CVE-2018-1000620
📋 TL;DR
CVE-2018-1000620 is an insufficient entropy vulnerability in cryptiles' randomDigits() method that makes generated random numbers predictable. This affects applications using cryptiles for cryptographic operations like token generation, allowing attackers to brute-force values that should be random. All applications using cryptiles version 4.1.1 or earlier are vulnerable.
💻 Affected Systems
- cryptiles
- hapijs ecosystem applications
📦 What is this software?
Cryptiles by Cryptiles Project
Cryptiles by Cryptiles Project
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of cryptographic security leading to session hijacking, authentication bypass, or data decryption
Likely Case
Predictable token generation enabling brute-force attacks against authentication mechanisms
If Mitigated
Limited impact if proper rate limiting and monitoring are in place
🎯 Exploit Status
Exploitation depends on how the calling application uses randomDigits() - predictable output enables brute-force attacks
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.1.2
Vendor Advisory: https://github.com/hapijs/cryptiles/issues/34
Restart Required: Yes
Instructions:
1. Update cryptiles dependency to version 4.1.2 or later
2. Run 'npm update cryptiles' or update package.json
3. Restart all affected applications
4. Regenerate any cryptographic tokens created with vulnerable versions
🔧 Temporary Workarounds
Replace cryptiles with alternative
allReplace cryptiles.randomDigits() with Node.js crypto.randomBytes() or other cryptographically secure random generators
// Replace: cryptiles.randomDigits(n)
// With: require('crypto').randomBytes(n).toString('hex')
🧯 If You Can't Patch
- Implement strict rate limiting on all endpoints using cryptiles-generated tokens
- Monitor for unusual authentication patterns and brute-force attempts
🔍 How to Verify
Check if Vulnerable:
Check package.json or node_modules/cryptiles/package.json for version <4.1.2Check Version:
npm list cryptiles | grep cryptilesVerify Fix Applied:
Verify cryptiles version is 4.1.2 or higher and test randomDigits() output for sufficient entropy📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts with similar token patterns
- Unusual success rates for token-based authentication
Network Indicators:
- High volume of requests to token-validation endpoints
- Patterned token values in network traffic
SIEM Query:
source="application_logs" AND ("authentication_failure" OR "invalid_token") COUNT BY src_ip > threshold