Uninstall Sysinternals Sysmon

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

Detects the removal of Sysmon, which could be a potential attempt at defense evasion

Known false positives

Legitimate administrators might use this command to remove Sysmon for debugging purposes

MITRE ATT&CK coverage

Tactic	Techniques
Defense Impairment	`T1685` Disable or Modify Tools

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Uninstall Sysinternals Sysmon
id: 6a5f68d1-c4b5-46b9-94ee-5324892ea939
status: test
description: Detects the removal of Sysmon, which could be a potential attempt at defense evasion
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1562.001/T1562.001.md#atomic-test-11---uninstall-sysmon
author: frack113
date: 2022-01-12
modified: 2026-06-29
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    category: process_creation
    product: windows
detection:
    selection_pe:
        - Image|endswith:
              - \Sysmon64.exe
              - \Sysmon64a.exe
              - \Sysmon.exe
        - Description: 'System activity monitor'
    selection_cli:
        CommandLine|contains|windash: '-u'
    condition: all of selection_*
falsepositives:
    - Legitimate administrators might use this command to remove Sysmon for debugging purposes
level: high

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_pe`

selection_pe:
    - Image|endswith:
          - \Sysmon64.exe
          - \Sysmon64a.exe
          - \Sysmon.exe
    - Description: 'System activity monitor'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains|windash: '-u'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-u` transforms: `windash` corpus 6 (sigma 5, splunk 1)	`field:"CommandLine" kind:match value:"-u"`
`Description`	eq	`System activity monitor` corpus 2 (sigma 2)	`field:"Description" kind:eq value:"System activity monitor"`
`Image`	ends_with	`\Sysmon.exe` corpus 3 (sigma 3) `\Sysmon64.exe` corpus 3 (sigma 3) `\Sysmon64a.exe` corpus 3 (sigma 3)	`field:"Image" kind:ends_with`

Uninstall Sysinternals Sysmon

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_pe

Stage 2: selection_cli

Indicators

Stage 0: `condition`

Stage 1: `selection_pe`

Stage 2: `selection_cli`