CVE-2007-6279 in libFLAC
Summary
by MITRE
Multiple double free vulnerabilities in Free Lossless Audio Codec (FLAC) libFLAC before 1.2.1 allow user-assisted remote attackers to execute arbitrary code via malformed (1) Seektable values or (2) Seektable Data Offsets in a .FLAC file.
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Analysis
by VulDB Data Team • 01/12/2025
The CVE-2007-6279 vulnerability represents a critical security flaw in the Free Lossless Audio Codec library implementation that affected versions prior to 1.2.1. This vulnerability stems from multiple double free errors within the libFLAC library, which is widely used for encoding and decoding audio files in the flac format. The flaw manifests when processing malformed seektable values or seektable data offsets within .flac files, creating a scenario where memory management functions are called twice on the same memory block. These double free conditions occur during the parsing of audio metadata structures that define how audio data can be randomly accessed within the file. The vulnerability specifically targets the library's handling of seektable information, which serves as a navigation structure for locating specific portions of audio data within the file. When an attacker crafts a malicious .flac file containing malformed seektable entries, the library's memory allocation routines become compromised, leading to potential memory corruption that can be exploited by remote attackers.
The technical exploitation of this vulnerability leverages fundamental memory management flaws that align with common software security weaknesses classified under CWE-415. The double free condition occurs when the library's parser encounters invalid seektable data and attempts to free memory that has already been freed, or when it processes data that causes the same memory block to be freed multiple times during the parsing sequence. This creates a predictable memory state that can be manipulated to overwrite critical memory locations or redirect execution flow. The attack vector is user-assisted remote exploitation, meaning that an attacker must convince a victim to process a specially crafted .flac file, typically through email attachments, web downloads, or file sharing systems. The vulnerability's impact extends beyond simple code execution to potentially allow for privilege escalation or system compromise, particularly when the affected library is used in applications running with elevated privileges. The flaw demonstrates how seemingly benign audio file parsing can become a critical security risk when memory management errors are present.
The operational impact of CVE-2007-6279 affects a broad range of systems and applications that utilize the libFLAC library for audio processing. This includes media players, audio editing software, streaming services, and content management systems that handle .flac audio files. The vulnerability's remote exploitation capability means that attackers can potentially compromise systems without requiring physical access or local user interaction beyond opening the malicious file. Applications that automatically process or validate .flac files, such as content delivery networks or automated audio processing pipelines, face significant risk exposure. The vulnerability also affects systems where libFLAC is embedded within larger software packages, making the attack surface broader than initially apparent. Security teams must consider this vulnerability in their threat modeling for any system that processes audio files, particularly those that may encounter untrusted input from external sources. The exploitation of this vulnerability can result in complete system compromise, data loss, or denial of service conditions that can persist until the underlying library is updated or patched.
The recommended mitigation strategy for CVE-2007-6279 involves immediate upgrading of the libFLAC library to version 1.2.1 or later, where the double free vulnerabilities have been addressed through proper memory management implementation. System administrators should prioritize patching all affected systems, particularly those that process untrusted audio files or serve as content delivery points for audio content. Organizations should implement network segmentation and content filtering to prevent unauthorized .flac files from reaching systems that process audio content. The patch implementation should include thorough regression testing to ensure that audio processing functionality remains intact while eliminating the memory corruption vulnerabilities. Additionally, security monitoring should be enhanced to detect any attempts to exploit this vulnerability through suspicious file processing patterns. The remediation process should also consider updating all applications that depend on libFLAC to ensure complete protection, as some applications may not directly use the library but may be vulnerable through indirect dependencies. Organizations should also conduct vulnerability assessments to identify all systems that may be exposed to this attack vector through their audio processing workflows or content handling procedures.