Added detection testing service results inWindows DiskCryptor Usage

This commit is contained in:
root
2021-11-15 22:17:34 +00:00
parent 4ec3670291
commit 8f6fe7cc45
@@ -6,22 +6,33 @@ author: Michael Haag, Splunk
type: Hunting
datamodel:
- Endpoint
description: 'The following analytic identifies DiskCryptor process name of dcrypt.exe or internal name dcinst.exe. This utility has been utilized by adversaries to encrypt disks manually during an operation. In addition, during install, a dcrypt.sys driver is installed and requires a reboot in order to take effect. There are no command-line arguments used.'
description: The following analytic identifies DiskCryptor process name of dcrypt.exe
or internal name dcinst.exe. This utility has been utilized by adversaries to encrypt
disks manually during an operation. In addition, during install, a dcrypt.sys driver
is installed and requires a reboot in order to take effect. There are no command-line
arguments used.
search: '| 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.dest Processes.user Processes.parent_process_name Processes.process_name Processes.original_file_name
Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` | `windows_diskcryptor_usage_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
known_false_positives: 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.
as lastTime from datamodel=Endpoint.Processes where (Processes.process_name="dcrypt.exe"
OR Processes.original_file_name=dcinst.exe) by Processes.dest Processes.user Processes.parent_process_name
Processes.process_name Processes.original_file_name Processes.process Processes.process_id
Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` | `windows_diskcryptor_usage_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information
on process that include the name of the process responsible for the changes from
your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
endpoint product.
known_false_positives: 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.
references:
- https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/
- https://github.com/DavidXanatos/DiskCryptor
- https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/
- https://github.com/DavidXanatos/DiskCryptor
tags:
analytic_story:
- Ransomware
dataset: []
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1486/dcrypt/windows-sysmon.log
kill_chain_phases:
- Exploitation
mitre_attack_id:
@@ -34,11 +45,11 @@ tags:
- _time
- Processes.dest
- Processes.user
- Processes.parent_process_name #parent process name
- Processes.parent_process #parent cmdline
- Processes.parent_process_name
- Processes.parent_process
- Processes.original_file_name
- Processes.process_name #process name
- Processes.process #process cmdline
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_path
- Processes.process_path
@@ -46,12 +57,12 @@ tags:
security_domain: endpoint
impact: 70
confidence: 50
# (impact * confidence)/100
risk_score: 35
context:
- Source:Endpoint
- Stage:Defense Evasion
message: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to encrypt disks.
message: An instance of $parent_process_name$ spawning $process_name$ was identified
on endpoint $dest$ by user $user$ attempting to encrypt disks.
observable:
- name: user
type: User
@@ -69,4 +80,4 @@ tags:
type: Process
role:
- Child Process
automated_detection_testing: passed