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Elastic Docs ›SIEM Guide [7.8] ›Detections (beta) ›Prebuilt rule reference

Network Connection via Regsvr

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Network Connection via Regsvr

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Identifies the native Windows tools regsvr32.exe and regsvr64.exe making a network connection. This may be indicative of an attacker bypassing allowlists or running arbitrary scripts via a signed Microsoft binary.

Rule type: query

Rule indices:

  • winlogbeat-*

Severity: low

Risk score: 21

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum signals per execution: 100

Tags:

  • Elastic
  • Windows

Version: 2 (version history)

Added (Elastic Stack release): 7.6.0

Last modified (Elastic Stack release): 7.7.0

Potential false positives

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Security testing may produce events like this. Activity of this kind performed by non-engineers and ordinary users is unusual.

Rule query

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process.name:(regsvr32.exe or regsvr64.exe) and event.action:"Network
connection detected (rule: NetworkConnect)" and not
destination.ip:(10.0.0.0/8 or 169.254.169.254 or 172.16.0.0/12 or
192.168.0.0/16)

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 2 (7.7.0 release)

Updated query, changed from: 

(process.name:regsvr32.exe or process.name:regsvr64.exe) and
event.action:"Network connection detected (rule: NetworkConnect)" and
not destination.ip:169.254.169.254/32 and not
destination.ip:10.0.0.0/8 and not destination.ip:172.16.0.0/12 and not
destination.ip:192.168.0.0/16
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