Privilege Escalation via Windir Environment Variable

Identifies a privilege escalation attempt via a rogue Windows directory (Windir) environment variable. This is a known primitive that is often combined with other vulnerabilities to elevate privileges.

Rule type: eql

Rule indices:

logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://www.tiraniddo.dev/2017/05/exploiting-environment-variables-in.html

Tags:

Elastic
Host
Windows
Threat Detection
Privilege Escalation

Version: 101

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

registry where registry.path : ("HKEY_USERS\\*\\Environment\\windir", "HKEY_USERS\\*\\Environment\\systemroot") and
 not registry.data.strings : ("C:\\windows", "%SystemRoot%")

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Privilege Escalation
- ID: TA0004
- Reference URL: https://attack.mitre.org/tactics/TA0004/
Technique:
- Name: Hijack Execution Flow
- ID: T1574
- Reference URL: https://attack.mitre.org/techniques/T1574/
Sub-technique:
- Name: Path Interception by PATH Environment Variable
- ID: T1574.007
- Reference URL: https://attack.mitre.org/techniques/T1574/007/

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