CVE-2021-26541
📋 TL;DR
CVE-2021-26541 is a command injection vulnerability in the gitlog npm package that allows attackers to execute arbitrary commands on the host system. This affects applications using vulnerable versions of gitlog to process git log data. The vulnerability is particularly dangerous because it can be exploited through user-controlled input.
💻 Affected Systems
- gitlog npm package
📦 What is this software?
Gitlog by Gitlog Project
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with remote code execution, allowing attackers to install malware, exfiltrate data, or pivot to other systems.
Likely Case
Arbitrary command execution in the context of the application, potentially leading to data theft, system modification, or service disruption.
If Mitigated
Limited impact if proper input validation and sandboxing are implemented, potentially only affecting the application's own data.
🎯 Exploit Status
Exploitation requires the vulnerable function to process attacker-controlled input. The fix in PR #65 demonstrates the exploit pattern.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.0.4 and later
Vendor Advisory: https://github.com/domharrington/node-gitlog/pull/65
Restart Required: Yes
Instructions:
1. Update package.json to require gitlog version 4.0.4 or higher. 2. Run 'npm update gitlog' or 'yarn upgrade gitlog'. 3. Restart the application to load the patched version.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict input validation for all parameters passed to gitlog function
Sandbox execution
linuxRun the application in a container or with limited privileges to restrict command execution impact
docker run --read-only --cap-drop=ALL -u nobody node-app
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all user inputs passed to gitlog
- Run the application with minimal privileges and in a sandboxed environment
🔍 How to Verify
Check if Vulnerable:
Check package.json or run 'npm list gitlog' to see if version is below 4.0.4Check Version:
npm list gitlog | grep gitlogVerify Fix Applied:
Verify gitlog version is 4.0.4 or higher with 'npm list gitlog' and test with known malicious inputs📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns
- Git operations with suspicious parameters
- Process spawning from Node.js with unexpected arguments
Network Indicators:
- Outbound connections from Node.js process to unexpected destinations
- Data exfiltration patterns
SIEM Query:
process.name:node AND cmdline:*git* AND (cmdline:*;* OR cmdline:*&* OR cmdline:*|*)