Elastic Defend high stable eql

Linux Reverse Shell via netcat

Detects the creation of a reverse shell through netcat. Attackers may spawn reverse shells to establish persistence onto a target system.

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Detection Logic

sequence by process.entity_id with maxspan=5s
  [process where event.type == "start" and event.action == "exec" and 
   process.name in ("nc", "ncat", "netcat", "netcat.openbsd", "netcat.traditional", "nc.openbsd", "nc.traditional") and process.args_count >= 3 and 
   process.parent.name in ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") and process.args == "-e" and
   not process.args like~ ("-*z*", "-*l*")]
  [network where event.type == "start" and event.action in ("connection_attempted", "connection_accepted") and 
   process.name in ("nc", "ncat", "netcat", "netcat.openbsd", "netcat.traditional", "nc.openbsd", "nc.traditional") 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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