Stopping multiple processes using taskkill

Status: available
Severity: medium
Time window: 2m
Group by: DeviceId, DeviceName
Source: github.com/Azure/Azure-Sentinel

This query checks for attempts to stop at least 10 separate processes using the taskkill.exe utility. This is a common technique used by ransomware to stop security products and other processes.

MITRE ATT&CK coverage

Tactic	Techniques
Defense Impairment	`T1685` Disable or Modify Tools

Telemetry coverage

Platform	Record / event type
Microsoft Defender for Endpoint	`DeviceProcessEvents` action `any`: Process activity

Rule body

id: 4dd31bd5-11a3-4b9c-a7c5-4927ab4f2a77
name: Stopping multiple processes using taskkill
description: |
  This query checks for attempts to stop at least 10 separate processes using the taskkill.exe utility. This is a common technique used by ransomware to stop security products and other processes.
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceProcessEvents
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1562
query: |
  // Find attempts to stop processes using taskkill.exe
  DeviceProcessEvents
  | where FileName =~ "taskkill.exe" 
  | summarize taskKillCount = dcount(ProcessCommandLine), TaskKillList = make_set(ProcessCommandLine, 10000) by DeviceId, DeviceName, bin(TimeGenerated, 2m)
  | where taskKillCount > 10
  | extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
  | extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")
entityMappings:  
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: DeviceName
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: `source`

DeviceProcessEvents

Stage 2: `where`

| where FileName =~ "taskkill.exe"

Stage 3: `summarize`

| summarize taskKillCount = dcount(ProcessCommandLine), TaskKillList = make_set(ProcessCommandLine, 10000) by DeviceId, DeviceName, bin(TimeGenerated, 2m)

Stage 4: `where`

| where taskKillCount > 10

Stage 5: `extend`

| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)

HostName =

ifDeviceName has "."substring(DeviceName, 0, indexof(DeviceName, '.'))

elseDeviceName

Stage 6: `extend`

| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")

DnsDomain =

ifDeviceName has "."substring(DeviceName, (indexof(DeviceName, '.') + 1))

else""

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`FileName`	eq	`taskkill.exe`	`field:"file_name" kind:eq value:"taskkill.exe"`
`taskKillCount`	gt	`10`	`field:"taskKillCount" kind:gt value:"10"`

Output fields

These fields are emitted when the rule matches.

Field	Source
`DeviceId`	`summarize`
`DeviceName`	`summarize`
`TaskKillList`	`summarize`
`taskKillCount`	`summarize`
`HostName`	`extend`
`DnsDomain`	`extend`

Stopping multiple processes using taskkill

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: summarize

Stage 4: where

Stage 5: extend

Stage 6: extend