Detection: Known Services Killed by Ransomware

Updated Date: 2024-08-16 ID: 3070f8e0-c528-11eb-b2a0-acde48001122 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

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.

Search

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	`'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