Sigma rule: Potential Fake Instance Of Hxtsr.EXE Executed

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-1c20e779ba88, updated 2024-02-08T00:00:00.000Z.

Rule

Title
Potential Fake Instance Of Hxtsr.EXE Executed
Status
test
Level
medium
Author
Sreeman
Date
2020-04-17
Modified
2024-02-08
File
rules/windows/process_creation/proc_creation_win_hxtsr_masquerading.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

HxTsr.exe is a Microsoft compressed executable file called Microsoft Outlook Communications.
HxTsr.exe is part of Outlook apps, because it resides in a hidden "WindowsApps" subfolder of "C:\Program Files".
Any instances of hxtsr.exe not in this folder may be malware camouflaging itself as HxTsr.exe

Log source

product
windows
category
process_creation

Detection

# TODO: Link this to the more generic system process rule
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_*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.stealth
  • attack.t1036

MITRE ATT&CK ids this rule names

References

  • Internal Research

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_hxtsr_masquerading.yml

Sources and licences

  • SigmaHQ

    "Potential Fake Instance Of Hxtsr.EXE Executed" by Sreeman (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_hxtsr_masquerading.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Potential Fake Instance Of Hxtsr.EXE Executed",
entity page, dataset version ref-1c20e779ba88, updated 2024-02-08T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/4e762605-34a8-406d-b72e-c1a089313320 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 4e762605-34a8-406d-b72e-c1a089313320, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.