Potential Command and Control via Internet Exploreredit

Identifies instances of Internet Explorer (iexplore.exe) being started via the Component Object Model (COM) making unusual network connections. Adversaries could abuse Internet Explorer via COM to avoid suspicious processes making network connections and bypass host-based firewall restrictions.

Rule type: eql

Rule indices:

  • logs-endpoint.events.library-*
  • logs-endpoint.events.process-*
  • logs-endpoint.events.network-*

Severity: medium

Risk score: 47

Runs every: 5m

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

Maximum alerts per execution: 100

References: None


  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Command and Control
  • Data Source: Elastic Defend

Version: 106

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule queryedit

sequence by host.id, user.name with maxspan = 5s
  [library where host.os.type == "windows" and dll.name : "IEProxy.dll" and process.name : ("rundll32.exe", "regsvr32.exe")]
  [process where host.os.type == "windows" and event.type == "start" and process.parent.name : "iexplore.exe" and process.parent.args : "-Embedding"]
  /* IE started via COM in normal conditions makes few connections, mainly to Microsoft and OCSP related domains, add FPs here */
  [network where host.os.type == "windows" and network.protocol == "dns" and process.name : "iexplore.exe" and
   not dns.question.name :
  ] /* with runs=5 */