Windows Sysmon Application Popup Crash (Event ID 26)

Flags Application Popup events reporting sysmon64.exe/sysmon.exe “Application Error” (Event ID 26).

FreeReviewedSigma · High · v2

Product: windows
Service: system
Author: Tim Shelton (SigmaHQ), DRL 1.1
Published: 2022-04-26
Updated: 2026-07-31

ATT&CK techniques

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule matches Windows System service events where the “Application Popup” provider reports an application error for sysmon64.exe or sysmon.exe with Event ID 26. An attacker or user impact scenario may attempt to disrupt monitoring by causing Sysmon to crash, reducing visibility. The detection relies on System log telemetry containing the Application Popup provider name, event ID, and the specific sysmon application error captions.

Reporting behind it

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Windows Sysmon Application Popup Crash (Event ID 26)

Pivot detection · T1685 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-sysmon-application-error-popups-application-popup-event-id-26-4d7f1827

title: Windows Sysmon Application Popup Crash (Event ID 26)
id: aa68b28d-5ea3-4adb-b9a9-21f62d3547a2
status: test
description: This rule matches Windows System service events where the “Application Popup” provider reports an application error for sysmon64.exe or sysmon.exe with Event ID 26. An attacker or user impact scenario may attempt to disrupt monitoring by causing Sysmon to crash, reducing visibility. The detection relies on System log telemetry containing the Application Popup provider name, event ID, and the specific sysmon application error captions.
references:
  - https://github.com/nasbench/EVTX-ETW-Resources/blob/f1b010ce0ee1b71e3024180de1a3e67f99701fe4/ETWProvidersManifests/Windows10/1803/W10_1803_Pro_19700101_17134.1/WEPExplorer/Application%20Popup.xml#L36
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/system/application_popup/win_system_application_sysmon_crash.yml
author: Tim Shelton, Huntrule Team
date: 2022-04-26
modified: 2024-01-17
tags:
  - attack.defense-impairment
  - attack.t1685
logsource:
  product: windows
  service: system
detection:
  selection:
    Provider_Name: Application Popup
    EventID: 26
    Caption:
      - sysmon64.exe - Application Error
      - sysmon.exe - Application Error
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 4d7f1827-1637-4def-8d8a-fd254f9454df
    type: derived

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