Network Connection via Signed Binary

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Binaries signed with trusted digital certificates can execute on Windows systems protected by digital signature validation. Adversaries may use these binaries to live off the land and execute malicious files that could bypass application allowlists and signature validation.

Rule type: eql

Rule indices:

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

Severity: low

Risk score: 21

Runs every: 5m

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
  • Defense Evasion

Version: 101

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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sequence by process.entity_id
  [process where (process.name : "expand.exe" or process.name : "extrac32.exe" or
                 process.name : "ieexec.exe" or process.name : "makecab.exe") and
                 event.type == "start"]
  [network where (process.name : "expand.exe" or process.name : "extrac32.exe" or
                 process.name : "ieexec.exe" or process.name : "makecab.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")]

Framework: MITRE ATT&CKTM