Windows Defender windefend Event 1119 flags RedSun TieringEngineService.exe EICAR test file

Alerts on WinDefend 1119 remediation failures involving TieringEngineService.exe marked with EICAR content or triggered by RedSun.exe.

FreeReviewedSigma · Critical · v5

Product: windows
Service: windefend
Author: Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2026-04-17
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Priv Esc → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
- T1055Process Injection
Defense Evasion
- T1036.005Match Legitimate Resource Name or Location
- T1055Process Injection
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows Defender real-time protection events (EventID 1119) where remediation fails for TieringEngineService.exe staged in a temporary RS-{GUID} directory with an EICAR test filename indicator, or when RedSun.exe is present. Attackers may use this kind of staging and scanning-race behavior to interfere with or bypass security controls and pivot into execution. The detection relies on windefend telemetry capturing EventID 1119 along with the file path, ThreatName ending in EICAR_Test_File, and/or process name ending in RedSun.exe.

Reporting behind it

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Windows Defender windefend Event 1119 flags RedSun TieringEngineService.exe EICAR test file

Pivot detection · T1036.005 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
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-defender-windefend-flags-tieringengineservice-exe-eicar-test-staging-by--a7c3e5f2

title: Windows Defender windefend Event 1119 flags RedSun TieringEngineService.exe EICAR test file
id: 5b9df56f-e5d3-41ff-a7a6-5b8b45bbfb09
status: experimental
description: This rule flags Windows Defender real-time protection events (EventID 1119) where remediation fails for TieringEngineService.exe staged in a temporary RS-{GUID} directory with an EICAR test filename indicator, or when RedSun.exe is present. Attackers may use this kind of staging and scanning-race behavior to interfere with or bypass security controls and pivot into execution. The detection relies on windefend telemetry capturing EventID 1119 along with the file path, ThreatName ending in EICAR_Test_File, and/or process name ending in RedSun.exe.
references:
  - https://github.com/Nightmare-Eclipse/RedSun/blob/7456cc8cf066f5e5fc6cdf7d3272a466ebd6b2f6/RedSun.cpp#L605
  - https://deadeclipse666.blogspot.com/2026/04/public-disclosure-response-for-cve-2026.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2026/Exploits/RedSun/win_defender_exploit_redsun_tiering_engine_detected_as_eicar.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
date: 2026-04-17
tags:
  - attack.stealth
  - attack.defense-impairment
  - attack.t1036.005
  - attack.t1685
  - attack.privilege-escalation
  - attack.t1055
  - detection.emerging-threats
logsource:
  product: windows
  service: windefend
detection:
  selection_eid:
    EventID: 1119
    SourceName: Real-Time Protection
  selection_susp_path:
    Path|endswith: \TieringEngineService.exe
    ThreatName|endswith: EICAR_Test_File
  selection_susp_process:
    ProcessName|endswith: \RedSun.exe
  condition: selection_eid and 1 of selection_susp_*
falsepositives:
  - Unlikely
level: critical
regression_tests_path: regression_data/rules-emerging-threats/2026/Exploits/RedSun/win_defender_exploit_redsun_tiering_engine_detected_as_eicar/info.yml
license: DRL-1.1
related:
  - id: a7c3e5f2-8b1d-4e9a-b6c2-3d7f5e8a9b4c
    type: derived

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