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Elastic Docs ›Elastic Security Solution [master] ›Detections and alerts ›Prebuilt rule reference

Unusual Print Spooler Child Process

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Unusual Print Spooler Child Process

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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.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

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

Version: 100 (version history)

Added (Elastic Stack release): 7.14.0

Last modified (Elastic Stack release): 8.5.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Install or update of a legitimate printing driver. Verify the printer driver file metadata such as manufacturer and signature information.

Investigation guide

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Rule query
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process where event.type == "start" and process.parent.name :
"spoolsv.exe" 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*")











Threat mapping
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Framework: MITRE ATT&CKTM














Rule version history
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Version 100 (8.5.0 release)








    

  • 
Formatting only

    • 









Version 8 (8.4.0 release)








    

  • 
Formatting only

    • 









Version 6 (8.3.0 release)








    

  • 
Formatting only

    • 









Version 5 (8.2.0 release)








    

  • 

    Updated query, changed from:
    

    

    

    process where event.type == "start" and process.parent.name :
"spoolsv.exe" 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*")
    

    

    • 









Version 3 (8.1.0 release)








    

  • 

    Updated query, changed from:
    

    

    

    process where event.type == "start" and process.parent.name :
"spoolsv.exe" and user.id : "S-1-5-18" 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*")
    

    

    • 




















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