Detection rules › Sigma

InstallerFileTakeOver LPE CVE-2021-41379 File Create Event

Status
test
Severity
critical
Log source
product windows, category file_event
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects signs of the exploitation of LPE CVE-2021-41379 that include an msiexec process that creates an elevation_service.exe file

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1068 Exploitation for Privilege Escalation

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: InstallerFileTakeOver LPE CVE-2021-41379 File Create Event
id: 3be82d5d-09fe-4d6a-a275-0d40d234d324
status: test
description: Detects signs of the exploitation of LPE CVE-2021-41379 that include an msiexec process that creates an elevation_service.exe file
references:
    - https://web.archive.org/web/20220421061949/https://github.com/klinix5/InstallerFileTakeOver
    - https://www.zerodayinitiative.com/advisories/ZDI-21-1308/
author: Florian Roth (Nextron Systems)
date: 2021-11-22
modified: 2022-12-25
tags:
    - attack.privilege-escalation
    - attack.t1068
    - detection.emerging-threats
logsource:
    category: file_event
    product: windows
detection:
    selection:
        Image|endswith: '\msiexec.exe'
        TargetFilename|startswith: 'C:\Program Files (x86)\Microsoft\Edge\Application'
        TargetFilename|endswith: '\elevation_service.exe'
    condition: selection
falsepositives:
    - Unknown
    - Possibly some Microsoft Edge upgrades
level: critical

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\msiexec.exe'
    TargetFilename|startswith: 'C:\Program Files (x86)\Microsoft\Edge\Application'
    TargetFilename|endswith: '\elevation_service.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
Imageends_with
  • \msiexec.exe corpus 21 (sigma 21)
TargetFilenameends_with
  • \elevation_service.exe
TargetFilenamestarts_with
  • C:\Program Files (x86)\Microsoft\Edge\Application