Persistence via Update Orchestrator Service Hijack

Identifies potential hijacking of the Microsoft Update Orchestrator Service to establish persistence with an integrity level of SYSTEM.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

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://github.com/irsl/CVE-2020-1313

Tags:

Elastic
Host
Windows
Threat Detection
Persistence
CVE-2020-1313

Version: 8

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

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## Setup

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

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process where event.type == "start" and
  process.parent.executable : "C:\\Windows\\System32\\svchost.exe" and
  process.parent.args : "UsoSvc" and
  not process.executable :
          ("?:\\ProgramData\\Microsoft\\Windows\\UUS\\Packages\\*\\amd64\\MoUsoCoreWorker.exe",
          "?:\\Windows\\System32\\UsoClient.exe",
          "?:\\Windows\\System32\\MusNotification.exe",
          "?:\\Windows\\System32\\MusNotificationUx.exe",
          "?:\\Windows\\System32\\MusNotifyIcon.exe",
          "?:\\Windows\\System32\\WerFault.exe",
          "?:\\Windows\\System32\\WerMgr.exe",
          "?:\\Windows\\UUS\\amd64\\MoUsoCoreWorker.exe",
          "?:\\Windows\\System32\\MoUsoCoreWorker.exe",
          "?:\\Windows\\UUS\\amd64\\UsoCoreWorker.exe",
          "?:\\Windows\\System32\\UsoCoreWorker.exe",
          "?:\\Program Files\\Common Files\\microsoft shared\\ClickToRun\\OfficeC2RClient.exe")

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
Technique:
- Name: Create or Modify System Process
- ID: T1543
- Reference URL: https://attack.mitre.org/techniques/T1543/
Sub-technique:
- Name: Windows Service
- ID: T1543.003
- Reference URL: https://attack.mitre.org/techniques/T1543/003/

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