CVE-2020-8510
📋 TL;DR
CVE-2020-8510 is an authentication bypass vulnerability in phpABook that allows attackers to log in as any user without a password by manipulating a cookie value. This affects all users of phpABook 0.9 Intermediate who have the application exposed. Attackers can gain administrative privileges and access sensitive contact data.
💻 Affected Systems
- phpABook
📦 What is this software?
Phpabook by Phpabook Project
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the phpABook instance, allowing attackers to access all contact data, modify user permissions, and potentially pivot to other systems if credentials are stored.
Likely Case
Unauthorized access to contact databases, data exfiltration, and privilege escalation to administrative functions.
If Mitigated
Limited impact if proper network segmentation and access controls prevent external exploitation.
🎯 Exploit Status
Exploitation requires setting a specific cookie value (userInfo=admin+1+en) on the login page. No special tools or skills needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://sourceforge.net/p/phpabook/news/
Restart Required: No
Instructions:
No official patch exists. Consider upgrading to a different contact management solution or implementing workarounds.
🔧 Temporary Workarounds
Cookie Validation
allImplement server-side validation of the userInfo cookie to ensure it cannot be manipulated to bypass authentication.
Modify PHP code to validate cookie values against database records
Session Management Enhancement
allImplement proper session management with secure session IDs and server-side session storage.
Implement PHP session management with session_regenerate_id() and secure session handling
🧯 If You Can't Patch
- Remove phpABook from internet-facing networks and restrict access to trusted internal IPs only.
- Implement a web application firewall (WAF) with rules to detect and block cookie manipulation attempts.
🔍 How to Verify
Check if Vulnerable:
Attempt to set a cookie named 'userInfo' with value 'admin+1+en' on the login page and check if you can access admin functions without credentials.Check Version:
Check the phpABook version in the application interface or configuration files.Verify Fix Applied:
After implementing workarounds, attempt the same cookie manipulation and verify authentication now fails.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful login with unusual cookie values
- Admin access from unexpected IP addresses
Network Indicators:
- HTTP requests containing 'userInfo=admin+1+en' cookie
- Unauthenticated requests to admin endpoints
SIEM Query:
source="web_logs" AND (cookie="*userInfo=admin+1+en*" OR (status=200 AND uri="/admin/*" AND NOT auth_success=true))