Windows: Process Execution of Suspicious hxtsr.exe (Outside WindowsApps)

Alerts when hxtsr.exe runs from a non-expected WindowsApps Microsoft.WindowsCommunicationsApps location.

FreeReviewedSigma · Medium · v2

Product: windows
Category: process_creation
Author: Sreeman (SigmaHQ), DRL 1.1
Published: 2020-04-17
Updated: 2026-07-31

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1036Masquerading
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process executions where the image path ends with \hxtsr.exe, but the executable is not found in the expected WindowsApps Microsoft.WindowsCommunicationsApps subfolder. Attackers may use a filename masquerade to appear legitimate by planting or executing a fake hxtsr.exe elsewhere on the system. The detection relies on process creation telemetry including the full Image path and uses string matching on the executable name and location.

Reporting behind it

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Windows: Process Execution of Suspicious hxtsr.exe (Outside WindowsApps)

Pivot detection · T1036 · 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-executed-hxtsr-exe-from-outside-microsoft-windowscommunicationsapps-wind-4e762605

title: "Windows: Process Execution of Suspicious hxtsr.exe (Outside WindowsApps)"
id: c0a956bc-0d37-477e-9471-3a0a2a24571a
status: test
description: This rule flags process executions where the image path ends with \hxtsr.exe, but the executable is not found in the expected WindowsApps Microsoft.WindowsCommunicationsApps subfolder. Attackers may use a filename masquerade to appear legitimate by planting or executing a fake hxtsr.exe elsewhere on the system. The detection relies on process creation telemetry including the full Image path and uses string matching on the executable name and location.
references:
  - Internal Research
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_hxtsr_masquerading.yml
author: Sreeman, Huntrule Team
date: 2020-04-17
modified: 2024-02-08
tags:
  - attack.stealth
  - attack.t1036
logsource:
  product: windows
  category: process_creation
detection:
  selection:
    Image|endswith: \hxtsr.exe
  filter_main_hxtsr:
    Image|contains: :\program files\windowsapps\microsoft.windowscommunicationsapps_
    Image|endswith: \hxtsr.exe
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 4e762605-34a8-406d-b72e-c1a089313320
    type: derived

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