Detection rules › Sigma
Uncommon Child Process Of Appvlp.EXE
Detects uncommon child processes of Appvlp.EXE Appvlp or the Application Virtualization Utility is included with Microsoft Office. Attackers are able to abuse "AppVLP" to execute shell commands. Normally, this binary is used for Application Virtualization, but it can also be abused to circumvent the ASR file path rule folder or to mark a file as a system file.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1218 System Binary Proxy Execution |
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: Uncommon Child Process Of Appvlp.EXE
id: 9c7e131a-0f2c-4ae0-9d43-b04f4e266d43
status: test
description: |
Detects uncommon child processes of Appvlp.EXE
Appvlp or the Application Virtualization Utility is included with Microsoft Office. Attackers are able to abuse "AppVLP" to execute shell commands.
Normally, this binary is used for Application Virtualization, but it can also be abused to circumvent the ASR file path rule folder
or to mark a file as a system file.
references:
- https://lolbas-project.github.io/lolbas/OtherMSBinaries/Appvlp/
author: Sreeman
date: 2020-03-13
modified: 2023-11-09
tags:
- attack.stealth
- attack.t1218
- attack.execution
logsource:
category: process_creation
product: windows
detection:
selection:
ParentImage|endswith: '\appvlp.exe'
# Note: Filters based on data from EchoTrail: https://www.echotrail.io/insights/search/appvlp.exe/
filter_main_generic:
Image|endswith:
- ':\Windows\SysWOW64\rundll32.exe'
- ':\Windows\System32\rundll32.exe'
filter_optional_office_msoasb:
Image|contains: ':\Program Files\Microsoft Office'
Image|endswith: '\msoasb.exe'
filter_optional_office_skype:
Image|contains|all:
- ':\Program Files\Microsoft Office'
- '\SkypeSrv\'
Image|endswith: '\SKYPESERVER.EXE'
filter_optional_office_msouc:
Image|contains: ':\Program Files\Microsoft Office'
Image|endswith: '\MSOUC.EXE'
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
- Unknown
level: medium
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_* and not 1 of filter_optional_*Stage 1: selection
selection:
ParentImage|endswith: '\appvlp.exe'
Stage 2: not filter_main_generic
filter_main_generic:
Image|endswith:
- ':\Windows\SysWOW64\rundll32.exe'
- ':\Windows\System32\rundll32.exe'
Stage 3: not filter_optional_*
filter_optional_office_msoasb:
Image|contains: ':\Program Files\Microsoft Office'
Image|endswith: '\msoasb.exe'
filter_optional_office_skype:
Image|contains|all:
- ':\Program Files\Microsoft Office'
- '\SkypeSrv\'
Image|endswith: '\SKYPESERVER.EXE'
filter_optional_office_msouc:
Image|contains: ':\Program Files\Microsoft Office'
Image|endswith: '\MSOUC.EXE'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
Image | ends_with | :\Windows\SysWOW64\rundll32.exe |
Image | ends_with | :\Windows\System32\rundll32.exe |
Image | ends_with | \MSOUC.EXE |
Image | match | :\Program Files\Microsoft Office |
Image | ends_with | \SKYPESERVER.EXE |
Image | match | :\Program Files\Microsoft Office |
Image | match | \SkypeSrv\ |
Image | ends_with | \msoasb.exe |
Image | match | :\Program Files\Microsoft Office |
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 |
|---|---|---|
ParentImage | ends_with |
|