CVE-2012-0849 in FFmpeg
Summary
by MITRE
Integer overflow in the ff_j2k_dwt_init function in libavcodec/j2k_dwt.c in FFmpeg before 0.9.1 allows remote attackers to cause a denial of service (segmentation fault and application crash) via a crafted JPEG2000 image that triggers an incorrect check for a negative value.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/12/2021
The vulnerability identified as CVE-2012-0849 represents a critical integer overflow flaw within the FFmpeg multimedia framework that affects versions prior to 0.9.1. This vulnerability resides in the ff_j2k_dwt_init function located in the libavcodec/j2k_dwt.c source file, which handles the initialization of discrete wavelet transform operations for JPEG2000 image processing. The flaw occurs when processing specially crafted JPEG2000 image files that contain malformed data structures, specifically in how the function evaluates negative value checks during the wavelet transform initialization phase. This vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which is classified as a fundamental weakness in software that can lead to various security implications.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious JPEG2000 image file containing oversized or malformed header values that cause integer overflow during the wavelet transform initialization process. When FFmpeg attempts to process this crafted image, the ff_j2k_dwt_init function performs calculations that exceed the maximum representable value for the integer data type, resulting in wraparound behavior. The specific issue arises from an incorrect validation mechanism that fails to properly check for negative values after the arithmetic operations, allowing the program to continue execution with corrupted data. This improper handling of integer arithmetic directly leads to memory corruption conditions that manifest as segmentation faults and subsequent application crashes.
The operational impact of CVE-2012-0849 extends beyond simple denial of service, as it represents a potential vector for more sophisticated attacks within multimedia processing environments. Remote attackers can leverage this vulnerability to disrupt services that depend on FFmpeg for image processing, including web servers, media streaming platforms, and content management systems that accept user-uploaded JPEG2000 files. The vulnerability affects systems where FFmpeg is integrated as a backend processing component, making it particularly dangerous in web applications where users can upload multimedia content. This flaw aligns with ATT&CK technique T1203 by enabling adversaries to cause system instability and potentially disrupt legitimate service operations. The vulnerability's impact is amplified in environments where automated processing of user content occurs without proper input validation, creating a pathway for persistent service disruption attacks.
Mitigation strategies for CVE-2012-0849 primarily focus on immediate software updates and implementation of input validation measures. The most effective solution involves upgrading to FFmpeg version 0.9.1 or later, where the integer overflow issue has been addressed through proper boundary checking and arithmetic validation. Organizations should also implement robust input sanitization procedures that validate image dimensions and header values before processing, particularly for JPEG2000 format files. Network-based mitigations can include implementing content filtering rules that restrict or scan JPEG2000 file uploads, while application-level protections should incorporate proper error handling and memory management practices. Security teams should monitor for exploitation attempts through intrusion detection systems that can identify unusual file processing patterns or memory access violations that may indicate attempted exploitation of this vulnerability. The fix implemented in the patched version demonstrates proper integer overflow protection mechanisms that prevent the wraparound conditions leading to the segmentation fault.