CVE-2021-28233
📋 TL;DR
CVE-2021-28233 is a heap-based buffer overflow vulnerability in the ok-file-formats library's JPEG parsing functionality. Attackers can exploit this by providing specially crafted JPEG files, potentially leading to arbitrary code execution. Any application using the vulnerable ok-file-formats library to process JPEG images is affected.
💻 Affected Systems
- ok-file-formats library
📦 What is this software?
Ok File Formats by Ok File Formats Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the application processing the JPEG file, potentially leading to complete system compromise.
Likely Case
Application crash (denial of service) or limited memory corruption leading to unstable behavior.
If Mitigated
Application crash with no further impact if memory protections (ASLR, DEP) are effective.
🎯 Exploit Status
Proof-of-concept exploit code is available in the GitHub issue. Exploitation requires the target to process a malicious JPEG file.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit 8b5e0f9 and later versions
Vendor Advisory: https://github.com/brackeen/ok-file-formats/issues/11
Restart Required: Yes
Instructions:
1. Update ok-file-formats library to latest version. 2. Recompile any applications using the library. 3. Restart affected services.
🔧 Temporary Workarounds
Disable JPEG processing
allConfigure applications to disable JPEG file processing if not required.
Input validation
allImplement strict validation of JPEG files before processing (size limits, magic bytes).
🧯 If You Can't Patch
- Implement network segmentation to isolate systems using vulnerable library
- Deploy application allowlisting to prevent execution of unknown binaries
🔍 How to Verify
Check if Vulnerable:
Check if application links against ok-file-formats library version 1.0.0 or earlier.Check Version:
Check library version in source code or build configuration.Verify Fix Applied:
Verify library version is updated beyond commit 8b5e0f9 and applications are recompiled.📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing JPEG files
- Memory access violation errors
Network Indicators:
- Unusual JPEG file uploads to web applications
SIEM Query:
source="application.log" AND ("segmentation fault" OR "access violation") AND "jpg" OR "jpeg"