Suspicious PrintSpooler SPL File Created

Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service including CVE-2020-1048 and CVE-2020-1337. .

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://safebreach.com/Post/How-we-bypassed-CVE-2020-1048-Patch-and-got-CVE-2020-1337

Tags:

Elastic
Host
Windows
Threat Detection
Privilege Escalation

Version: 8

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

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## Threat intel

Refer to CVEs, CVE-2020-1048 and CVE-2020-1337 for further information on the vulnerability and exploit. Verify that the relevant system is patched.

## 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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file where event.type != "deletion" and
  file.extension : "spl" and
  file.path : "?:\\Windows\\System32\\spool\\PRINTERS\\*" and
  not process.name : ("spoolsv.exe",
                      "printfilterpipelinesvc.exe",
                      "PrintIsolationHost.exe",
                      "splwow64.exe",
                      "msiexec.exe",
                      "poqexec.exe")

Framework: MITRE ATT&CK^TM

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/

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