CVE-2007-6277 in libFLAC
Summary
by MITRE
Multiple buffer overflows in Free Lossless Audio Codec (FLAC) libFLAC before 1.2.1 allow user-assisted remote attackers to execute arbitrary code via large (1) Metadata Block Size, (2) VORBIS Comment String Size, (3) Picture Metadata MIME-TYPE Size, (4) Picture Description Size, (5) Picture Data Length, (6) Padding Length, and (7) PICTURE Metadata width and height values in a .FLAC file, which result in a heap-based overflow; and large (8) VORBIS Comment String Size Length, (9) Picture MIME-Type, (10) Picture MIME-Type URL, and (11) Picture Description Length values in a .FLAC file, which result in a stack-based overflow. NOTE: some of these issues may overlap CVE-2007-4619.
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Analysis
by VulDB Data Team • 01/12/2025
The CVE-2007-6277 vulnerability represents a critical security flaw in the Free Lossless Audio Codec (FLAC) implementation within libFLAC versions prior to 1.2.1. This vulnerability manifests as multiple buffer overflow conditions that can be exploited by remote attackers through specially crafted .FLAC audio files. The flaw specifically targets the parsing logic of various metadata fields within FLAC containers, creating opportunities for arbitrary code execution when legitimate applications process these malformed files. The vulnerability affects the core audio processing libraries used by numerous media applications and operating systems, making it particularly dangerous in widespread deployment scenarios.
The technical implementation of this vulnerability stems from inadequate input validation and bounds checking within the FLAC decoder's metadata parsing routines. Attackers can construct malicious .FLAC files with oversized metadata block sizes, vorbis comment string sizes, picture metadata mime-type sizes, picture description sizes, picture data lengths, padding lengths, and picture width/height values that exceed the allocated buffer space. These oversized values cause heap-based buffer overflows when the decoder attempts to allocate memory for these metadata elements. Additionally, the vulnerability includes stack-based overflow conditions triggered by large vorbis comment string size lengths, picture mime-type values, picture mime-type urls, and picture description length values. The exploitation occurs during the parsing phase when the decoder fails to properly validate the size parameters before attempting memory allocation or data copying operations.
The operational impact of CVE-2007-6277 extends far beyond simple denial of service scenarios, as the buffer overflows can be leveraged to execute arbitrary code with the privileges of the affected application. This makes the vulnerability particularly dangerous in environments where users might encounter untrusted .FLAC files through email attachments, web downloads, or media sharing platforms. The heap-based overflow conditions can be used to corrupt heap metadata structures, potentially leading to code execution through controlled memory corruption, while stack-based overflows provide more direct pathways for stack smashing attacks. These vulnerabilities align with CWE-121 and CWE-122 categories related to stack and heap buffer overflows, respectively, and map to ATT&CK techniques such as T1059 for command and scripting interpreter execution and T1203 for exploitation for privilege escalation.
Mitigation strategies for CVE-2007-6277 require immediate patching of affected libFLAC implementations to version 1.2.1 or later, where proper bounds checking and input validation have been implemented. System administrators should also implement content filtering measures to prevent processing of untrusted .FLAC files, particularly in environments where users might encounter potentially malicious media content. Network security controls including intrusion detection systems should be configured to monitor for unusual patterns in audio file processing that might indicate exploitation attempts. Additionally, application developers should ensure their software includes proper input validation and error handling for all metadata parsing operations, implementing defensive programming practices such as using safe string handling functions and implementing comprehensive bounds checking for all buffer operations. The vulnerability demonstrates the critical importance of proper memory management in multimedia processing libraries and highlights the need for thorough security testing of audio codec implementations against malformed input data.