Adding Jenkins-CI Login Scanner

Per Github issue rapid7#3871 (RM8774), I have added a
login scanner module for Jenkins-CI installations.

Author: nstarke

modules/auxiliary/scanner/http/jenkins_login.rb

@@ -0,0 +1,80 @@
+##
+# This module requires Metasploit: http//metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+require 'pry'
+require 'msf/core'
+
+class Metasploit3 < Msf::Auxiliary
+
+  include Msf::Exploit::Remote::HttpClient
+  include Msf::Auxiliary::Report
+  include Msf::Auxiliary::AuthBrute
+  include Msf::Auxiliary::Scanner
+
+  def initialize
+    super(
+      'Name'           => 'Jenkins-CI Login Utility',
+      'Description'    => 'This module simply attempts to login to a Jenkins-CI instance using a specific user/pass.',
+      'Author'         => [ 'NS', 'Nicholas Starke <starke.nicholas[at]gmail.com>', 'nstarke' ],
+      'License'        => MSF_LICENSE
+    )
+
+    register_options(
+      [
+        Opt::RPORT(8080),
+        OptAddress.new('RHOST', [ true, "The target address", true])
+      ], self.class)
+
+    register_autofilter_ports([ 80, 443, 8080, 8081, 8000 ])
+    deregister_options('RHOSTS')
+  end
+
+  def run
+    each_user_pass do |user, pass|
+      next if (user.blank? or pass.blank?)
+      vprint_status("Trying #{user} : #{pass}")
+      if (datastore['SSL'].to_s.match(/^(t|y|1)/i))
+        protocol = 'https://'
+      else
+        protocol = 'http://'
+      do_login(user, pass)
+      end
+    end
+  end
+
+  def do_login(user, pass)
+    begin
+      post_data = {
+        'j_username' => user,
+        'j_password' => pass
+      }
+      res = send_request_cgi({
+        'uri' => '/j_acegi_security_check',
+        'method' => 'POST',
+        'vars_post' => post_data
+      })
+    rescue ::Rex::ConnectionError => e
+      vprint_error("#{rhost}:#{rport}#{url} - #{e}")
+      return
+    end
+    if not res
+      vprint_error("#{rhost}:#{rport}#{url} - #{e}")
+      return
+    end
+    if !res.headers['location'].include? 'loginError'
+      print_good("SUCCESSFUL LOGIN. '#{user} : #{pass}'")
+      report_hash = {
+        :host => datastore['RHOST'],
+        :port => datastore['RPORT'],
+        :sname => 'jenkins',
+        :user => user,
+        :pass => pass,
+        :active => true,
+        :type => 'password'
+      }
+      report_auth_info(report_hash)
+      return :next_user
+    end
+  end
+end