--- -- Functions for proxy testing. -- -- @args proxy.url Url that will be requested to the proxy -- @args proxy.pattern Pattern that will be searched inside the request results -- -- @author Joao Correa -- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html local dns = require "dns" local ipOps = require "ipOps" local nmap = require "nmap" local stdnse = require "stdnse" local string = require "string" local stringaux = require "stringaux" _ENV = stdnse.module("proxy", stdnse.seeall) -- Start of local functions --- check function, checks for all valid returned status --- If any of the HTTP status below is found, the proxy is potentially open --- The script tries to split header from body before checking for status --@param result connection result --@return true if any of the status is found, otherwise false local function check_code(result) if result then local header if result:match( "\r?\n\r?\n" ) then result = result:match( "^(.-)\r?\n\r?\n(.*)$" ) end if result:lower():match("^http/%d%.%d%s*200") then return true end if result:lower():match("^http/%d%.%d%s*30[12]") then return true end end return false end --- check pattern, searches a pattern inside a response with multiple lines --@param result Connection result --@param pattern The pattern to be searched --@return true if pattern is found, otherwise false local function check_pattern(result, pattern) local lines = stringaux.strsplit("\n", result) for i, line in ipairs(lines) do if line:lower():match(pattern:lower()) then return true end end return false end --- check, decides what kind of check should be done on the response, --- depending if a specific pattern is being used --@param result Connection result --@param pattern The pattern that should be checked (must be false, in case of --code check) --@return true, if the performed check returns true, otherwise false local function check(result, pattern) local s_pattern = false local s_code = check_code(result) if s_code and pattern then s_pattern = check_pattern(result, pattern) end return s_code, s_pattern end --- Performs a request to the web server and calls check to check if -- the response is a valid result -- --@param socket The socket to send the request through --@param req The request to be sent --@param pattern The pattern to check for valid result --@return check_status True or false. If pattern was used, depends on pattern check result. If not, depends on code check result. --@return result The result of the request --@return code_status True or false. If pattern was used, returns the result of code checking for the same result. If pattern was not used, is nil. local function test(socket, req, pattern) local status, result = socket:send(req) if not status then socket:close() return false, result end status, result = socket:receive() if not status then socket:close() return false, result end socket:close() local s_code, s_pattern = check(result, pattern) if result and pattern then return s_pattern, result, s_code end if result then return s_code, result, nil end return false, nil, nil end --- Builds the GET request and calls test -- @param host The host table -- @param port The port table -- @param proxyType The proxy type to be tested, might be 'socks4', 'socks5' or 'http' -- @param test_url The url to send the request -- @param hostname The hostname of the server to send the request -- @param pattern The pattern to check for valid result -- @return the result of the function test (status and the request result) function test_get(host, port, proxyType, test_url, hostname, pattern) local status, socket = connectProxy(host, port, proxyType, hostname) if not status then return false, socket end local req = "GET " .. test_url .. " HTTP/1.0\r\nHost: " .. hostname .. "\r\n\r\n" stdnse.debug1("GET Request: %s", req) return test(socket, req, pattern) end --- Builds the HEAD request and calls test -- @param host The host table -- @param port The port table -- @param proxyType The proxy type to be tested, might be 'socks4', 'socks5' or 'http' -- @param test_url The url te send the request -- @param hostname The hostname of the server to send the request -- @param pattern The pattern to check for valid result -- @return the result of the function test (status and the request result) function test_head(host, port, proxyType, test_url, hostname, pattern) local status, socket = connectProxy(host, port, proxyType, hostname) if not status then return false, socket end local req = "HEAD " .. test_url .. " HTTP/1.0\r\nHost: " .. hostname .. "\r\n\r\n" stdnse.debug1("HEAD Request: %s", req) return test(socket, req, pattern) end --- Builds the CONNECT request and calls test -- @param host The host table -- @param port The port table -- @param proxyType The proxy type to be tested, might be 'socks4', 'socks5' or 'http' -- @param hostname The hostname of the server to send the request -- @return the result of the function test (status and the request result) function test_connect(host, port, proxyType, hostname) local status, socket = connectProxy(host, port, proxyType, hostname) if not status then return false, socket end local req = "CONNECT " .. hostname .. ":80 HTTP/1.0\r\n\r\n" stdnse.debug1("CONNECT Request: %s", req) return test(socket, req, false) end --- Checks if any parameter was used in old or new syntax -- and return the parameters -- @return url the proxy.url parameter -- @return pattern the proxy.pattern parameter function return_args() local url = false local pattern = false if nmap.registry.args['proxy.url'] then url = nmap.registry.args['proxy.url'] elseif nmap.registry.args.proxy and nmap.registry.args.proxy.url then url = nmap.registry.args.proxy.url end if nmap.registry.args['proxy.pattern'] then pattern = nmap.registry.args['proxy.pattern'] elseif nmap.registry.args.proxy and nmap.registry.args.proxy.url then pattern = nmap.registry.args.proxy.pattern end return url, pattern end --- Creates a socket, performs proxy handshake if necessary --- and returns it -- @param host The host table -- @param port The port table -- @param proxyType A string with the proxy type. Might be "http","socks4" or "socks5" -- @param hostname The proxy destination hostname -- @return status True if handshake succeeded, false otherwise -- @return socket A socket with the handshake already done, or an error if function connectProxy(host, port, proxyType, hostname) local socket = nmap.new_socket() socket:set_timeout(10000) local status, err = socket:connect(host, port) if not status then socket:close() return false, err end if proxyType == "http" then return true, socket end if proxyType == "socks4" then return socksHandshake(socket, 4, hostname) end if proxyType == "socks5" then return socksHandshake(socket, 5, hostname) end socket:close() return false, "Invalid proxyType" end --- Performs a socks handshake on a socket and returns it -- @param socket The socket where the handshake will be performed -- @param version The socks version (might be 4 or 5) -- @param hostname The proxy destination hostname -- @return status True if handshake succeeded, false otherwise -- @return socket A socket with the handshake already done, or an error if -- status is false function socksHandshake(socket, version, hostname) local status, ip = dns.query(hostname) if not status then return false, "Unable to resolve hostname" end if version == 4 then local payload = '\x04\x01\x00\x50' .. ipOps.ip_to_str(ip) .. '\x6e\x6d\x61\x70\x00' local status, response = socket:send(payload) if not status then socket:close() return false, response end status, response = socket:receive() if not status then socket:close() return false, response end if #response < 2 then socket:close() return false, "Invalid or unknown SOCKS response" end local request_status = string.byte(response, 2) local err = string.format("Unknown response (0x%02x)", request_status) if(request_status == 0x5a) then stdnse.debug1('Socks4: Received "Request Granted" from proxy server') return true, socket end if(request_status == 0x5b) then err = "Request rejected or failed" elseif (request_status == 0x5c) then err = "request failed because client is not running identd" elseif (request_status == 0x5d) then err = "request failed because client program and identd report different user-ids" end stdnse.debug1('Socks4: Received "%s" from proxy server', err) return false, err end if version == 5 then local payload = '\x05\x01\x00' local status, err = socket:send(payload) if not status then socket:close() return false, err end local auth status, auth = socket:receive() local r2 = string.byte(auth,2) -- If Auth is required, proxy is closed, skip next test if(r2 ~= 0x00) then err = "Authentication Required" else -- If no Auth is required, try to establish connection stdnse.debug1("Socks5: No authentication required") -- Socks5 second payload: Version, Command, Null, Address type, Ip-Address, Port number payload = '\x05\x01\x00\x01' .. ipOps.ip_to_str(ip) .. '\x00\x50' status, err = socket:send(payload) if not status then socket:close() return false, err end local z status, z = socket:receive() if not status then socket:close() return false, z end local request_status = string.byte(z, 2) err = string.format("Unknown response (0x%02x)", request_status) if (request_status == 0x00) then stdnse.debug1('Socks5: Received "Request Granted" from proxy server') return true, socket elseif(request_status == 0x01) then err = "General Failure" elseif (request_status == 0x02) then err = "Connection not allowed by ruleset" elseif (request_status == 0x03) then err = "Network unreachable" elseif (request_status == 0x04) then err = "Host unreachable" elseif (request_status == 0x05) then err = "Connection refused by destination host" elseif (request_status == 0x06) then err = "TTL Expired" elseif (request_status == 0x07) then err = "command not supported / protocol error" elseif (request_status == 0x08) then err = "Address type not supported" end end stdnse.debug1('Socks5: Received "%s" from proxy server', err) return false, err end return false, "Invalid SOCKS version" end --- Checks if two different responses are equal, -- if true, the proxy server might be redirecting the requests -- to a default page -- -- Functions splits body from head before comparing, to avoid session -- variables, cookies... -- -- @param resp1 A string with the response for the first request -- @param resp2 A string with the response for the second request -- @return bool true if both responses are equal, otherwise false function redirectCheck(resp1, resp2) local body1, body2, _ if resp1:match( "\r?\n\r?\n" ) then local body1 _, body1 = resp1:match( "^(.-)\r?\n\r?\n(.*)$" ) if resp2:match( "\r?\n\r?\n" ) then _, body2 = resp2:match( "^(.-)\r?\n\r?\n(.*)$" ) if body1 == body2 then return true end end end return false end return _ENV;