CVE-2022-33047
📋 TL;DR
CVE-2022-33047 is a critical heap buffer overflow after free vulnerability in OTFCC v0.10.4 that allows attackers to execute arbitrary code or cause denial of service. This affects systems running OTFCC font conversion tools, particularly those processing untrusted font files. The vulnerability resides in otfccbuild.c and can be triggered during font parsing operations.
💻 Affected Systems
- OTFCC (OpenType Font Compiler/Converter)
📦 What is this software?
Otfcc by Otfcc Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with SYSTEM/root privileges leading to complete system compromise, data theft, and persistent backdoor installation.
Likely Case
Application crash (denial of service) when processing malicious font files, potentially disrupting font conversion workflows.
If Mitigated
Limited to application crash if memory protections (ASLR, DEP) are effective, but still poses significant risk.
🎯 Exploit Status
Proof of concept available in the Google Drive reference. Exploitation requires crafting a malicious font file that triggers the use-after-free condition during parsing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v0.10.5 or later
Vendor Advisory: http://otfcc.com
Restart Required: No
Instructions:
1. Visit http://otfcc.com 2. Download latest version (v0.10.5+) 3. Replace existing OTFCC installation 4. Verify version with 'otfccdump --version' or 'otfccbuild --version'
🔧 Temporary Workarounds
Restrict Font Processing
allLimit OTFCC usage to trusted font sources only and implement file validation
Sandbox Execution
linuxRun OTFCC in isolated containers or sandboxes with limited privileges
docker run --read-only --cap-drop=ALL -v /trusted-fonts:/fonts otfcc-container
🧯 If You Can't Patch
- Disable OTFCC usage entirely until patched
- Implement strict input validation and only process fonts from verified sources
🔍 How to Verify
Check if Vulnerable:
Run 'otfccdump --version' or 'otfccbuild --version' and check if output contains '0.10.4'Check Version:
otfccdump --version 2>&1 | grep -i version || otfccbuild --version 2>&1 | grep -i versionVerify Fix Applied:
Run version check command and confirm version is 0.10.5 or higher📡 Detection & Monitoring
Log Indicators:
- OTFCC process crashes with segmentation faults
- Abnormal memory usage patterns in OTFCC processes
- Multiple failed font parsing attempts
Network Indicators:
- Unusual font file downloads to systems running OTFCC
- Font file transfers to processing servers
SIEM Query:
process_name:"otfcc" AND (event_type:"crash" OR memory_usage:"spike")