Elastic Defend high stable eql

Hidden Executable Initiated Egress Network Connection

This rule detects when a hidden process executes a command that includes an IP address as an argument and initiates an egress network connection. This may indicate command and control behavior.

View Source

Detection Logic

sequence by process.entity_id with maxspan=10s
  [process where event.type == "start" and event.action == "exec" and process.name like ".*" and
   process.command_line regex ".*[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}.*" and
   not (
     process.executable like (
       "/home/*/.npm/_npx/*/node_modules/opencode-ai/bin/.opencode",
       "/home/*/.local/share/fnm/node-versions/*/installation/lib/node_modules/opencode-ai/bin/.opencode"
     ) or
     process.parent.executable == "/usr/bin/buildah"
  )]
  [network where event.type == "start" and event.action == "connection_attempted" and not (
     destination.ip == null or destination.ip == "0.0.0.0" or 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"
     )
   )
  ]

Field Validations

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