Techniques
Sample rules
Windows Replication Through Removable Media
- source: splunk
- technicques:
- T1091
Description
The following analytic detects the creation or dropping of executable or script files in the root directory of a removable drive. It leverages data from the Endpoint.Filesystem datamodel, focusing on specific file types and their creation paths. This activity is significant as it may indicate an attempt to spread malware, such as ransomware, via removable media. If confirmed malicious, this behavior could lead to unauthorized code execution, lateral movement, or persistence within the network, potentially compromising sensitive data and systems.
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`
Executables Or Script Creation In Suspicious Path
- source: splunk
- technicques:
- T1036
Description
The following analytic identifies the creation of executables or scripts in suspicious file paths on Windows systems. It leverages the Endpoint.Filesystem data model to detect files with specific extensions (e.g., .exe, .dll, .ps1) created in uncommon directories (e.g., \windows\fonts, \users\public). This activity is significant as adversaries often use these paths to evade detection and maintain persistence. If confirmed malicious, this behavior could allow attackers to execute unauthorized code, escalate privileges, or persist within the environment, posing a significant security threat.
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 IN ("*.exe", "*.dll", "*.sys", "*.com", "*.vbs", "*.vbe", "*.js", "*.ps1", "*.bat", "*.cmd", "*.pif") AND Filesystem.file_path IN ("*\\windows\\fonts\\*", "*\\windows\\temp\\*", "*\\users\\public\\*", "*\\windows\\debug\\*", "*\\Users\\Administrator\\Music\\*", "*\\Windows\\servicing\\*", "*\\Users\\Default\\*", "*Recycle.bin*", "*\\Windows\\Media\\*", "*\\Windows\\repair\\*", "*\\AppData\\Local\\Temp*", "*\\PerfLogs\\*", "*:\\temp\\*") 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`