Detection: Known Services Killed by Ransomware

Description

The following analytic detects the suspicious termination of known services commonly targeted by ransomware before file encryption. It leverages Windows System Event Logs (EventCode 7036) to identify when critical services such as Volume Shadow Copy, backup, and antivirus services are stopped. This activity is significant because ransomware often disables these services to avoid errors and ensure successful file encryption. If confirmed malicious, this behavior could lead to widespread data encryption, rendering files inaccessible and potentially causing significant operational disruption and data loss.

1`wineventlog_system` EventCode=7036 param1 IN ("*Volume Shadow Copy*","*VSS*", "*backup*", "*sophos*", "*sql*", "*memtas*", "*mepocs*", "*veeam*", "*svc$*", "DefWatch", "ccEvtMgr", "ccSetMgr", "SavRoam", "RTVscan", "QBFCService", "QBIDPService", "Intuit.QuickBooks.FCS", "QBCFMonitorService" "YooBackup", "YooIT", "*Veeam*", "PDVFSService", "BackupExecVSSProvider", "BackupExecAgentAccelerator", "BackupExec*", "WdBoot", "WdFilter", "WdNisDrv", "WdNisSvc", "WinDefend", "wscsvc", "Sense", "sppsvc", "SecurityHealthService") param2="stopped" 
2| stats count min(_time) as firstTime max(_time) as lastTime by EventCode param1 dest 
3| `security_content_ctime(lastTime)` 
4| `security_content_ctime(firstTime)` 
5| `known_services_killed_by_ransomware_filter`

Data Source

Name Platform Sourcetype Source Supported App
Windows Event Log System 7036 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:System' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
known_services_killed_by_ransomware_filter search *
known_services_killed_by_ransomware_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1490 Inhibit System Recovery Impact
KillChainPhase.ACTIONS_ON_OBJECTIVES
NistCategory.DE_CM
Cis18Value.CIS_10
Wizard Spider

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you need to be ingesting logs with the 7036 EventCode ScManager in System audit Logs from your endpoints.

Known False Positives

Admin activities or installing related updates may do a sudden stop to list of services we monitor.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Known services $param1$ terminated by a potential ransomware on $dest$ 72 90 80
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Passing N/A N/A N/A
Unit Passing Dataset XmlWinEventLog:System XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:System XmlWinEventLog

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range


Source: GitHub | Version: 4