Detect Rockwell Automation Logix Controllers Insufficient Credential Protection (CVE-2021-22681) in Microsoft Sentinel
CVE-2021-22681 is an insufficient protection of credentials vulnerability (CWE-522) affecting Rockwell Automation multiple products including Logix controllers. An attacker can intercept or obtain weakly protected credentials used to authenticate with Logix controllers, enabling authentication bypass. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog and poses critical risk in OT/ICS environments where unauthorized controller access could cause process disruption or physical damage.
MITRE ATT&CK
KQL Detection Query
union DeviceNetworkEvents, CommonSecurityLog
| where TimeGenerated >= ago(7d)
| where DestinationPort in (44818, 2222, 2221) or ApplicationProtocol =~ "EtherNet/IP" or ApplicationProtocol =~ "CIP"
| where DeviceVendor =~ "Rockwell" or DeviceProduct has_any ("Logix", "ControlLogix", "CompactLogix", "GuardLogix", "SoftLogix", "DriveLogix")
| extend AuthAttempt = iff(Message has_any ("login", "authenticate", "credential", "password", "session"), true, false)
| where AuthAttempt == true or DestinationPort == 44818
| project TimeGenerated, DeviceName, SourceIP, DestinationIP, DestinationPort, ApplicationProtocol, Message, DeviceProduct, AdditionalExtensions
| order by TimeGenerated descDetects network activity targeting Rockwell Automation Logix controllers on EtherNet/IP (port 44818) and CIP protocol ports, flagging authentication-related events that may indicate exploitation of CVE-2021-22681 insufficient credential protection.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate engineering workstation connections to Logix controllers for routine programming or monitoring
- Scheduled backups or asset inventory scans using EtherNet/IP
- OEM vendor remote access sessions for maintenance
- Network monitoring tools polling controller status via CIP
Other platforms for CVE-2021-22681
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1EtherNet/IP Controller Enumeration via nmap
Expected signal: Network connection events from the scanning host to port 44818 on multiple destination IPs; IDS alerts for CIP/EtherNet/IP enumeration
- Test 2CIP Session Credential Capture via Wireshark
Expected signal: Passive capture produces no active network events; detection depends on promiscuous mode detection or IDS passive analysis alerts
- Test 3RSLinx Classic Unauthorized Connection Attempt
Expected signal: Windows process creation for RSLinx.exe; network connection from non-engineering workstation to controller port 44818; controller audit log entry for unauthorized connection attempt
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