Techniques
Sample rules
Modify ACL permission To Files Or Folder
- source: splunk
- technicques:
- T1222
Description
The following analytic detects the modification of ACL permissions to files or folders, making them accessible to everyone or to system account. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on processes like “cacls.exe,” “icacls.exe,” and “xcacls.exe” with specific command-line arguments. This activity is significant as it may indicate an adversary attempting to evade ACLs or access protected files. If confirmed malicious, this could allow unauthorized access to sensitive data, potentially leading to data breaches or further system compromise.
Detection logic
| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.process_id) as process_id count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name = "cacls.exe" OR Processes.process_name = "icacls.exe" OR Processes.process_name = "xcacls.exe") AND Processes.process = "*/G*" AND (Processes.process = "* everyone:*" OR Processes.process = "* SYSTEM:*" OR Processes.process = "* S-1-1-0:*") by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `modify_acl_permission_to_files_or_folder_filter`