New Self Extracting Package Created Via IExpress.EXE

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About the rule

Rule Type

Standard

Rule Description

Detects the "iexpress.exe" utility creating self-extracting packages. Attackers where seen leveraging "iexpress" to compile packages on the fly via ".sed" files. Investigate the command line options provided to "iexpress" and in case of a ".sed" file, check the contents and legitimacy of it.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND (PARENTPROCESSNAME endswith "\iexpress.exe" AND (PROCESSNAME endswith "\makecab.exe" OR ORIGINALFILENAME = "makecab.exe")) OR ((PROCESSNAME endswith "\iexpress.exe" OR ORIGINALFILENAME = "IEXPRESS.exe") AND COMMANDLINE contains " /n ") select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Joseliyo Sanchez, @Joseliyo_Jstnk