Important Scheduled Task Deleted or Disabled

Status: test
Severity: high
Log source: product windows, service taskscheduler
Author: frack113
Source: github.com/SigmaHQ/sigma

Detects when adversaries try to stop system services or processes by deleting or disabling their respective scheduled tasks in order to conduct data destructive activities

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1489` Service Stop

Event coverage

Provider	Event	Title
TaskScheduler	Event ID 141	User "TaskName" deleted Task Scheduler task "Name".
TaskScheduler	Event ID 142	User "TaskName" disabled Task Scheduler task "Name".

Rule body yaml

title: Important Scheduled Task Deleted or Disabled
id: 9e3cb244-bdb8-4632-8c90-6079c8f4f16d
related:
    - id: dbc1f800-0fe0-4bc0-9c66-292c2abe3f78 # ProcCreation schtasks delete
      type: similar
    - id: 7595ba94-cf3b-4471-aa03-4f6baa9e5fad # Security-Audting Eventlog
      type: similar
    - id: 9ac94dc8-9042-493c-ba45-3b5e7c86b980 # ProcCreation schtasks disable
      type: similar
status: test
description: |
    Detects when adversaries try to stop system services or processes by deleting or disabling their respective scheduled tasks in order to conduct data destructive activities
references:
    - https://www.socinvestigation.com/most-common-windows-event-ids-to-hunt-mind-map/
author: frack113
date: 2023-01-13
modified: 2026-03-11
tags:
    - attack.impact
    - attack.t1489
logsource:
    product: windows
    service: taskscheduler
    definition: 'Requirements: The "Microsoft-Windows-TaskScheduler/Operational" is disabled by default and needs to be enabled in order for this detection to trigger'
detection:
    selection:
        EventID:
            - 141 # Task Deleted
            - 142 # Task Disabled
        TaskName|contains:
            - '\Windows\SystemRestore\SR'
            - '\Windows\Windows Defender\'
            - '\Windows\BitLocker'
            - '\Windows\WindowsBackup\'
            - '\Windows\WindowsUpdate\'
            - '\Windows\UpdateOrchestrator\'
            - '\Windows\ExploitGuard'
    filter_main_user:
        UserName|contains:
            - 'AUTHORI'
            - 'AUTORI'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/builtin/taskscheduler/win_taskscheduler_susp_schtasks_delete_or_disable/info.yml
simulation:
    - type: atomic-red-team
      name: Windows - Disable the SR scheduled task
      technique: T1490
      atomic_guid: 1c68c68d-83a4-4981-974e-8993055fa034

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    EventID:
        - 141
        - 142
    TaskName|contains:
        - '\Windows\SystemRestore\SR'
        - '\Windows\Windows Defender\'
        - '\Windows\BitLocker'
        - '\Windows\WindowsBackup\'
        - '\Windows\WindowsUpdate\'
        - '\Windows\UpdateOrchestrator\'
        - '\Windows\ExploitGuard'

Stage 2: `not filter_main_user`

filter_main_user:
    UserName|contains:
        - 'AUTHORI'
        - 'AUTORI'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`UserName`	match	`AUTHORI`
`UserName`	match	`AUTORI`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`TaskName`	match	`\Windows\BitLocker` corpus 2 (sigma 2) `\Windows\ExploitGuard` corpus 2 (sigma 2) `\Windows\SystemRestore\SR` corpus 2 (sigma 2) `\Windows\UpdateOrchestrator\` `\Windows\Windows Defender\` corpus 2 (sigma 2) `\Windows\WindowsBackup\` corpus 2 (sigma 2) `\Windows\WindowsUpdate\` corpus 2 (sigma 2)

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Important Scheduled Task Deleted or Disabled

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_user`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Important Scheduled Task Deleted or Disabled

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter_main_user

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_user`