Suspicious MS Outlook Child Process

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Identifies suspicious child processes of Microsoft Outlook. These child processes are often associated with spear phishing activity.

Rule type: eql

Rule indices:

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

Severity: low

Risk score: 21

Runs every: 5 minutes

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

Maximum alerts per execution: 100

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Initial Access

Version: 10 (version history)

Added (Elastic Stack release): 7.6.0

Last modified (Elastic Stack release): 8.2.0

Rule authors: Elastic

Rule license: Elastic License v2

Investigation guide

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## Config

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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process where event.type in ("start", "process_started") and
process.parent.name : "outlook.exe" and process.name :
("Microsoft.Workflow.Compiler.exe", "arp.exe", "atbroker.exe",
"bginfo.exe", "bitsadmin.exe", "cdb.exe",
"certutil.exe", "cmd.exe", "cmstp.exe", "cscript.exe", "csi.exe",
"dnx.exe", "dsget.exe", "dsquery.exe",
"forfiles.exe", "fsi.exe", "ftp.exe", "gpresult.exe", "hostname.exe",
"ieexec.exe", "iexpress.exe", "installutil.exe",
"ipconfig.exe", "mshta.exe", "msxsl.exe", "nbtstat.exe", "net.exe",
"net1.exe", "netsh.exe", "netstat.exe", "nltest.exe", "odbcconf.exe",
"ping.exe", "powershell.exe", "pwsh.exe",
"qprocess.exe", "quser.exe", "qwinsta.exe", "rcsi.exe", "reg.exe",
"regasm.exe", "regsvcs.exe", "regsvr32.exe",
"sc.exe", "schtasks.exe", "systeminfo.exe", "tasklist.exe",
"tracert.exe", "whoami.exe", "wmic.exe", "wscript.exe", "xwizard.exe")

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 10 (8.2.0 release)
  • Formatting only
Version 9 (7.13.0 release)
  • Updated query, changed from:

    event.category:process and event.type:(start or process_started) and
    process.parent.name:outlook.exe and
    process.name:(Microsoft.Workflow.Compiler.exe or arp.exe or
    atbroker.exe or bginfo.exe or bitsadmin.exe or cdb.exe or
    certutil.exe or cmd.exe or cmstp.exe or cscript.exe or csi.exe or
    dnx.exe or dsget.exe or dsquery.exe or forfiles.exe or fsi.exe or
    ftp.exe or gpresult.exe or hostname.exe or ieexec.exe or iexpress.exe
    or installutil.exe or ipconfig.exe or mshta.exe or msxsl.exe or
    nbtstat.exe or net.exe or net1.exe or netsh.exe or netstat.exe or
    nltest.exe or odbcconf.exe or ping.exe or powershell.exe or pwsh.exe
    or qprocess.exe or quser.exe or qwinsta.exe or rcsi.exe or reg.exe or
    regasm.exe or regsvcs.exe or regsvr32.exe or sc.exe or schtasks.exe or
    systeminfo.exe or tasklist.exe or tracert.exe or whoami.exe or
    wmic.exe or wscript.exe or xwizard.exe)
Version 8 (7.12.0 release)
  • Formatting only
Version 7 (7.11.2 release)
  • Formatting only
Version 6 (7.11.0 release)
  • Formatting only
Version 5 (7.10.0 release)
  • Formatting only
Version 4 (7.9.1 release)
  • Formatting only
Version 3 (7.9.0 release)
  • Updated query, changed from:

    event.action:"Process Create (rule: ProcessCreate)" and
    process.parent.name:outlook.exe and
    process.name:(Microsoft.Workflow.Compiler.exe or arp.exe or
    atbroker.exe or bginfo.exe or bitsadmin.exe or cdb.exe or certutil.exe
    or cmd.exe or cmstp.exe or cscript.exe or csi.exe or dnx.exe or
    dsget.exe or dsquery.exe or forfiles.exe or fsi.exe or ftp.exe or
    gpresult.exe or hostname.exe or ieexec.exe or iexpress.exe or
    installutil.exe or ipconfig.exe or mshta.exe or msxsl.exe or
    nbtstat.exe or net.exe or net1.exe or netsh.exe or netstat.exe or
    nltest.exe or odbcconf.exe or ping.exe or powershell.exe or pwsh.exe
    or qprocess.exe or quser.exe or qwinsta.exe or rcsi.exe or reg.exe or
    regasm.exe or regsvcs.exe or regsvr32.exe or sc.exe or schtasks.exe or
    systeminfo.exe or tasklist.exe or tracert.exe or whoami.exe or
    wmic.exe or wscript.exe or xwizard.exe)
Version 2 (7.7.0 release)
  • Updated query, changed from:

    event.action:"Process Create (rule: ProcessCreate)" and
    process.parent.name:"outlook.exe" and process.name:("arp.exe" or
    "dsquery.exe" or "dsget.exe" or "gpresult.exe" or "hostname.exe" or
    "ipconfig.exe" or "nbtstat.exe" or "net.exe" or "net1.exe" or
    "netsh.exe" or "netstat.exe" or "nltest.exe" or "ping.exe" or
    "qprocess.exe" or "quser.exe" or "qwinsta.exe" or "reg.exe" or
    "sc.exe" or "systeminfo.exe" or "tasklist.exe" or "tracert.exe" or
    "whoami.exe" or "bginfo.exe" or "cdb.exe" or "cmstp.exe" or "csi.exe"
    or "dnx.exe" or "fsi.exe" or "ieexec.exe" or "iexpress.exe" or
    "installutil.exe" or "Microsoft.Workflow.Compiler.exe" or
    "msbuild.exe" or "mshta.exe" or "msxsl.exe" or "odbcconf.exe" or
    "rcsi.exe" or "regsvr32.exe" or "xwizard.exe" or "atbroker.exe" or
    "forfiles.exe" or "schtasks.exe" or "regasm.exe" or "regsvcs.exe" or
    "cmd.exe" or "cscript.exe" or "powershell.exe" or "pwsh.exe" or
    "wmic.exe" or "wscript.exe" or "bitsadmin.exe" or "certutil.exe" or
    "ftp.exe")