CVE-2020-26301
📋 TL;DR
CVE-2020-26301 is a command injection vulnerability in the ssh2 npm package that allows remote code execution on Windows systems. Attackers can execute arbitrary commands if untrusted input reaches the vulnerable method. Only applications using ssh2 client/server modules on Windows are affected.
💻 Affected Systems
- ssh2 npm package
📦 What is this software?
Ssh2 by Ssh2 Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Limited command execution within the context of the vulnerable application, potentially leading to data exposure or further exploitation.
If Mitigated
No impact if proper input validation is implemented or if the system is not Windows-based.
🎯 Exploit Status
Exploitation requires attacker-controlled input to reach the vulnerable method. Public proof-of-concept exists in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.4.0 and later
Vendor Advisory: https://securitylab.github.com/advisories/GHSL-2020-123-mscdex-ssh2/
Restart Required: Yes
Instructions:
1. Update ssh2 package to version 1.4.0 or later using 'npm update ssh2'. 2. Restart any applications using ssh2. 3. Verify the update with 'npm list ssh2'.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation and sanitization for any user input passed to ssh2 methods.
Platform Migration
windowsMove affected applications to Linux or macOS where this vulnerability does not exist.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Windows systems using vulnerable ssh2 versions.
- Deploy application-level firewalls or WAF rules to detect and block command injection attempts.
🔍 How to Verify
Check if Vulnerable:
Check package.json or run 'npm list ssh2' to see if version is below 1.4.0 on Windows systems.Check Version:
npm list ssh2 | grep ssh2Verify Fix Applied:
Confirm ssh2 version is 1.4.0 or higher with 'npm list ssh2' and verify no command injection occurs in testing.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in application logs
- Error messages related to ssh2 command processing
Network Indicators:
- Suspicious SSH connections with unusual payloads
- Unexpected outbound connections from ssh2 applications
SIEM Query:
source="application_logs" AND "ssh2" AND ("command injection" OR "unexpected execution")🔗 References
- https://github.com/mscdex/ssh2/commit/f763271f41320e71d5cbee02ea5bc6a2ded3ca21
- https://securitylab.github.com/advisories/GHSL-2020-123-mscdex-ssh2/
- https://www.npmjs.com/package/ssh2
- https://github.com/mscdex/ssh2/commit/f763271f41320e71d5cbee02ea5bc6a2ded3ca21
- https://securitylab.github.com/advisories/GHSL-2020-123-mscdex-ssh2/
- https://www.npmjs.com/package/ssh2
