CVE-2013-7014 in FFmpeg
Summary
by MITRE
Integer signedness error in the add_bytes_l2_c function in libavcodec/pngdsp.c in FFmpeg before 2.1 allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via crafted PNG data.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/11/2022
The vulnerability identified as CVE-2013-7014 represents a critical integer signedness error within the FFmpeg multimedia framework's PNG decoding component. This flaw exists in the add_bytes_l2_c function located in libavcodec/pngdsp.c and affects FFmpeg versions prior to 2.1. The vulnerability stems from improper handling of signed and unsigned integer operations during PNG data processing, creating a condition where maliciously crafted PNG files can trigger unexpected behavior in the decoding pipeline. The issue manifests when the software processes PNG images containing specially constructed data that causes integer overflow or underflow conditions, leading to memory access violations that can compromise system stability.
The technical implementation of this vulnerability involves a specific code path where the add_bytes_l2_c function performs arithmetic operations on integer values without proper bounds checking or sign handling. When processing PNG data, the function encounters input values that, when treated as signed integers, produce unexpected results when compared against array boundaries or buffer sizes. This particular flaw aligns with CWE-191, which describes integer underflow (wrap under) conditions, and CWE-190, which covers integer overflow conditions. The vulnerability operates at the intersection of multimedia processing and memory safety, where the PNG decoder's assumption about input data integrity leads to memory corruption scenarios.
From an operational perspective, this vulnerability presents significant risks to systems that process untrusted PNG content, including web servers, media processing applications, and content delivery networks. Remote attackers can exploit this issue by crafting malicious PNG files that, when processed by vulnerable FFmpeg installations, trigger out-of-bounds array access conditions. The impact ranges from denial of service through application crashes to potentially more severe consequences including arbitrary code execution in certain scenarios. The vulnerability's exploitation requires minimal user interaction as it can be triggered automatically when PNG files are processed, making it particularly dangerous in automated environments. According to ATT&CK framework, this represents a privilege escalation vector through software exploitation, specifically categorized under T1203 and T1068.
Mitigation strategies for CVE-2013-7014 primarily involve immediate patching of FFmpeg installations to versions 2.1 or later where the integer signedness error has been corrected. System administrators should implement comprehensive software update policies to ensure all multimedia processing components remain current with security patches. Additional protective measures include implementing strict input validation for PNG files in web applications, deploying sandboxing mechanisms for image processing, and configuring network firewalls to restrict access to vulnerable services. Organizations should also consider implementing automated monitoring for unusual system behavior that might indicate exploitation attempts, as well as conducting regular vulnerability assessments targeting multimedia processing frameworks. The fix typically involves correcting the integer type handling in the affected function to ensure proper signedness conversion and adding bounds checking to prevent array access violations.