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Elastic Docs ›Elastic Security Solution [7.16] ›Detections and alerts ›Prebuilt rule reference

Network Connection via Certutil

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Network Connection via Certutil

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Identifies certutil.exe making a network connection. Adversaries could abuse certutil.exe to download a certificate, or malware, from a remote URL.

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

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Command and Control

Version: 6 (version history)

Added (Elastic Stack release): 7.7.0

Last modified (Elastic Stack release): 7.14.0

Rule authors: Elastic

Rule license: Elastic License v2

Rule query

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sequence by process.entity_id [process where process.name :
"certutil.exe" and event.type == "start"] [network where
process.name : "certutil.exe" and not cidrmatch(destination.ip,
"10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12",
"192.0.0.0/24", "192.0.0.0/29",
"192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32",
"192.0.0.171/32", "192.0.2.0/24", "192.31.196.0/24",
"192.52.193.0/24", "192.168.0.0/16",
"192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10", "192.175.48.0/24",
"198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4",
"::1", "FE80::/10", "FF00::/8")]

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 6 (7.14.0 release)

  • Updated query, changed from:

    sequence by process.entity_id [process where process.name :
"certutil.exe" and event.type == "start"] [network where
process.name : "certutil.exe" and not cidrmatch(destination.ip,
"10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16")]
Version 5 (7.12.0 release)
  • Formatting only
Version 4 (7.10.0 release)

  • Updated query, changed from:

    event.category:network and event.type:connection and
process.name:certutil.exe and not destination.ip:(10.0.0.0/8 or
172.16.0.0/12 or 192.168.0.0/16)
Version 3 (7.9.1 release)
  • Formatting only
Version 2 (7.9.0 release)

  • Updated query, changed from:

    process.name:certutil.exe and event.action:"Network connection
detected (rule: NetworkConnect)" and not destination.ip:(10.0.0.0/8 or
172.16.0.0/12 or 192.168.0.0/16)
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