Detection rules › Sigma

Potentially Suspicious Electron Application CommandLine

Status
test
Severity
medium
Log source
product windows, category process_creation
Author
frack113, Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects potentially suspicious CommandLine of electron apps (teams, discord, slack, etc.). This could be a sign of abuse to proxy execution through a signed binary.

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Potentially Suspicious Electron Application CommandLine
id: 378a05d8-963c-46c9-bcce-13c7657eac99
related:
    - id: f26eb764-fd89-464b-85e2-dc4a8e6e77b8
      type: similar
status: test
description: Detects potentially suspicious CommandLine of electron apps (teams, discord, slack, etc.). This could be a sign of abuse to proxy execution through a signed binary.
references:
    - https://positive.security/blog/ms-officecmd-rce
    - https://lolbas-project.github.io/lolbas/Binaries/Teams/
    - https://lolbas-project.github.io/lolbas/Binaries/Msedge/
    - https://lolbas-project.github.io/lolbas/Binaries/msedgewebview2/
    - https://medium.com/@MalFuzzer/one-electron-to-rule-them-all-dc2e9b263daf
    - https://chromium.googlesource.com/chromium/chromium/+/master/content/public/common/content_switches.cc
author: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2023-09-05
modified: 2023-11-09
tags:
    - attack.execution
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              # Add more electron based app to the list
              - '\chrome.exe'
              - '\code.exe'
              - '\discord.exe'
              - '\GitHubDesktop.exe'
              - '\keybase.exe'
              - '\msedge_proxy.exe'
              - '\msedge.exe'
              - '\msedgewebview2.exe'
              - '\msteams.exe'
              - '\slack.exe'
              - '\Teams.exe'
        - OriginalFileName:
              # Add more electron based app to the list
              - 'chrome.exe'
              - 'code.exe'
              - 'discord.exe'
              - 'GitHubDesktop.exe'
              - 'keybase.exe'
              - 'msedge_proxy.exe'
              - 'msedge.exe'
              - 'msedgewebview2.exe'
              - 'msteams.exe'
              - 'slack.exe'
              - 'Teams.exe'
    selection_cli:
        CommandLine|contains:
            - '--browser-subprocess-path'
            - '--gpu-launcher'
            - '--renderer-cmd-prefix'
            - '--utility-cmd-prefix'
    condition: all of selection_*
falsepositives:
    - Legitimate usage for debugging purposes
# Increase the level once FP rate is known better (see status)
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith:
          - '\chrome.exe'
          - '\code.exe'
          - '\discord.exe'
          - '\GitHubDesktop.exe'
          - '\keybase.exe'
          - '\msedge_proxy.exe'
          - '\msedge.exe'
          - '\msedgewebview2.exe'
          - '\msteams.exe'
          - '\slack.exe'
          - '\Teams.exe'
    - OriginalFileName:
          - 'chrome.exe'
          - 'code.exe'
          - 'discord.exe'
          - 'GitHubDesktop.exe'
          - 'keybase.exe'
          - 'msedge_proxy.exe'
          - 'msedge.exe'
          - 'msedgewebview2.exe'
          - 'msteams.exe'
          - 'slack.exe'
          - 'Teams.exe'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains:
        - '--browser-subprocess-path'
        - '--gpu-launcher'
        - '--renderer-cmd-prefix'
        - '--utility-cmd-prefix'

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
CommandLinematch
  • --browser-subprocess-path
  • --gpu-launcher
  • --renderer-cmd-prefix
  • --utility-cmd-prefix
Imageends_with
  • \GitHubDesktop.exe
  • \Teams.exe corpus 2 (sigma 2)
  • \chrome.exe corpus 13 (sigma 13)
  • \code.exe
  • \discord.exe corpus 2 (sigma 2)
  • \keybase.exe corpus 2 (sigma 2)
  • \msedge.exe corpus 14 (sigma 14)
  • \msedge_proxy.exe corpus 2 (sigma 2)
  • \msedgewebview2.exe corpus 3 (sigma 3)
  • \msteams.exe corpus 2 (sigma 2)
  • \slack.exe corpus 2 (sigma 2)
OriginalFileNameeq
  • GitHubDesktop.exe
  • Teams.exe corpus 2 (sigma 2)
  • chrome.exe
  • code.exe
  • discord.exe
  • keybase.exe
  • msedge.exe
  • msedge_proxy.exe corpus 2 (sigma 2)
  • msedgewebview2.exe
  • msteams.exe corpus 2 (sigma 2)
  • slack.exe