Malicious CHM File Delivered via HTTP
This rule detects the delivery of a Compiled HTML Help (CHM) file via HTTP that contains the string "ITSF" within its file data. CHM files can be used to deliver malicious content, and the presence of "ITSF" (likely indicating an InfoTech Storage Format header) combined with HTTP delivery suggests a potential attempt to bypass security controls or execute malicious code. This is often associated with T1218.001 (Signed Binary Proxy Execution: Compiled HTML Help) from the MITRE ATT&CK framework.
Suricata
