Elastic
Start free trial
Loading

Network Connection via Registration Utility

Elastic Stack Serverless Security

Identifies the native Windows tools regsvr32.exe, regsvr64.exe, RegSvcs.exe, or RegAsm.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: eql

Rule indices:

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

Severity: low

Risk score: 21

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:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

Version: 101

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

sequence by process.entity_id
  [process where event.type == "start" and
   process.name : ("regsvr32.exe", "RegAsm.exe", "RegSvcs.exe") and
   not (
         (?process.Ext.token.integrity_level_name : "System" or ?winlog.event_data.IntegrityLevel : "System") and
         (process.parent.name : "msiexec.exe" or process.parent.executable : ("C:\\Program Files (x86)\\*.exe", "C:\\Program Files\\*.exe"))
       )
   ]
  [network where process.name : ("regsvr32.exe", "RegAsm.exe", "RegSvcs.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") and network.protocol != "dns"]

Framework: MITRE ATT&CKTM