CVE-2020-28438
📋 TL;DR
CVE-2020-28438 is a command injection vulnerability in the deferred-exec npm package that allows attackers to execute arbitrary commands on the host system. All versions of deferred-exec are affected. Any application using this vulnerable package could be compromised.
💻 Affected Systems
- deferred-exec npm package
📦 What is this software?
Deferred Exec by Deferred Exec Project
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ 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
Unauthenticated remote code execution allowing attackers to run arbitrary commands with the privileges of the application using the package.
If Mitigated
Limited impact if proper input validation and sandboxing are implemented, though the vulnerability still exists in the package.
🎯 Exploit Status
The vulnerability is in line 42 of lib/deferred-exec.js where user input is passed to exec() without proper sanitization. Exploitation requires the attacker to control input to the vulnerable function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: https://security.snyk.io/vuln/SNYK-JS-DEFERREDEXEC-1050433
Restart Required: Yes
Instructions:
1. Remove deferred-exec package from your project. 2. Find alternative packages for deferred execution functionality. 3. Update package.json to remove dependency. 4. Run npm uninstall deferred-exec. 5. Restart your application.
🔧 Temporary Workarounds
Input validation wrapper
allCreate a wrapper function that validates and sanitizes all inputs before passing to deferred-exec functions
// Implement strict input validation for all parameters passed to deferred-exec functions
// Use allowlists for acceptable inputs and reject all others
Sandbox execution
allRun the vulnerable application in a container or sandbox with minimal privileges
docker run --read-only --cap-drop=ALL -u nobody your-app
// Or use Node.js child_process with restricted permissions
🧯 If You Can't Patch
- Implement strict network controls to limit access to affected applications
- Monitor for suspicious process creation and command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check if deferred-exec is in your package.json or node_modules: grep -r 'deferred-exec' package.json && ls node_modules/ | grep deferred-execCheck Version:
npm list deferred-execVerify Fix Applied:
Verify deferred-exec is not in package.json dependencies and node_modules directory is clean of the package📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns
- Processes spawned with unexpected arguments
- Error logs showing command execution failures
Network Indicators:
- Unexpected outbound connections from Node.js processes
- Command and control traffic patterns
SIEM Query:
process.name:node AND (process.args:*cmd* OR process.args:*sh* OR process.args:*bash*) AND NOT process.args:expected-normal-command