CVE-2024-7272: FFmpeg Heap Buffer Overflow Vulnerability

CVE-2024-7272 Overview

A critical heap-based buffer overflow vulnerability was discovered in FFmpeg versions up to 5.1.5. The vulnerability exists in the fill_audiodata function within the /libswresample/swresample.c file. This flaw can be exploited remotely by attackers through manipulation of audio data, potentially leading to arbitrary code execution or denial of service conditions.

Critical Impact

Remote attackers can exploit this heap-based buffer overflow to potentially execute arbitrary code or crash applications using vulnerable FFmpeg versions. The vulnerability was patched in version 6.0 but the backport for the 5.1 branch was initially forgotten.

Affected Products

• FFmpeg versions up to and including 5.1.5
• FFmpeg versions prior to 6.0 (commit 9903ba28c28ab18dc7b7b6fb8571cc8b5caae1a6)
• Applications and systems embedding vulnerable FFmpeg libswresample components

Discovery Timeline

• 2024-08-12 - CVE-2024-7272 published to NVD
• 2024-08-13 - Last updated in NVD database

Technical Details for CVE-2024-7272

Vulnerability Analysis

This vulnerability is a heap-based buffer overflow (CWE-122) that also falls under the broader category of out-of-bounds write vulnerabilities (CWE-787). The flaw resides in FFmpeg's libswresample library, specifically within the fill_audiodata function responsible for handling audio data during resampling operations.

The vulnerability allows for remote exploitation through specially crafted media files. When FFmpeg processes malicious audio data, the fill_audiodata function fails to properly validate buffer boundaries, resulting in heap memory corruption. This can lead to arbitrary code execution in the context of the application processing the media file, or cause application crashes resulting in denial of service.

Notably, while FFmpeg version 6.0 addressed this vulnerability through commit 9903ba28c28ab18dc7b7b6fb8571cc8b5caae1a6, the corresponding backport to the 5.1 branch was inadvertently omitted, leaving users on older LTS versions exposed until the release of version 5.1.6.

Root Cause

The root cause of CVE-2024-7272 is improper bounds checking in the fill_audiodata function within libswresample. When processing audio sample data during resampling operations, the function does not adequately validate the size of input data against allocated heap buffer sizes. This oversight allows carefully crafted audio data to write beyond the boundaries of the allocated heap buffer, corrupting adjacent memory structures.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no authentication or user interaction beyond processing a malicious media file. An attacker can exploit this vulnerability by:

1. Crafting a malicious audio or multimedia file containing specially formed audio data
2. Delivering the file to a victim through various channels (web downloads, email attachments, media streaming)
3. Triggering the vulnerability when the victim's FFmpeg-based application processes the file

The exploitation process targets the audio resampling functionality, where the fill_audiodata function is called during audio format conversion. Proof-of-concept exploits have been publicly disclosed, as documented in the GitHub PoC Repository.

Detection Methods for CVE-2024-7272

Indicators of Compromise

• Unexpected crashes in FFmpeg-based applications during audio processing
• Memory corruption errors or segmentation faults in libswresample operations
• Unusual process behavior in media transcoding or streaming applications
• Core dumps indicating heap corruption in FFmpeg processes

Detection Strategies

• Monitor for abnormal memory allocation patterns in FFmpeg processes during audio resampling
• Implement application crash monitoring for FFmpeg-dependent services
• Use memory sanitizers (AddressSanitizer, Valgrind) during development and testing to detect heap overflows
• Deploy intrusion detection signatures targeting malformed audio data structures

Monitoring Recommendations

• Enable detailed logging for media processing applications to track processing failures
• Implement file integrity monitoring for FFmpeg binaries and libraries
• Configure alerting for repeated application crashes in media processing pipelines
• Monitor network traffic for suspicious media file transfers targeting known vulnerable endpoints

How to Mitigate CVE-2024-7272

Immediate Actions Required

• Upgrade FFmpeg to version 5.1.6 or later if using the 5.1 branch
• Upgrade FFmpeg to version 6.0 or later with commit 9903ba28c28ab18dc7b7b6fb8571cc8b5caae1a6 applied
• Audit all applications and systems that embed or depend on FFmpeg libswresample
• Prioritize patching for internet-facing media processing services

Patch Information

The vulnerability was fixed in FFmpeg version 6.0 through commit 9903ba28c28ab18dc7b7b6fb8571cc8b5caae1a6. A backport to the 5.1 branch was released in version 5.1.6. Organizations should verify their FFmpeg installations and update to patched versions immediately.

For additional technical details, refer to the FFmpeg Official Website and the VulDB advisory.

Workarounds

• Restrict processing of untrusted media files until patching is complete
• Implement input validation and sandboxing for media processing workflows
• Run FFmpeg processes with reduced privileges to limit impact of potential exploitation
• Consider using application-level firewalls to filter potentially malicious media content

# Verify FFmpeg version to check vulnerability status
ffmpeg -version | head -n 1

# Check for specific vulnerable library
ffmpeg -version | grep libswresample

# Update FFmpeg on Debian/Ubuntu systems
sudo apt update && sudo apt install --only-upgrade ffmpeg

# Update FFmpeg on RHEL/CentOS systems
sudo yum update ffmpeg