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Suspicious Process Creation CallTrace

Elastic Stack Serverless Security

Identifies when a process is created and immediately accessed from an unknown memory code region and by the same parent process. This may indicate a code injection or hollowing attempt.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Defense Evasion

Version: 100

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

sequence by host.id with maxspan=1m
  [process where event.code == "1" and
   /* sysmon process creation */
   process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe", "eqnedt32.exe", "fltldr.exe",
                          "mspub.exe", "msaccess.exe","cscript.exe", "wscript.exe", "rundll32.exe", "regsvr32.exe",
                          "mshta.exe", "wmic.exe", "cmstp.exe", "msxsl.exe") and

   /* noisy FP patterns */
   not (process.parent.name : "EXCEL.EXE" and process.executable : "?:\\Program Files\\Microsoft Office\\root\\Office*\\ADDINS\\*.exe") and
   not (process.executable : "?:\\Windows\\splwow64.exe" and process.args in ("8192", "12288") and process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe")) and
   not (process.parent.name : "rundll32.exe" and process.parent.args : ("?:\\WINDOWS\\Installer\\MSI*.tmp,zzzzInvokeManagedCustomActionOutOfProc", "--no-sandbox")) and
   not (process.executable :
            ("?:\\Program Files (x86)\\Microsoft\\EdgeWebView\\Application\\*\\msedgewebview2.exe",
             "?:\\Program Files\\Adobe\\Acrobat DC\\Acrobat\\Acrobat.exe",
             "?:\\Windows\\SysWOW64\\DWWIN.EXE") and
        process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe")) and
   not (process.parent.name : "regsvr32.exe" and process.parent.args : ("?:\\Program Files\\*", "?:\\Program Files (x86)\\*"))
   ] by process.parent.entity_id, process.entity_id
  [process where event.code == "10" and
   /* Sysmon process access event from unknown module */
   winlog.event_data.CallTrace : "*UNKNOWN*"] by process.entity_id, winlog.event_data.TargetProcessGUID

Framework: MITRE ATT&CKTM