CVE-2021-33668
📋 TL;DR
CVE-2021-33668 is an LDAP injection vulnerability in SAP's SCIMono software that allows unauthenticated attackers to inject malicious LDAP queries. This could lead to partial information disclosure from LDAP directories. Organizations using affected versions of SCIMono are vulnerable.
💻 Affected Systems
- SAP SCIMono
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete LDAP directory enumeration leading to exposure of sensitive user data, organizational structure, and potentially credential harvesting.
Likely Case
Partial information disclosure from LDAP queries, potentially revealing user attributes, group memberships, or limited directory information.
If Mitigated
No impact if proper input validation and LDAP query sanitization are implemented.
🎯 Exploit Status
LDAP injection is a well-known attack vector with established exploitation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.12.0 and later
Vendor Advisory: https://github.com/SAP/scimono/security/advisories/GHSA-wg9g-w4fg-3qqc
Restart Required: Yes
Instructions:
1. Upgrade SCIMono to version 1.12.0 or later. 2. Restart the SCIMono service. 3. Verify the upgrade was successful.
🔧 Temporary Workarounds
Input Validation Filter
allImplement custom input validation to sanitize LDAP query parameters
Implement parameterized LDAP queries in application code
Network Segmentation
allRestrict access to SCIMono instances to trusted networks only
Configure firewall rules to limit access to SCIMono ports
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block LDAP injection patterns
- Disable or restrict LDAP functionality in SCIMono if not required
🔍 How to Verify
Check if Vulnerable:
Check SCIMono version - if below 1.12.0, the system is vulnerableCheck Version:
Check SCIMono application logs or configuration for version informationVerify Fix Applied:
Verify SCIMono version is 1.12.0 or higher and test LDAP query functionality📡 Detection & Monitoring
Log Indicators:
- Unusual LDAP query patterns
- Malformed LDAP requests
- Failed authentication attempts with special characters
Network Indicators:
- LDAP queries containing special characters like *, (, ), &, |, =, !
SIEM Query:
source="scimono" AND (message="*LDAP*" OR message="*query*") AND (message="*)*" OR message="*(*" OR message="*&*" OR message="*|*")