CVE-2021-32546
📋 TL;DR
CVE-2021-32546 is a remote code execution vulnerability in Gogs Git hosting software. Unauthenticated attackers can exploit missing input validation to overwrite Git configuration files and execute arbitrary commands on the server. All Gogs instances running vulnerable versions are affected.
💻 Affected Systems
- Gogs
📦 What is this software?
Gogs by Gogs
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise allowing attackers to execute arbitrary commands with the privileges of the Gogs process, potentially leading to data theft, lateral movement, or complete system takeover.
Likely Case
Remote code execution leading to unauthorized access, data exfiltration, or deployment of malware/backdoors on the affected Gogs server.
If Mitigated
Limited impact with proper network segmentation and least privilege configurations, potentially containing the attack to the Gogs application environment.
🎯 Exploit Status
Exploitation requires a registered user account. The vulnerability has been publicly disclosed with proof-of-concept details available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.12.8 and later
Vendor Advisory: https://github.com/gogs/gogs/security/advisories/GHSA-56j7-2pm8-rgmx
Restart Required: Yes
Instructions:
1. Backup your Gogs data and configuration. 2. Stop the Gogs service. 3. Update to Gogs version 0.12.8 or later. 4. Restart the Gogs service. 5. Verify the update was successful.
🔧 Temporary Workarounds
Disable User Registration
allPrevent new user registration to block the initial attack vector
Edit app.ini configuration file and set DISABLE_REGISTRATION = true
Restrict Repository Operations
allLimit repository creation and editing permissions to trusted users only
Configure Gogs permissions to restrict repository operations to administrators
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Gogs from critical systems
- Enable detailed logging and monitoring for suspicious repository configuration changes
🔍 How to Verify
Check if Vulnerable:
Check Gogs version by accessing the web interface or examining the installation directory. Versions below 0.12.8 are vulnerable.Check Version:
Check the Gogs web interface dashboard or examine the VERSION file in the Gogs installation directoryVerify Fix Applied:
Verify the Gogs version is 0.12.8 or higher and test that repository configuration files cannot be overwritten via the GUI.📡 Detection & Monitoring
Log Indicators:
- Unusual repository configuration changes
- Multiple failed attempts to create or rename files with special characters
- Unexpected SSH command executions
Network Indicators:
- Unusual outbound connections from Gogs server
- SSH connections to unexpected destinations
SIEM Query:
source="gogs" AND (event="repository_config_change" OR file_name="\" OR file_name=".git/config")