CVE-2022-31157
📋 TL;DR
This vulnerability affects the LTI 1.3 Tool Library for PHP, where insufficient cryptographic complexity in random nonce generation could allow attackers to predict or manipulate authentication values. It impacts any PHP application using this library for LTI 1.3 tool provider functionality. Users of affected versions are vulnerable to authentication-related attacks.
💻 Affected Systems
- LTI 1.3 Tool Library for PHP
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Authentication bypass leading to unauthorized access to LTI-integrated systems, potential data exposure, or privilege escalation within affected applications.
Likely Case
Session hijacking or replay attacks against LTI tool integrations, compromising user sessions and potentially accessing restricted educational resources.
If Mitigated
Limited impact with proper network segmentation and additional authentication layers, though the cryptographic weakness remains.
🎯 Exploit Status
Exploitation requires understanding of LTI protocol and cryptographic weaknesses, but no public exploit code is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.0
Vendor Advisory: https://github.com/packbackbooks/lti-1-3-php-library/security/advisories/GHSA-768m-5w34-2xf5
Restart Required: No
Instructions:
1. Update composer.json to require version 5.0 or higher of packbackbooks/lti-1-3-php-library. 2. Run 'composer update packbackbooks/lti-1-3-php-library'. 3. Test LTI functionality after update.
🧯 If You Can't Patch
- Implement additional authentication validation layers for LTI requests
- Monitor for unusual LTI session patterns and implement rate limiting
🔍 How to Verify
Check if Vulnerable:
Check composer.lock or vendor/packbackbooks/lti-1-3-php-library/composer.json for version number below 5.0Check Version:
composer show packbackbooks/lti-1-3-php-library | grep versionsVerify Fix Applied:
Confirm version 5.0 or higher is installed via 'composer show packbackbooks/lti-1-3-php-library'📡 Detection & Monitoring
Log Indicators:
- Multiple failed LTI authentication attempts from same source
- Unusual LTI session creation patterns
- LTI nonce reuse or predictable values
Network Indicators:
- Abnormal LTI launch request patterns
- Suspicious timing of LTI authentication requests
SIEM Query:
source="*lti*" AND (event="authentication_failure" OR event="session_hijack")