--- -- POP3 functions. -- -- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html local base64 = require "base64" local comm = require "comm" local match = require "match" local stdnse = require "stdnse" local string = require "string" local table = require "table" _ENV = stdnse.module("pop3", stdnse.seeall) local HAVE_SSL, openssl = pcall(require,'openssl') err = { none = 0, userError = 1, pwError = 2, informationMissing = 3, OpenSSLMissing = 4, } --- -- Check a POP3 response for "+OK". -- @param line First line returned from an POP3 request. -- @return The string "+OK" if found or nil otherwise. function stat(line) return string.match(line, "+OK") end --- -- Try to log in using the USER/PASS commands. -- @param socket Socket connected to POP3 server. -- @param user User string. -- @param pw Password string. -- @return Status (true or false). -- @return Error code if status is false. function login_user(socket, user, pw) socket:send("USER " .. user .. "\r\n") local status, line = socket:receive_lines(1) if not stat(line) then return false, err.user_error end socket:send("PASS " .. pw .. "\r\n") status, line = socket:receive_lines(1) if stat(line) then return true, err.none else return false, err.pwError end end --- -- Try to login using the the AUTH command using SASL/Plain method. -- @param socket Socket connected to POP3 server. -- @param user User string. -- @param pw Password string. -- @return Status (true or false). -- @return Error code if status is false. function login_sasl_plain(socket, user, pw) local auth64 = base64.enc(user .. "\0" .. user .. "\0" .. pw) socket:send("AUTH PLAIN " .. auth64 .. "\r\n") local status, line = socket:receive_lines(1) if stat(line) then return true, err.none else return false, err.pwError end end --- -- Try to login using the AUTH command using SASL/Login method. -- @param user User string. -- @param pw Password string. -- @param pw String containing password to login. -- @return Status (true or false). -- @return Error code if status is false. function login_sasl_login(socket, user, pw) local user64 = base64.enc(user) local pw64 = base64.enc(pw) socket:send("AUTH LOGIN\r\n") local status, line = socket:receive_lines(1) if not base64.dec(string.sub(line, 3)) == "User Name:" then return false, err.userError end socket:send(user64) local status, line = socket:receive_lines(1) if not base64.dec(string.sub(line, 3)) == "Password:" then return false, err.userError end socket:send(pw64) local status, line = socket:receive_lines(1) if stat(line) then return true, err.none else return false, err.pwError end end --- -- Try to login using the APOP command. -- @param socket Socket connected to POP3 server. -- @param user User string. -- @param pw Password string. -- @param challenge String containing challenge from POP3 server greeting. -- @return Status (true or false). -- @return Error code if status is false. function login_apop(socket, user, pw, challenge) if type(challenge) ~= "string" then return false, err.informationMissing end local apStr = stdnse.tohex(openssl.md5(challenge .. pw)) socket:send(("APOP %s %s\r\n"):format(user, apStr)) local status, line = socket:receive_lines(1) if (stat(line)) then return true, err.none else return false, err.pwError end end --- -- Asks a POP3 server for capabilities. -- -- See RFC 2449. -- @param host Host to be queried. -- @param port Port to connect to. -- @return Table containing capabilities or nil on error. -- @return nil or String error message. function capabilities(host, port) local socket, line, bopt, first_line = comm.tryssl(host, port, "" , {request_timeout=10000, recv_before=true}) if not socket then return nil, "Could Not Connect" end if not stat(first_line) then return nil, "No Response" end local capas = {} if string.find(first_line, "<[%p%w]+>") then capas.APOP = {} end local status = socket:send("CAPA\r\n") if( not(status) ) then return nil, "Failed to send" end status, line = socket:receive_buf(match.pattern_limit("%.", 2048), false) if( not(status) ) then return nil, "Failed to receive" end socket:close() local lines = stdnse.strsplit("\r\n",line) if not stat(table.remove(lines,1)) then capas.capa = false return capas end for _, line in ipairs(lines) do if ( line and #line>0 ) then local capability = line:sub(line:find("[%w-]+")) line = line:sub(#capability + 2) if ( line ~= "" ) then capas[capability] = stdnse.strsplit(" ", line) else capas[capability] = {} end end end return capas end --- -- Try to login using the AUTH command using SASL/CRAM-MD5 method. -- @param socket Socket connected to POP3 server. -- @param user User string. -- @param pw Password string. -- @return Status (true or false). -- @return Error code if status is false. function login_sasl_crammd5(socket, user, pw) socket:send("AUTH CRAM-MD5\r\n") local status, line = socket:receive_lines(1) local challenge = base64.dec(string.sub(line, 3)) local digest = stdnse.tohex(openssl.hmac('md5', pw, challenge)) local authStr = base64.enc(user .. " " .. digest) socket:send(authStr .. "\r\n") local status, line = socket:receive_lines(1) if stat(line) then return true, err.none else return false, err.pwError end end -- Overwrite functions requiring OpenSSL if we got no OpenSSL. if not HAVE_SSL then local no_ssl = function() return false, err.OpenSSLMissing end login_apop = no_ssl login_sasl_crammd5 = no_ssl end return _ENV;