CVE-2018-16115
📋 TL;DR
CVE-2018-16115 is a cryptographic vulnerability in Lightbend Akka 2.5.x that allows attackers to compromise TLS-secured communications when custom random number generators are enabled. The bug causes predictable random number generation, enabling message disclosure, modification, and replay attacks. Only Akka deployments using the vulnerable AES128CounterSecureRNG or AES256CounterSecureRNG configurations are affected.
💻 Affected Systems
- Lightbend Akka
📦 What is this software?
Akka by Lightbend
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of all Akka Remoting/Cluster communications including eavesdropping, message modification, replay attacks, and potential data exfiltration or system takeover.
Likely Case
Unauthorized access to sensitive data transmitted between Akka nodes, potential message manipulation in distributed systems.
If Mitigated
No impact if using default RNG configuration or properly patched versions.
🎯 Exploit Status
Exploitation requires network access to Akka Remoting endpoints and knowledge of the vulnerable configuration. The cryptographic weakness makes attacks feasible for skilled adversaries.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Akka 2.5.16 and later
Vendor Advisory: https://doc.akka.io/docs/akka/current/security/2018-08-29-aes-rng.html
Restart Required: Yes
Instructions:
1. Upgrade to Akka 2.5.16 or later. 2. Remove any configuration references to AES128CounterSecureRNG or AES256CounterSecureRNG. 3. Restart all Akka applications and nodes. 4. Verify configuration uses default secure RNG.
🔧 Temporary Workarounds
Disable vulnerable RNG configurations
allRemove custom RNG configurations to revert to default secure random number generator
Remove or comment out any 'akka.remote.artery.advanced.random-number-generator' or 'akka.remote.classic.security.random-number-generator' configurations referencing AES128CounterSecureRNG or AES256CounterSecureRNG
🧯 If You Can't Patch
- Immediately disable AES128CounterSecureRNG and AES256CounterSecureRNG configurations and revert to default RNG
- Isolate Akka Remoting traffic to trusted networks only and implement additional network-level encryption
🔍 How to Verify
Check if Vulnerable:
Check Akka configuration files for references to AES128CounterSecureRNG or AES256CounterSecureRNG in random-number-generator settings. Verify Akka version is between 2.5.0 and 2.5.15.Check Version:
Check application logs for Akka version or use: java -cp "akka-actor_2.12-*.jar" -Dakka.version.checkVerify Fix Applied:
Confirm Akka version is 2.5.16 or higher and configuration files contain no references to the vulnerable RNG implementations.📡 Detection & Monitoring
Log Indicators:
- Configuration warnings about deprecated or insecure RNG
- Unexpected connection resets or TLS handshake failures in Akka Remoting
Network Indicators:
- Unusual patterns in encrypted traffic between Akka nodes
- Repeated cryptographic nonces or initialization vectors
SIEM Query:
Search for configuration files containing 'AES128CounterSecureRNG' OR 'AES256CounterSecureRNG' in path patterns matching Akka deployments