Wlrmdr.EXE Uncommon Argument Or Child Process
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About the rule
Rule Type
Standard
Rule Description
Detects the execution of "Wlrmdr.exe" with the "-u" command line flag which allows anything passed to it to be an argument of the ShellExecute API, which would allow an attacker to execute arbitrary binaries. This detection also focuses on any uncommon child processes spawned from "Wlrmdr.exe" as a supplement for those that posses "ParentImage" telemetry.
Severity
Trouble
Rule Requirement
Criteria
Action1: actionname = "Process started" AND PARENTPROCESSNAME endswith "\wlrmdr.exe" OR (((PROCESSNAME endswith "\wlrmdr.exe" OR ORIGINALFILENAME = "WLRMNDR.EXE") AND (COMMANDLINE contains "-s ,/s ,–s ,—s ,―s " AND COMMANDLINE contains "-f ,/f ,–f ,—f ,―f " AND COMMANDLINE contains "-t ,/t ,–t ,—t ,―t " AND COMMANDLINE contains "-m ,/m ,–m ,—m ,―m " AND COMMANDLINE contains "-a ,/a ,–a ,—a ,―a " AND COMMANDLINE contains "-u ,/u ,–u ,—u ,―u ")) AND (PARENTPROCESSNAME != "C:\Windows\System32\winlogon.exe" AND PARENTPROCESSNAME != ",-" AND isExist(PARENTPROCESSNAME))) select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME
Detection
Execution Mode
realtime
Log Sources
Windows
Author
frack113, manasmbellani
