CVE-2019-10769
📋 TL;DR
CVE-2019-10769 is a critical vulnerability in the safer-eval npm package that allows arbitrary code execution by triggering a RangeError. This affects any application using vulnerable versions of safer-eval to sandbox JavaScript evaluation, potentially enabling attackers to execute malicious code on the server. Developers using this package for code evaluation in Node.js applications are at risk.
💻 Affected Systems
- safer-eval npm package
📦 What is this software?
Safer Eval by Safer Eval Project
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise allowing attackers to execute arbitrary system commands, steal sensitive data, install malware, or pivot to other systems in the network.
Likely Case
Remote code execution leading to data exfiltration, cryptocurrency mining, or participation in botnets.
If Mitigated
Limited impact if the vulnerable package is not exposed to untrusted input or runs in a highly restricted environment.
🎯 Exploit Status
Exploitation requires the ability to provide input to the safer-eval function. Public proof-of-concept code demonstrates the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.3.4 and later
Vendor Advisory: https://github.com/commenthol/safer-eval/security/advisories/GHSA-v63x-xc9j-hhvq
Restart Required: Yes
Instructions:
1. Update package.json to require safer-eval version 1.3.4 or higher. 2. Run 'npm update safer-eval' or 'yarn upgrade safer-eval'. 3. Restart the application to load the patched version.
🔧 Temporary Workarounds
Remove safer-eval usage
allReplace safer-eval with alternative safe evaluation methods or remove the functionality entirely.
npm uninstall safer-eval
Input validation and sanitization
allImplement strict input validation and sanitization before passing data to safer-eval.
🧯 If You Can't Patch
- Isolate the vulnerable application in a restricted network segment with no internet access.
- Implement strict input validation and monitoring for any code execution attempts.
🔍 How to Verify
Check if Vulnerable:
Check package.json or run 'npm list safer-eval' to see the installed version. If version is below 1.3.4, the system is vulnerable.Check Version:
npm list safer-eval | grep safer-evalVerify Fix Applied:
After updating, verify the version with 'npm list safer-eval' shows 1.3.4 or higher and test that the application functions correctly without errors.📡 Detection & Monitoring
Log Indicators:
- Unexpected RangeError exceptions in application logs
- Unusual process spawns or system commands from Node.js processes
- Abnormal network connections from the application server
Network Indicators:
- Outbound connections to suspicious IPs or domains from the application server
- Unexpected data exfiltration patterns
SIEM Query:
source="application.logs" AND ("RangeError" OR "safer-eval") AND severity=HIGH