Detection rules › Sigma
Potential Fake Instance Of Hxtsr.EXE Executed
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
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1036 Masquerading |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
title: Potential Fake Instance Of Hxtsr.EXE Executed
id: 4e762605-34a8-406d-b72e-c1a089313320
status: test
description: |
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
references:
- Internal Research
author: Sreeman
date: 2020-04-17
modified: 2024-02-08
tags:
- attack.stealth
- attack.t1036
logsource:
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_*
falsepositives:
- Unknown
level: medium
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_*Stage 1: selection
selection:
Image|endswith: '\hxtsr.exe'
Stage 2: not filter_main_hxtsr
filter_main_hxtsr:
Image|contains: ':\program files\windowsapps\microsoft.windowscommunicationsapps_'
Image|endswith: '\hxtsr.exe'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
Image | ends_with | \hxtsr.exe |
Image | match | :\program files\windowsapps\microsoft.windowscommunicationsapps_ |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Image | ends_with |
|