LoFP LoFP / it is not uncommon for outlook to write legitimate zip files to the disk.

Techniques

Sample rules

Detect Outlook exe writing a zip file

Description

This search looks for execution of process outlook.exe where the process is writing a .zip file to the disk.

Detection logic


| tstats `security_content_summariesonly`  min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where Processes.process_name=outlook.exe by _time span=5m Processes.parent_process_id Processes.process_id Processes.dest Processes.process_name Processes.parent_process_name Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| rename process_id as malicious_id
| rename parent_process_id as outlook_id
| join malicious_id type=inner[
| tstats `security_content_summariesonly` count values(Filesystem.file_path) as file_path values(Filesystem.file_name) as file_name  FROM datamodel=Endpoint.Filesystem where (Filesystem.file_path=*.zip*   OR Filesystem.file_name=*.lnk ) AND (Filesystem.file_path=C:\\Users* OR Filesystem.file_path=*Local\\Temp*) by  _time span=5m Filesystem.process_id Filesystem.file_hash Filesystem.dest  
| `drop_dm_object_name(Filesystem)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| rename process_id as malicious_id
| fields malicious_id outlook_id dest file_path file_name file_hash count file_id] 
| table firstTime lastTime user malicious_id outlook_id process_name parent_process_name file_name  file_path 
| where file_name != "" 
| `detect_outlook_exe_writing_a_zip_file_filter`