Detection: Print Spooler Failed to Load a Plug-in

Updated Date: 2024-05-28 ID: 1adc9548-da7c-11eb-8f13-acde48001122 Author: Mauricio Velazco, Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects driver load errors in the Windows PrintService Admin logs, specifically identifying issues related to CVE-2021-34527 (PrintNightmare). It triggers on error messages indicating the print spooler failed to load a plug-in module, such as "meterpreter.dll," with error code 0x45A. This detection method leverages specific event codes and error messages. This activity is significant as it may indicate an exploitation attempt of a known vulnerability. If confirmed malicious, an attacker could gain unauthorized code execution on the affected system, leading to potential system compromise.

1`printservice` ((ErrorCode="0x45A" (EventCode="808" OR EventCode="4909")) OR ("The print spooler failed to load a plug-in module" OR "\\drivers\\x64\\")) 
2| stats count min(_time) as firstTime max(_time) as lastTime by OpCode EventCode ComputerName Message 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `print_spooler_failed_to_load_a_plug_in_filter`

Data Source

Name Platform Sourcetype Source Supported App
Windows Event Log Printservice 808 Windows icon Windows 'WinEventLog' 'WinEventLog:Microsoft-Windows-PrintService/Admin' N/A

Macros Used

Name Value
printservice source="wineventlog:microsoft-windows-printservice/operational" OR source="WinEventLog:Microsoft-Windows-PrintService/Admin"
print_spooler_failed_to_load_a_plug_in_filter search *
print_spooler_failed_to_load_a_plug_in_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1547.012 Print Processors Persistence
T1547 Boot or Logon Autostart Execution Privilege Escalation
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
Earth Lusca

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

You will need to ensure PrintService Admin and Operational logs are being logged to Splunk from critical or all systems.

Known False Positives

False positives are unknown and filtering may be required.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Suspicious printer spooler errors have occured on endpoint $ComputerName$ with EventCode $EventCode$. 72 80 90
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset WinEventLog:Microsoft-Windows-PrintService/Admin WinEventLog
Integration ✅ Passing Dataset WinEventLog:Microsoft-Windows-PrintService/Admin WinEventLog

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 2