Techniques
Sample rules
Windows Files and Dirs Access Rights Modification Via Icacls
- source: splunk
- technicques:
- T1222.001
Description
The following analytic identifies the modification of security permissions on files or directories using tools like icacls.exe, cacls.exe, or xcacls.exe. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line executions. This activity is significant as it is commonly used by Advanced Persistent Threats (APTs) and coinminer scripts to evade detection and maintain control over compromised systems. If confirmed malicious, this behavior could allow attackers to hinder investigation, impede remediation efforts, and maintain persistent access to the compromised environment.
Detection logic
| tstats `security_content_summariesonly` min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where
Processes.process_name IN ("icacls.exe", "cacls.exe","xcacls.exe") AND
Processes.process IN ("*:R*", "*:W*", "*:F*", "*:C*", "*:N*", "*/P*", "*/E*")
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)`
| `windows_files_and_dirs_access_rights_modification_via_icacls_filter`
Icacls Deny Command
- source: splunk
- technicques:
- T1222
Description
The following analytic detects instances where an adversary modifies security permissions of a file or directory using commands like “icacls.exe”, “cacls.exe”, or “xcacls.exe” with deny options. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity is significant as it is commonly used by Advanced Persistent Threats (APTs) and coinminer scripts to evade detection and impede access to critical files. If confirmed malicious, this could allow attackers to maintain persistence and hinder incident response efforts.
Detection logic
| tstats `security_content_summariesonly` min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where
Processes.process_name IN ( "icacls.exe", "cacls.exe", "xcacls.exe") AND
Processes.process IN ("*/deny*", "*/d:*", "*/d ")
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)`
| `icacls_deny_command_filter`