Techniques
Sample rules
Executables Or Script Creation In Suspicious Path
- source: splunk
- technicques:
- T1036
Description
This analytic identifies potentially malicious executables or scripts by examining a list of suspicious file paths on Windows Operating System. The purpose of this technique is to uncover files with known file extensions that could be used by adversaries to evade detection and persistence. The suspicious file paths selected for investigation are typically uncommon and uncommonly associated with executable or script files. By scrutinizing these paths, we can proactively identify potential security threats and enhance overall system security.
Detection logic
|tstats `security_content_summariesonly` values(Filesystem.file_path) as file_path count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where (Filesystem.file_name = *.exe OR Filesystem.file_name = *.dll OR Filesystem.file_name = *.sys OR Filesystem.file_name = *.com OR Filesystem.file_name = *.vbs OR Filesystem.file_name = *.vbe OR Filesystem.file_name = *.js OR Filesystem.file_name = *.ps1 OR Filesystem.file_name = *.bat OR Filesystem.file_name = *.cmd OR Filesystem.file_name = *.pif) AND ( Filesystem.file_path = *\\windows\\fonts\\* OR Filesystem.file_path = *\\windows\\temp\\* OR Filesystem.file_path = *\\users\\public\\* OR Filesystem.file_path = *\\windows\\debug\\* OR Filesystem.file_path = *\\Users\\Administrator\\Music\\* OR Filesystem.file_path = *\\Windows\\servicing\\* OR Filesystem.file_path = *\\Users\\Default\\* OR Filesystem.file_path = *Recycle.bin* OR Filesystem.file_path = *\\Windows\\Media\\* OR Filesystem.file_path = *\\Windows\\repair\\* OR Filesystem.file_path = *\\AppData\\Local\\Temp* OR Filesystem.file_path = *\\PerfLogs\\*) by Filesystem.file_create_time Filesystem.process_id Filesystem.file_name Filesystem.user
| `drop_dm_object_name(Filesystem)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `executables_or_script_creation_in_suspicious_path_filter`
Windows Replication Through Removable Media
- source: splunk
- technicques:
- T1091
Description
This analytic is developed to detect suspicious executable or script files created or dropped in the root drive of a targeted host. This technique is commonly used by threat actors, adversaries or even red teamers to replicate or spread in possible removable drives. Back then, WORM malware was popular for this technique where it would drop a copy of itself in the root drive to be able to spread or to have a lateral movement in other network machines. Nowadays, Ransomware like CHAOS ransomware also use this technique to spread its malicious code in possible removable drives. This TTP detection can be a good indicator that a process might create a persistence technique or lateral movement of a targeted machine. We suggest checking the process name that creates this event, the file created, user type, and the reason why that executable or scripts are dropped in the root drive.
Detection logic
|tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where (Filesystem.file_name = *.exe OR Filesystem.file_name = *.dll OR Filesystem.file_name = *.sys OR Filesystem.file_name = *.com OR Filesystem.file_name = *.vbs OR Filesystem.file_name = *.vbe OR Filesystem.file_name = *.js OR Filesystem.file_name= *.bat OR Filesystem.file_name = *.cmd OR Filesystem.file_name = *.pif) by Filesystem.file_create_time Filesystem.process_id Filesystem.file_name Filesystem.file_path Filesystem.user Filesystem.dest
| `drop_dm_object_name(Filesystem)`
| eval dropped_file_path = split(file_path, "\\")
| eval dropped_file_path_split_count = mvcount(dropped_file_path)
| eval root_drive = mvindex(dropped_file_path,0)
| where LIKE(root_drive, "%:") AND dropped_file_path_split_count = 2 AND root_drive!= "C:"
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_replication_through_removable_media_filter`