Suspicious ScreenSave Change by Reg.exe

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About the rule

Rule Type

Standard

Rule Description

Adversaries may establish persistence by executing malicious content triggered by user inactivity. Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND (PROCESSNAME endswith "\reg.exe" AND COMMANDLINE contains "HKEY_CURRENT_USER\Control Panel\Desktop,HKCU\Control Panel\Desktop") AND ((COMMANDLINE contains "/v ScreenSaveActive" AND COMMANDLINE contains "/t REG_SZ" AND COMMANDLINE contains "/d 1" AND COMMANDLINE contains "/f") OR (COMMANDLINE contains "/v ScreenSaveTimeout" AND COMMANDLINE contains "/t REG_SZ" AND COMMANDLINE contains "/d " AND COMMANDLINE contains "/f") OR (COMMANDLINE contains "/v ScreenSaverIsSecure" AND COMMANDLINE contains "/t REG_SZ" AND COMMANDLINE contains "/d 0" AND COMMANDLINE contains "/f") OR (COMMANDLINE contains "/v SCRNSAVE.EXE" AND COMMANDLINE contains "/t REG_SZ" AND COMMANDLINE contains "/d " AND COMMANDLINE contains ".scr" AND COMMANDLINE contains "/f")) 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