LoFP LoFP / no false positives known. filter as needed.

Techniques

Sample rules

Windows Spearphishing Attachment Onenote Spawn Mshta

Description

The following analytic detects OneNote spawning mshta.exe, a behavior often associated with spearphishing attacks. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where OneNote is the parent process. This activity is significant as it is commonly used by malware families like TA551, AsyncRat, Redline, and DCRAT to execute malicious scripts. If confirmed malicious, this could allow attackers to execute arbitrary code, potentially leading to data exfiltration, system compromise, or further malware deployment. Immediate investigation and containment are recommended.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name IN ("onenote.exe", "onenotem.exe") `process_mshta` by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_spearphishing_attachment_onenote_spawn_mshta_filter`