CVE-2021-32288
📋 TL;DR
This vulnerability is a heap buffer overflow in the HEIF library's HEVC decoder configuration record parser. Attackers can exploit this to execute arbitrary code by providing a specially crafted HEIF/HEIC image file. Any application using the vulnerable heif library (v3.6.2 and earlier) to process HEIF/HEIC images is affected.
💻 Affected Systems
- heif library
- Applications using heif library for HEIF/HEIC image processing
📦 What is this software?
Heif by Nokia
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the application processing the malicious image, potentially leading to full system compromise.
Likely Case
Application crash (denial of service) when processing malformed HEIF/HEIC files; remote code execution is possible but requires specific exploitation.
If Mitigated
If the application runs with minimal privileges (sandboxed) or has memory protection mechanisms (ASLR, DEP), impact may be limited to crash or contained code execution.
🎯 Exploit Status
Proof-of-concept available in GitHub issue; exploitation requires crafting a malicious HEIF file, but no authentication is needed if the application processes external images.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: heif library version after v3.6.2 (check latest release)
Vendor Advisory: https://github.com/nokiatech/heif/issues/87
Restart Required: Yes
Instructions:
1. Update the heif library to the latest version from the official repository. 2. Recompile or update any applications using the library. 3. Restart affected services or applications.
🔧 Temporary Workarounds
Disable HEIF/HEIC processing
allTemporarily disable support for HEIF/HEIC image formats in applications until patched.
Configure application settings to reject HEIF/HEIC files or use file type filtering.
🧯 If You Can't Patch
- Restrict application privileges to minimal levels (e.g., run as non-root user, in containers).
- Implement network filtering to block HEIF/HEIC files from untrusted sources.
🔍 How to Verify
Check if Vulnerable:
Check the heif library version; if it's v3.6.2 or earlier, it's vulnerable. Use: ldd on binaries to see linked library version.Check Version:
For Linux: dpkg -l | grep heif or rpm -qa | grep heif; or check library file version directly.Verify Fix Applied:
Verify the heif library version is updated beyond v3.6.2 and test with known malicious HEIF samples.📡 Detection & Monitoring
Log Indicators:
- Application crashes or segmentation faults when processing image files
- Error logs mentioning heif or HEVC decoder failures
Network Indicators:
- Inbound transfers of HEIF/HEIC files from untrusted sources
- Unusual outbound connections after image processing
SIEM Query:
Example: source="application_logs" AND (error="segmentation fault" OR error="buffer overflow") AND process="*heif*"