Suspicious IIS URL GlobalRules Rewrite Via AppCmd

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About the rule

Rule Type

Standard

Rule Description

Detects usage of "appcmd" to create new global URL rewrite rules. This behaviour has been observed being used by threat actors to add new rules so they can access their webshells.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND (PROCESSNAME endswith "\appcmd.exe" OR ORIGINALFILENAME = "appcmd.exe") AND (COMMANDLINE contains "set" AND COMMANDLINE contains "config" AND COMMANDLINE contains "section:system.webServer/rewrite/globalRules" AND COMMANDLINE contains "commit:") select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Nasreddine Bencherchali (Nextron Systems)