CVE-2021-3122
📋 TL;DR
CVE-2021-3122 is a critical remote code execution vulnerability in NCR Command Center Agent (CMCAgent) on Aloha POS/BOH servers. It allows unauthenticated attackers to execute arbitrary commands as SYSTEM by sending specially crafted XML to port 8089. This affects organizations using NCR Aloha point-of-sale systems with vulnerable configurations.
💻 Affected Systems
- NCR Command Center Agent (CMCAgent)
- NCR Aloha POS/BOH servers
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install malware, steal payment card data, disrupt business operations, and pivot to other network systems.
Likely Case
Ransomware deployment, data exfiltration, or installation of persistent backdoors on POS systems.
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation attempts.
🎯 Exploit Status
Actively exploited in the wild since 2020/2021. Simple XML-based exploit requiring minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 16.3.1 or later (contact NCR for specific patched versions)
Vendor Advisory: https://www.ncr.com/security
Restart Required: Yes
Instructions:
1. Contact NCR support for patched version. 2. Backup system. 3. Apply patch following NCR instructions. 4. Restart affected services/systems. 5. Verify patch application.
🔧 Temporary Workarounds
Block Port 8089
allBlock inbound access to port 8089 at network perimeter and internally.
Windows Firewall: netsh advfirewall firewall add rule name="Block CMC Port" dir=in action=block protocol=TCP localport=8089
Linux iptables: iptables -A INPUT -p tcp --dport 8089 -j DROP
Disable CMCAgent Service
windowsTemporarily disable the vulnerable CMCAgent service if not required.
sc stop CMCAgent
sc config CMCAgent start= disabled
🧯 If You Can't Patch
- Implement strict network segmentation isolating POS systems from other networks
- Deploy host-based intrusion detection and monitor for suspicious process creation
🔍 How to Verify
Check if Vulnerable:
Check if port 8089 is listening and CMCAgent version is 16.3: netstat -an | findstr :8089 and check service version in Programs and FeaturesCheck Version:
wmic product where name="NCR Command Center Agent" get versionVerify Fix Applied:
Verify port 8089 is no longer accessible or service is updated: netstat -an | findstr :8089 and check for patched version📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from CMCAgent
- XML payloads sent to port 8089
- Failed authentication attempts to CMCAgent
Network Indicators:
- Inbound connections to port 8089 from unexpected sources
- XML data containing 'runCommand' parameter sent to port 8089
SIEM Query:
destination_port:8089 AND (xml_content:*runCommand* OR process_name:cmd.exe OR process_name:powershell.exe)🔗 References
- https://github.com/roughb8722/CVE-2021-3122-Details/blob/main/CVE-2021-3122
- https://rdf2.alohaenterprise.com/client/CMCInst.zip
- https://www.tetradefense.com/incident-response-services/active-exploit-a-remote-code-execution-rce-vulnerability-for-ncr-aloha-point-of-sale/
- https://github.com/roughb8722/CVE-2021-3122-Details/blob/main/CVE-2021-3122
- https://rdf2.alohaenterprise.com/client/CMCInst.zip
- https://www.tetradefense.com/incident-response-services/active-exploit-a-remote-code-execution-rce-vulnerability-for-ncr-aloha-point-of-sale/
