it is possible false positives may be present based on the internal name dcinst.exe, filter as needed. it may be worthy to alert on the service name.

Techniques

T1486

Sample rules

Windows DiskCryptor Usage

source: splunk
technicques:
- T1486

Description

The following analytic detects the execution of DiskCryptor, identified by the process names “dcrypt.exe” or “dcinst.exe”. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and original file names. DiskCryptor is significant because adversaries use it to manually encrypt disks during an operation, potentially leading to data inaccessibility. If confirmed malicious, this activity could result in complete disk encryption, causing data loss and operational disruption. Immediate investigation is required to mitigate potential ransomware attacks.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE (
        Processes.process_name="dcrypt.exe"
        OR
        Processes.original_file_name=dcinst.exe
    )
  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_diskcryptor_usage_filter`