CVE-2020-22784
📋 TL;DR
This vulnerability in Etherpad's UeberDB MySQL connector allows attackers to bypass access controls by exploiting MySQL's behavior of omitting trailing spaces during string comparisons. Systems using UeberDB versions before 0.4.4 with MySQL backend are affected, potentially allowing unauthorized access to protected database records.
💻 Affected Systems
- Etherpad UeberDB
📦 What is this software?
Ueberdb by Etherpad
⚠️ Risk & Real-World Impact
Worst Case
Complete bypass of all access controls on key names, allowing attackers to read, modify, or delete any database records that should be protected by key-based access restrictions.
Likely Case
Partial access control bypass where attackers can access some protected records by manipulating key names with trailing spaces, potentially exposing sensitive data or allowing unauthorized modifications.
If Mitigated
Limited impact with proper network segmentation and additional authentication layers, though the fundamental access control bypass remains possible.
🎯 Exploit Status
Exploitation requires knowledge of the key naming scheme and access to the database interface. The vulnerability is in the comparison logic rather than requiring complex injection.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.4.4
Vendor Advisory: https://github.com/ether/ueberDB/commit/e8b58d03534ade8d83c2d1946a8350a23952531e
Restart Required: Yes
Instructions:
1. Update UeberDB to version 0.4.4 or later. 2. Restart the Etherpad service. 3. Verify the update was successful by checking the version.
🔧 Temporary Workarounds
Switch to non-MySQL database backend
allMigrate to PostgreSQL, SQLite, or another supported database backend that doesn't have the trailing space comparison issue.
Implement application-level key validation
allAdd custom validation to strip or reject keys with trailing spaces before database operations.
🧯 If You Can't Patch
- Implement strict network access controls to limit database access to trusted sources only
- Add additional authentication/authorization layers at the application level to compensate for the database-level access control bypass
🔍 How to Verify
Check if Vulnerable:
Check UeberDB version and database backend. If using MySQL and version < 0.4.4, the system is vulnerable.Check Version:
Check package.json or npm list ueberdb for version informationVerify Fix Applied:
Verify UeberDB version is 0.4.4 or higher and test that key-based access controls work correctly with trailing spaces.📡 Detection & Monitoring
Log Indicators:
- Unusual database access patterns
- Failed access attempts followed by successful access with similar key names
- Database queries with trailing spaces in key names
Network Indicators:
- Unusual database connection patterns from unexpected sources
- Increased database traffic to access-controlled tables
SIEM Query:
source="database_logs" AND (key_name LIKE "% " OR access_pattern="unusual")