Detection rules › Sigma

Malicious PE Execution by Microsoft Visual Studio Debugger

Status
test
Severity
medium
Log source
product windows, category process_creation
Author
Agro (@agro_sev), Ensar Şamil (@sblmsrsn), oscd.community
Source
github.com/SigmaHQ/sigma

There is an option for a MS VS Just-In-Time Debugger "vsjitdebugger.exe" to launch specified executable and attach a debugger. This option may be used adversaries to execute malicious code by signed verified binary. The debugger is installed alongside with Microsoft Visual Studio package.

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: Malicious PE Execution by Microsoft Visual Studio Debugger
id: 15c7904e-6ad1-4a45-9b46-5fb25df37fd2
status: test
description: |
  There is an option for a MS VS Just-In-Time Debugger "vsjitdebugger.exe" to launch specified executable and attach a debugger.
  This option may be used adversaries to execute malicious code by signed verified binary.
  The debugger is installed alongside with Microsoft Visual Studio package.
references:
    - https://twitter.com/pabraeken/status/990758590020452353
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Vsjitdebugger/
    - https://learn.microsoft.com/en-us/visualstudio/debugger/debug-using-the-just-in-time-debugger?view=vs-2019
author: Agro (@agro_sev), Ensar Şamil (@sblmsrsn), oscd.community
date: 2020-10-14
modified: 2022-10-09
tags:
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\vsjitdebugger.exe'
    reduction1:
        Image|endswith: '\vsimmersiveactivatehelper*.exe'
    reduction2:
        Image|endswith: '\devenv.exe'
    condition: selection and not (reduction1 or reduction2)
falsepositives:
    - The process spawned by vsjitdebugger.exe is uncommon.
level: medium

Stages and Predicates

Stage 0: condition

selection and not (reduction1 or reduction2)

Stage 1: selection

selection:
    ParentImage|endswith: '\vsjitdebugger.exe'

Stage 2: not reduction1

reduction1:
    Image|endswith: '\vsimmersiveactivatehelper*.exe'

Stage 3: not reduction2

reduction2:
    Image|endswith: '\devenv.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imageends_with\vsimmersiveactivatehelper*.exe
Imageends_with\devenv.exe

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.

FieldKindValues
ParentImageends_with
  • \vsjitdebugger.exe