CVE-2021-25644
📋 TL;DR
CVE-2021-25644 is an information disclosure vulnerability in Couchbase Server where incorrect REST API commands cause authentication credentials to be logged in cleartext in debug.log and info.log files, and displayed in the administrator UI. This affects Couchbase Server administrators and potentially anyone with access to log files or the admin interface. The vulnerability exposes sensitive authentication information that could be used for further attacks.
💻 Affected Systems
- Couchbase Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers obtain administrative credentials, gain full control of Couchbase Server, access sensitive data, and potentially pivot to other systems.
Likely Case
Unauthorized users with log file access or UI visibility obtain authentication credentials, leading to unauthorized database access and potential data exfiltration.
If Mitigated
With proper access controls and monitoring, credential exposure is limited to authorized administrators only, minimizing exploitation risk.
🎯 Exploit Status
Exploitation requires sending specific incorrect commands to the REST API; no authentication bypass needed but requires API access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.6.2 and later, 7.0.0 GA and later
Vendor Advisory: https://www.couchbase.com/resources/security#SecurityAlerts
Restart Required: Yes
Instructions:
1. Download patched version from Couchbase downloads page. 2. Backup configuration and data. 3. Stop Couchbase Server. 4. Install updated version. 5. Restart Couchbase Server. 6. Verify functionality.
🔧 Temporary Workarounds
Disable debug logging
allPrevents credentials from being written to debug.log files
Edit Couchbase logging configuration to set debug level to INFO or higher
Restrict REST API access
allLimit who can send commands to the vulnerable REST API endpoints
Configure firewall rules or network ACLs to restrict access to Couchbase REST API ports
🧯 If You Can't Patch
- Implement strict access controls on log directories and admin UI
- Monitor log files for credential leakage patterns and implement alerting
🔍 How to Verify
Check if Vulnerable:
Check Couchbase Server version; if running 5.x, 6.0-6.6.1, or 7.0.0 Beta, system is vulnerable.Check Version:
couchbase-server --version or check web admin consoleVerify Fix Applied:
Verify version is 6.6.2+ or 7.0.0 GA+; test that incorrect REST API commands no longer leak credentials in logs or UI.📡 Detection & Monitoring
Log Indicators:
- Cleartext authentication strings in debug.log or info.log files
- Suspicious REST API error messages containing credential data
Network Indicators:
- Unusual patterns of incorrect REST API commands to Couchbase endpoints
SIEM Query:
source="couchbase.log" AND ("password" OR "auth" OR "credential") AND "cleartext"