CVE-2005-3499 in F-Prot Antivirus
Summary
by MITRE
Frisk F-Prot Antivirus allows remote attackers to bypass protection via a ZIP file with a version header greater than 15, which prevents F-Prot from decompressing and analyzing the file.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability described in CVE-2005-3499 represents a critical flaw in the Frisk F-Prot Antivirus software that directly impacts its core functionality and security posture. This issue specifically affects the antivirus software's ability to properly handle compressed files, particularly those in the ZIP format, creating a significant bypass opportunity for malicious actors. The vulnerability stems from the software's overly restrictive handling of ZIP file version headers, which are part of the standard ZIP file format specification used across various operating systems and applications. When a ZIP file contains a version header value greater than 15, the F-Prot antivirus system fails to decompress and analyze the contents, effectively rendering its protection mechanisms useless against threats embedded within such files.
The technical implementation of this vulnerability lies in the antivirus software's parsing logic for ZIP archives. Standard ZIP files use version headers to indicate the minimum version required to extract the archive, with version 15 being the maximum supported by many older implementations. However, F-Prot's implementation appears to have a hard-coded limitation that prevents processing files with version headers exceeding 15, regardless of whether the actual extraction capabilities support such files. This design flaw creates an exploitable condition where attackers can craft malicious ZIP files with version headers above 15, knowing that F-Prot will simply ignore them rather than attempt proper analysis. The vulnerability is classified as a buffer over-read or improper input validation issue, as the software does not properly validate or handle version headers that exceed its expected range, potentially leading to incomplete threat detection and analysis.
From an operational impact perspective, this vulnerability creates a substantial security gap in environments relying on F-Prot for protection, particularly in scenarios where users may encounter legitimate or malicious ZIP files with higher version headers. The bypass mechanism is straightforward and does not require sophisticated techniques, making it accessible to attackers with minimal technical expertise. Organizations using F-Prot may experience false security assurances while their systems remain vulnerable to attacks that exploit this specific weakness. The vulnerability particularly impacts enterprise environments where automated file scanning is critical, as the antivirus system's inability to process certain ZIP files means that malicious payloads could remain undetected, potentially leading to data breaches, system compromise, or other security incidents.
The mitigation strategies for this vulnerability involve immediate software updates from the vendor to address the ZIP file handling logic and implement proper version header validation. System administrators should also consider implementing additional layers of security controls, including network-based file inspection systems, sandboxing mechanisms, and enhanced monitoring for suspicious file transfers. The vulnerability demonstrates the importance of proper input validation and the potential consequences of overly restrictive or poorly implemented file format parsing logic. From a compliance perspective, this issue could impact organizations subject to security standards such as iso 27001, which require robust protection mechanisms and proper vulnerability management processes. The flaw also aligns with common attack patterns identified in the mitre att&ck framework, particularly in the execution and persistence phases where attackers leverage system weaknesses to deploy malicious payloads. Organizations should also consider implementing network segmentation and file access controls to limit the potential impact of such bypasses, while maintaining regular vulnerability assessments to identify similar implementation weaknesses in other security tools and systems.