CVE-2021-27185
📋 TL;DR
CVE-2021-27185 is a command injection vulnerability in the samba-client Node.js package that allows attackers to execute arbitrary commands on the host system. This affects any application using vulnerable versions of the samba-client package. The vulnerability exists because the package uses the insecure process.exec function without proper input validation.
💻 Affected Systems
- samba-client Node.js package
📦 What is this software?
Samba Client by Samba Client Project
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with remote code execution leading to data theft, ransomware deployment, or complete system takeover.
Likely Case
Arbitrary command execution with the privileges of the Node.js process, potentially leading to lateral movement, data exfiltration, or service disruption.
If Mitigated
Limited impact if the Node.js process runs with minimal privileges and proper input validation is implemented at the application layer.
🎯 Exploit Status
The vulnerability is straightforward to exploit as it involves command injection through user input. Public proof-of-concept code exists in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.0.0
Vendor Advisory: https://github.com/eflexsystems/node-samba-client/security/advisories
Restart Required: Yes
Instructions:
1. Update package.json to require samba-client version 4.0.0 or higher. 2. Run 'npm update samba-client' or 'yarn upgrade samba-client'. 3. Restart the Node.js application. 4. Test that SMB functionality still works correctly.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation and sanitization for all user inputs passed to samba-client functions.
Process Sandboxing
linuxRun Node.js application with minimal privileges and in a containerized or sandboxed environment.
docker run --cap-drop=ALL --security-opt=no-new-privileges node-app
🧯 If You Can't Patch
- Remove or disable the samba-client functionality if not essential
- Implement network segmentation to isolate systems using vulnerable versions
🔍 How to Verify
Check if Vulnerable:
Check package.json or run 'npm list samba-client' to see if version is below 4.0.0Check Version:
npm list samba-client | grep samba-clientVerify Fix Applied:
Run 'npm list samba-client' and verify version is 4.0.0 or higher, then test SMB functionality📡 Detection & Monitoring
Log Indicators:
- Unusual process executions from Node.js
- Suspicious command-line arguments in process logs
- Failed SMB authentication attempts followed by command execution
Network Indicators:
- Unexpected outbound connections from Node.js processes
- SMB protocol anomalies
SIEM Query:
process.name:node AND cmdline:*samba* AND (cmdline:*;* OR cmdline:*|* OR cmdline:*`*)🔗 References
- https://advisory.checkmarx.net/advisory/CX-2021-4302
- https://github.com/eflexsystems/node-samba-client/commit/5bc3bbad9b8d02243bc861a11ec73f788fbb1235
- https://github.com/eflexsystems/node-samba-client/releases/tag/4.0.0
- https://security.netapp.com/advisory/ntap-20210319-0002/
- https://www.npmjs.com/package/samba-client
- https://advisory.checkmarx.net/advisory/CX-2021-4302
- https://github.com/eflexsystems/node-samba-client/commit/5bc3bbad9b8d02243bc861a11ec73f788fbb1235
- https://github.com/eflexsystems/node-samba-client/releases/tag/4.0.0
- https://security.netapp.com/advisory/ntap-20210319-0002/
- https://www.npmjs.com/package/samba-client
