this detection should yield little or no false positive results. it is uncommon for lnk files to be executed from temporary or user directories.

Techniques

T1566.002

Sample rules

Process Creating LNK file in Suspicious Location

source: splunk
technicques:
- T1566.002

Description

The following analytic detects a process creating a .lnk file in suspicious locations such as C:\User* or *\Local\Temp\*. It leverages filesystem and process activity data from the Endpoint data model to identify this behavior. This activity is significant because creating .lnk files in these directories is a common tactic used by spear phishing tools to establish persistence or execute malicious payloads. If confirmed malicious, this could allow an attacker to maintain persistence, execute arbitrary code, or further compromise the system.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_name="*.lnk" AND (Filesystem.file_path="C:\\Users\\*" OR Filesystem.file_path="*\\Temp\\*") by _time span=1h Filesystem.process_guid Filesystem.file_name Filesystem.file_path Filesystem.file_hash Filesystem.user 
| `drop_dm_object_name(Filesystem)` 
| rename process_guid as lnk_guid 
| join lnk_guid _time [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_name=* by _time span=1h Processes.parent_process_name Processes.parent_process_guid Processes.process_name Processes.dest Processes.process Processes.path 
| `drop_dm_object_name(Processes)` 
| rename parent_process_guid as lnk_guid] 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| table firstTime, lastTime, lnk_guid, user, dest, file_name, file_path, process_name, process, process_path, file_hash 
| `process_creating_lnk_file_in_suspicious_location_filter`