Kimsuky JavaScript Dropper Activity

Aamir Muhammad@Aamir

•updated Mar 25, 2026•5•0•58

This rule detects various activities associated with the Kimsuky JavaScript dropper, including DNS requests to known malicious domains, creation of specific files (Themes.js, L298306.tmp), execution of certutil.exe or script.exe for decoding/encoding, suspicious command-line arguments for system information or task listing, and persistence mechanisms via scheduled tasks or registry modifications related to 'Themes.js' or 'Windows Theme Manager'.