CVE-2022-34033
📋 TL;DR
CVE-2022-34033 is a heap buffer overflow vulnerability in HTMLDoc's write_header function that allows attackers to execute arbitrary code or cause denial of service. This affects systems running HTMLDoc v1.9.15 and earlier versions that process untrusted HTML input. The vulnerability is triggered when parsing specially crafted HTML documents.
💻 Affected Systems
- HTMLDoc
📦 What is this software?
Htmldoc by Htmldoc Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the HTMLDoc process, potentially leading to full system compromise.
Likely Case
Application crash (denial of service) when processing malicious HTML files.
If Mitigated
Limited impact if HTMLDoc runs with minimal privileges and processes only trusted input.
🎯 Exploit Status
Exploitation requires crafting a malicious HTML file that triggers the heap overflow in the write_header function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.9.16 and later
Vendor Advisory: https://github.com/michaelrsweet/htmldoc/security/advisories
Restart Required: No
Instructions:
1. Download HTMLDoc v1.9.16 or later from https://github.com/michaelrsweet/htmldoc/releases
2. Compile and install according to platform instructions
3. Replace existing HTMLDoc binary with patched version
🔧 Temporary Workarounds
Disable HTML processing
allConfigure systems to avoid using HTMLDoc for processing untrusted HTML files
Run with reduced privileges
linuxExecute HTMLDoc with minimal user privileges to limit potential damage
sudo -u nobody htmldoc [options]
🧯 If You Can't Patch
- Implement strict input validation for HTML files processed by HTMLDoc
- Isolate HTMLDoc execution in container or sandbox environment
🔍 How to Verify
Check if Vulnerable:
Check HTMLDoc version: htmldoc --versionCheck Version:
htmldoc --versionVerify Fix Applied:
Verify version is v1.9.16 or later: htmldoc --version | grep -E '1\.9\.1[6-9]|1\.9\.[2-9]|1\.[1-9][0-9]'📡 Detection & Monitoring
Log Indicators:
- Segmentation fault or crash logs from HTMLDoc process
- Unexpected termination of HTMLDoc
Network Indicators:
- Unusual file uploads to systems using HTMLDoc
SIEM Query:
process_name:"htmldoc" AND (event_type:"crash" OR exit_code:139)🔗 References
- https://github.com/michaelrsweet/htmldoc/commit/a0014be47d614220db111b360fb6170ef6f3937e
- https://github.com/michaelrsweet/htmldoc/commit/ee778252faebb721afba5a081dd6ad7eaf20eef3
- https://github.com/michaelrsweet/htmldoc/issues/425
- https://github.com/michaelrsweet/htmldoc/commit/a0014be47d614220db111b360fb6170ef6f3937e
- https://github.com/michaelrsweet/htmldoc/commit/ee778252faebb721afba5a081dd6ad7eaf20eef3
- https://github.com/michaelrsweet/htmldoc/issues/425
