Techniques
Sample rules
Windows WinLogon with Public Network Connection
- source: splunk
- technicques:
- T1542.003
Description
The following analytic is designed to detect anomalous behavior associated with the BlackLotus Campaign, a sophisticated bootkit attack reported by ESET and further investigated in a blog by Microsoft, which provided hunting queries for security analysts. The primary focus of this analytic is to identify instances of Winlogon.exe, a critical Windows process, connecting to public IP space, which is indicative of potential malicious activity.\ The BlackLotus Campaign is a bootkit-based attack that compromises system integrity by infecting the Master Boot Record (MBR) and Volume Boot Record (VBR). This malware variant can bypass traditional security measures, load before the operating system, and maintain persistence on the target system. Winlogon.exe is a critical Windows process responsible for managing user logon and logoff processes. Under normal circumstances, Winlogon.exe should not be connecting to public IP addresses. However, if it does, it may indicate that the process has been compromised as part of the BlackLotus Campaign or another malicious operation. This analytic monitors network connections made by Winlogon.exe and triggers an alert if it detects connections to public IP space. By identifying such anomalous behavior, security analysts can investigate further and respond swiftly to potential threats.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name IN (winlogon.exe) Processes.process!=unknown by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| join process_id [
| tstats `security_content_summariesonly` count FROM datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port != 0 NOT (All_Traffic.dest IN (127.0.0.1,10.0.0.0/8,172.16.0.0/12, 192.168.0.0/16, 0:0:0:0:0:0:0:1)) by All_Traffic.process_id All_Traffic.dest All_Traffic.dest_port
| `drop_dm_object_name(All_Traffic)`
| rename dest as publicIp ]
| table dest parent_process_name process_name process_path process process_id dest_port publicIp
| `windows_winlogon_with_public_network_connection_filter`