Detection rules › Sigma
Potential CVE-2021-41379 Exploitation Attempt
Detects potential exploitation attempts of CVE-2021-41379 (InstallerFileTakeOver), a local privilege escalation (LPE) vulnerability where the attacker spawns a "cmd.exe" process as a child of Microsoft Edge elevation service "elevation_service" with "LOCAL_SYSTEM" rights
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Privilege Escalation | T1068 Exploitation for Privilege Escalation |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
title: Potential CVE-2021-41379 Exploitation Attempt
id: af8bbce4-f751-46b4-8d91-82a33a736f61
status: test
description: Detects potential exploitation attempts of CVE-2021-41379 (InstallerFileTakeOver), a local privilege escalation (LPE) vulnerability where the attacker spawns a "cmd.exe" process as a child of Microsoft Edge elevation service "elevation_service" with "LOCAL_SYSTEM" rights
references:
- https://web.archive.org/web/20220421061949/https://github.com/klinix5/InstallerFileTakeOver
- https://www.bleepingcomputer.com/news/microsoft/new-windows-zero-day-with-public-exploit-lets-you-become-an-admin/
- https://www.zerodayinitiative.com/advisories/ZDI-21-1308/
- https://www.logpoint.com/en/blog/detecting-privilege-escalation-zero-day-cve-2021-41379/
author: Florian Roth (Nextron Systems)
date: 2021-11-22
modified: 2024-12-01
tags:
- attack.privilege-escalation
- attack.t1068
- cve.2021-41379
- detection.emerging-threats
logsource:
category: process_creation
product: windows
detection:
selection_img:
- Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
- '\pwsh.exe'
- OriginalFileName:
- 'Cmd.Exe'
- 'PowerShell.EXE'
- 'pwsh.dll'
selection_parent:
ParentImage|endswith: '\elevation_service.exe'
IntegrityLevel:
- 'System'
- 'S-1-16-16384' # System
condition: all of selection_*
falsepositives:
- Unknown
level: critical
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_img
selection_img:
- Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
- '\pwsh.exe'
- OriginalFileName:
- 'Cmd.Exe'
- 'PowerShell.EXE'
- 'pwsh.dll'
Stage 2: selection_parent
selection_parent:
ParentImage|endswith: '\elevation_service.exe'
IntegrityLevel:
- 'System'
- 'S-1-16-16384'
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 |
|
IntegrityLevel | eq |
|
OriginalFileName | eq |
|
ParentImage | ends_with |
|