CVE-2023-40764
📋 TL;DR
This vulnerability in PHP Jabbers Car Rental Script v3.0 allows attackers to enumerate valid user accounts through the password recovery feature. By observing differences in error messages, attackers can determine which usernames/emails exist in the system, enabling targeted brute force attacks. This affects all deployments of the vulnerable software version.
💻 Affected Systems
- PHP Jabbers Car Rental Script
📦 What is this software?
Car Rental Script by Phpjabbers
⚠️ Risk & Real-World Impact
Worst Case
Attackers identify all valid user accounts, then conduct successful credential stuffing or brute force attacks leading to account compromise, potential data theft, and unauthorized access to the car rental system.
Likely Case
Attackers enumerate some user accounts and attempt password attacks, potentially gaining access to user accounts with weak credentials.
If Mitigated
User enumeration is prevented, forcing attackers to attempt brute force against both valid and invalid accounts equally, significantly reducing attack effectiveness.
🎯 Exploit Status
The vulnerability is simple to exploit by comparing password recovery response messages.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.phpjabbers.com/car-rental-script/
Restart Required: No
Instructions:
Check vendor website for updated version. If unavailable, implement workarounds.
🔧 Temporary Workarounds
Standardize Password Recovery Messages
allModify the password recovery functionality to return identical messages regardless of whether the user exists.
Edit PHP files handling password recovery to use generic messages like 'If this email exists in our system, you will receive recovery instructions.'
Implement Rate Limiting
allAdd rate limiting to password recovery requests to prevent automated enumeration.
Implement IP-based or session-based request limiting in the password recovery script.
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to detect and block user enumeration patterns.
- Monitor authentication logs for unusual patterns of password recovery requests.
🔍 How to Verify
Check if Vulnerable:
Test password recovery with valid and invalid emails/usernames. If responses differ (e.g., 'user not found' vs 'email sent'), the system is vulnerable.Check Version:
Check the script version in admin panel or configuration files.Verify Fix Applied:
After applying fixes, test password recovery again. Both valid and invalid inputs should return identical generic messages.📡 Detection & Monitoring
Log Indicators:
- Multiple failed password recovery attempts from single IP
- Patterns of sequential username/email attempts in recovery logs
Network Indicators:
- Unusual volume of POST requests to password recovery endpoint
SIEM Query:
source="web_logs" AND uri="/password-recovery.php" AND status=200 | stats count by src_ip