Registry Persistence via AppCert DLL

Elastic Stack Serverless Security

Detects attempts to maintain persistence by creating registry keys using AppCert DLLs. AppCert DLLs are loaded by every process using the common API functions to create processes.

Rule type: eql

Rule indices:

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

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

• Elastic
• Host
• Windows
• Threat Detection
• Persistence

Version: 5

Rule authors:

• Elastic

Rule license: Elastic License v2

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.

registry where
/* uncomment once stable length(bytes_written_string) > 0 and */
  registry.path : "HKLM\\SYSTEM\\*ControlSet*\\Control\\Session Manager\\AppCertDLLs\\*"

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Persistence
  • ID: TA0003
  • Reference URL: https://attack.mitre.org/tactics/TA0003/

• Technique:

  • Name: Event Triggered Execution
  • ID: T1546
  • Reference URL: https://attack.mitre.org/techniques/T1546/

• Sub-technique:

  • Name: AppCert DLLs
  • ID: T1546.009
  • Reference URL: https://attack.mitre.org/techniques/T1546/009/