's parsing logic fails to correctly identify the malicious content, as it relies on the same validation patterns that are accepted by legitimate archive viewers but rejected by other tools. This inconsistency creates a window of opportunity for attackers to craft payloads that evade detection while remaining functional in standard archive operations.
The operational impact of this vulnerability is substantial as it allows remote attackers to execute malicious code without detection by bypassing the core antivirus protection mechanisms. The attack vector requires the victim to open a specially crafted RAR file, which can be delivered through various means including email attachments, malicious websites, or compromised software distributions. The vulnerability affects both eTrust-Iris and eTrust-Vet products, which were widely deployed in enterprise environments, potentially exposing numerous organizations to persistent threats. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1204.002 for user execution, as it enables attackers to execute malicious code through legitimate archive operations. The bypass capability means that traditional signature-based detection methods become ineffective, as the malicious payload remains undetected by the antivirus engines despite being present in the system.
Organizations affected by this vulnerability should immediately implement multiple layers of protection beyond traditional antivirus solutions. The recommended mitigations include updating to patched versions of eTrust-Iris and eTrust-Vet products, implementing network-based intrusion detection systems, and deploying behavioral analysis tools that can detect anomalous file execution patterns. Security teams should also establish strict policies for handling compressed files, particularly those from untrusted sources, and implement sandboxing techniques to analyze suspicious archives before allowing them to execute on production systems. Additionally, network administrators should monitor for unusual file access patterns and implement endpoint detection and response solutions that can identify when malicious code attempts to execute within the system. The vulnerability underscores the importance of maintaining updated security software and the necessity of employing defense-in-depth strategies that do not rely solely on signature-based detection methods. Organizations should also consider implementing application whitelisting policies to prevent unauthorized executable files from running, regardless of antivirus protection status.