CVE-2021-21469
📋 TL;DR
This vulnerability in SAP NetWeaver Master Data Management allows attackers to set custom UNC paths in MDS server configuration, potentially enabling SMB relay attacks. When security guidelines aren't followed (e.g., missing MDS Server password, insecure configurations), attackers can access sensitive data. Organizations running SAP NetWeaver MDM on Windows without proper security controls are affected.
💻 Affected Systems
- SAP NetWeaver Master Data Management
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through SMB relay attacks leading to full information disclosure, credential theft, and potential lateral movement within the network.
Likely Case
Unauthorized access to sensitive master data and configuration information, potentially exposing business-critical data.
If Mitigated
Minimal impact with proper security controls in place, as the attack requires multiple security misconfigurations to succeed.
🎯 Exploit Status
Exploitation requires specific misconfigurations and knowledge of the target environment. SMB relay attacks are well-known techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply SAP Security Note 2993032
Vendor Advisory: https://launchpad.support.sap.com/#/notes/2993032
Restart Required: Yes
Instructions:
1. Review SAP Security Note 2993032. 2. Apply the security patch through SAP Solution Manager or manual update. 3. Restart affected services. 4. Verify security guidelines are implemented.
🔧 Temporary Workarounds
Implement Security Guidelines
windowsFollow SAP security guidelines for MDS server configuration including setting MDS Server password and securing network/OS configurations.
Restrict UNC Path Access
windowsConfigure Windows security policies to restrict UNC path access and prevent SMB relay attacks.
Configure Windows Firewall to block SMB traffic from untrusted networks
Set RestrictAnonymous registry settings
🧯 If You Can't Patch
- Implement all SAP security guidelines for MDS server configuration
- Isolate affected systems from untrusted networks and implement network segmentation
🔍 How to Verify
Check if Vulnerable:
Check if MDS Server password is set and review security configurations against SAP guidelines. Verify if custom UNC paths can be configured without authentication.Check Version:
Check SAP system version through transaction SM51 or system informationVerify Fix Applied:
Verify SAP Security Note 2993032 is applied and security guidelines are properly implemented. Test that UNC path configuration requires proper authentication.📡 Detection & Monitoring
Log Indicators:
- Unauthorized configuration changes to MDS server
- SMB authentication attempts from unusual sources
- UNC path access attempts
Network Indicators:
- SMB traffic patterns indicative of relay attacks
- Unauthorized UNC path requests
SIEM Query:
Search for event IDs related to SMB authentication failures, UNC path access, or MDS configuration changes