LoFP / the uninstallation of a large software application or the use of cleanmgr.exe may trigger this detection. a filter is necessary to reduce false positives.

Techniques

• T1485

Sample rules

Windows Data Destruction Recursive Exec Files Deletion

• source: splunk
• technicques:
  • T1485

Description

The following analytic identifies a suspicious process that is recursively deleting executable files on a compromised host. It leverages Sysmon Event Codes 23 and 26 to detect this activity by monitoring for a high volume of deletions or overwrites of files with extensions like .exe, .sys, and .dll. This behavior is significant as it is commonly associated with destructive malware such as CaddyWiper, DoubleZero, and SwiftSlicer, which aim to make file recovery impossible. If confirmed malicious, this activity could lead to significant data loss and system instability, severely impacting business operations.

Detection logic

`sysmon` EventCode IN ("23","26") TargetFilename IN ("*.exe", "*.sys", "*.dll") 
| bin _time span=2m 
| stats count, values(TargetFilename) as deleted_files, min(_time) as firstTime, max(_time) as lastTime by user, dest, signature, signature_id, Image, process_name, process_guid 
| rename Image as process 
| where count >=100 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_data_destruction_recursive_exec_files_deletion_filter`