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splunk-security_content/detections/endpoint/print_spooler_adding_a_printer_driver.yml

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name: Print Spooler Adding A Printer Driver
id: 313681a2-da8e-11eb-adad-acde48001122
version: 1
date: '2021-07-01'
author: Mauricio Velazco, Michael Haag, Teoderick Contreras, Splunk
type: TTP
datamodel:
- Endpoint
description: 'The following analytic identifies new printer drivers being load by
utilizing the Windows PrintService operational logs, EventCode 316. This was identified
during our testing of CVE-2021-34527 previously (CVE-2021-1675) or PrintNightmare.
\
Within the proof of concept code, the following event will occur - "Printer driver
1234 for Windows x64 Version-3 was added or updated. Files:- UNIDRV.DLL, kernelbase.dll,
evil.dll. No user action is required." \
During triage, isolate the endpoint and review for source of exploitation. Capture
any additional file modification events and review the source of where the exploitation
began.'
search: '`printservice` EventCode=316 category = "Adding a printer driver" Message
= "*kernelbase.dll,*" Message = "*UNIDRV.DLL,*" Message = "*.DLL.*" | stats count
min(_time) as firstTime max(_time) as lastTime by OpCode EventCode ComputerName
Message | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
| `print_spooler_adding_a_printer_driver_filter`'
how_to_implement: You will need to ensure PrintService Admin and Operational logs
are being logged to Splunk from critical or all systems.
known_false_positives: Unknown. This may require filtering.
references:
- https://twitter.com/MalwareJake/status/1410421445608476679?s=20
- https://www.truesec.com/hub/blog/fix-for-printnightmare-cve-2021-1675-exploit-to-keep-your-print-servers-running-while-a-patch-is-not-available
- https://www.truesec.com/hub/blog/exploitable-critical-rce-vulnerability-allows-regular-users-to-fully-compromise-active-directory-printnightmare-cve-2021-1675
- https://www.reddit.com/r/msp/comments/ob6y02/critical_vulnerability_printnightmare_exposes
tags:
analytic_story:
- PrintNightmare CVE-2021-34527
confidence: 90
context:
- Source:Endpoint
- Stage:Persistence
- Stage:Privilege Escalation
- Stage:Defense Evasion
- Scope:Inbound
cve:
- CVE-2021-34527
- CVE-2021-1675
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1547.012/printnightmare/windows-printservice_operational.log
impact: 80
kill_chain_phases:
- Exploitation
message: Suspicious print driver was loaded on endpoint $ComputerName$.
mitre_attack_id:
- T1547.012
- T1547
observable:
- name: ComputerName
type: Endpoint
role:
- Victim
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- OpCode
- EventCode
- ComputerName
- Message
risk_score: 72
security_domain: endpoint
asset_type: Endpoint