CVE-2018-25107
📋 TL;DR
CVE-2018-25107 is a cryptographic vulnerability in Perl's Crypt::Random::Source package where it falls back to the insecure built-in rand() function when other random sources fail. This allows attackers to predict random values used for cryptographic operations like key generation, session tokens, or nonces. Any Perl application using Crypt::Random::Source versions before 0.13 for security-sensitive operations is affected.
💻 Affected Systems
- Crypt::Random::Source Perl module
⚠️ 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
Complete compromise of cryptographic security leading to predictable encryption keys, session hijacking, authentication bypass, and data decryption.
Likely Case
Weakened cryptographic operations allowing attackers to predict or brute-force security tokens, session IDs, or cryptographic nonces.
If Mitigated
Limited impact if application uses additional security controls, but cryptographic operations remain fundamentally weakened.
🎯 Exploit Status
Exploitation requires the attacker to trigger the fallback condition or predict when it occurs, but the vulnerability itself is straightforward to exploit once identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.13
Vendor Advisory: https://metacpan.org/release/ETHER/Crypt-Random-Source-0.13/changes
Restart Required: No
Instructions:
1. Update Crypt::Random::Source using CPAN: 'cpan Crypt::Random::Source'
2. Verify installation of version 0.13 or later
3. Restart any Perl applications using the module
🔧 Temporary Workarounds
Use alternative random source
allConfigure Crypt::Random::Source to use secure random sources and avoid fallback to rand()
perl -MCrypt::Random::Source=strong -e 'print Crypt::Random::Source->get(32)'
🧯 If You Can't Patch
- Replace Crypt::Random::Source with alternative secure random modules like Crypt::URandom or Crypt::Random::Secure
- Implement application-level validation of random values and use additional entropy sources
🔍 How to Verify
Check if Vulnerable:
Check installed version: 'perl -MCrypt::Random::Source -e "print $Crypt::Random::Source::VERSION"' - if version < 0.13, vulnerableCheck Version:
perl -MCrypt::Random::Source -e "print $Crypt::Random::Source::VERSION"Verify Fix Applied:
Verify version is 0.13 or higher using same command and test random generation with sample script📡 Detection & Monitoring
Log Indicators:
- Application errors related to random source failures
- Cryptographic operation failures
Network Indicators:
- Predictable session tokens or nonces in network traffic
SIEM Query:
search for Perl application errors containing 'Crypt::Random::Source' or 'rand fallback'