CVE-2006-3334 in libpng
Summary
by MITRE
Buffer overflow in the png_decompress_chunk function in pngrutil.c in libpng before 1.2.12 allows context-dependent attackers to cause a denial of service and possibly execute arbitrary code via unspecified vectors related to "chunk error processing," possibly involving the "chunk_name".
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Analysis
by VulDB Data Team • 06/23/2019
The vulnerability described in CVE-2006-3334 represents a critical buffer overflow condition within the libpng library version 1.2.11 and earlier. This flaw exists in the png_decompress_chunk function located in the pngrutil.c source file, which is part of the PNG image processing library widely used across numerous applications and systems for handling portable network graphics files. The buffer overflow occurs during the processing of PNG chunks, specifically when handling error conditions within chunk data structures that define the organization and content of PNG files.
The technical nature of this vulnerability stems from improper bounds checking during the decompression of PNG chunks, where the library fails to adequately validate the size and structure of incoming data before attempting to copy it into fixed-size buffers. When maliciously crafted PNG files are processed, the chunk_name field and related error handling mechanisms can trigger memory corruption that leads to unpredictable behavior. This vulnerability is context-dependent, meaning it requires specific conditions to be exploited successfully, typically involving the processing of specially crafted PNG files that manipulate the chunk error processing routines.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous in environments where applications process untrusted image files from external sources. Attackers can leverage this flaw to cause applications using libpng to crash or, in more sophisticated attacks, to execute arbitrary code with the privileges of the affected application. This makes the vulnerability particularly concerning for web servers, image processing applications, and any system that handles PNG file uploads or downloads from untrusted users. The vulnerability affects a wide range of software that depends on libpng for image handling, including web browsers, image viewers, and content management systems.
Mitigation strategies for CVE-2006-3334 involve immediate patching of libpng installations to version 1.2.12 or later, which contains the necessary fixes for the buffer overflow conditions. System administrators should also implement input validation measures to filter or reject malformed PNG files before they reach applications that use libpng. Additionally, organizations should consider implementing network segmentation and access controls to limit the potential impact of successful exploitation attempts. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and could potentially map to ATT&CK technique T1203 for exploitation of software vulnerabilities. The fix implemented in libpng 1.2.12 includes enhanced bounds checking and proper memory management during chunk processing, addressing the root cause of the buffer overflow condition in the png_decompress_chunk function.