Unusual Print Spooler Child Process

Last updated 4 months ago on 2025-03-20
Created 4 years ago on 2021-07-06

About

Detects unusual Print Spooler service (spoolsv.exe) child processes. This may indicate an attempt to exploit privilege escalation vulnerabilities related to the Printing Service on Windows.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Privilege EscalationUse Case: VulnerabilityData Source: Elastic DefendData Source: Windows Security Event LogsLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Privilege Escalation (TA0004)(opens in a new tab or window)

False Positive Examples
Install or update of a legitimate printing driver. Verify the printer driver file metadata such as manufacturer and signature information.
License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.process-*logs-system.security*logs-windows.forwarded*winlogbeat-*
Related Integrations

endpoint(opens in a new tab or window)

windows(opens in a new tab or window)

system(opens in a new tab or window)

Query
process where host.os.type == "windows" and event.type == "start" and
 process.parent.name : "spoolsv.exe" and process.command_line != null and
 (?process.Ext.token.integrity_level_name : "System" or ?winlog.event_data.IntegrityLevel : "System") and

 /* exclusions for FP control below */
 not process.name : ("splwow64.exe", "PDFCreator.exe", "acrodist.exe", "spoolsv.exe", "msiexec.exe", "route.exe", "WerFault.exe") and
 not process.command_line : "*\\WINDOWS\\system32\\spool\\DRIVERS*" and
 not (process.name : "net.exe" and process.command_line : ("*stop*", "*start*")) and
 not (process.name : ("cmd.exe", "powershell.exe") and process.command_line : ("*.spl*", "*\\program files*", "*route add*")) and
 not (process.name : "netsh.exe" and process.command_line : ("*add portopening*", "*rule name*")) and
 not (process.name : "regsvr32.exe" and process.command_line : "*PrintConfig.dll*") and
 not process.executable : (
    "?:\\Program Files (x86)\\CutePDF Writer\\CPWriter2.exe",
    "?:\\Program Files (x86)\\GPLGS\\gswin32c.exe"
 )

Install detection rules in Elastic Security

Detect Unusual Print Spooler Child Process in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).