Suspicious Print Spooler File Deletion

Elastic Stack Serverless Security

Detects deletion of print driver files by an unusual process. This may indicate a clean up attempt post successful privilege escalation via Print Spooler service related vulnerabilities.

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:

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34527
• https://github.com/afwu/PrintNightmare

Tags:

• Elastic
• Host
• Windows
• Threat Detection
• Privilege Escalation

Version: 2

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.

file where event.type : "deletion" and
 not process.name : ("spoolsv.exe", "dllhost.exe", "explorer.exe") and
 file.path : "?:\\Windows\\System32\\spool\\drivers\\x64\\3\\*.dll"

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Privilege Escalation
  • ID: TA0004
  • Reference URL: https://attack.mitre.org/tactics/TA0004/

• Technique:

  • Name: Exploitation for Privilege Escalation
  • ID: T1068
  • Reference URL: https://attack.mitre.org/techniques/T1068/