description = [[ Finds out what options are supported by an HTTP server by sending an OPTIONS request. Lists potentially risky methods. Optionally tests each method individually to see if they are subject to e.g. IP address restrictions. In this script, "potentially risky" methods are anything except GET, HEAD, POST, and OPTIONS. If the script reports potentially risky methods, they may not all be security risks, but you should check to make sure. This page lists the dangers of some common methods: http://www.owasp.org/index.php/Testing_for_HTTP_Methods_and_XST_%28OWASP-CM-008%29 The list of supported methods comes from the contents of the Allow and Public header fields. In verbose mode, a list of all methods is printed, followed by the list of potentially risky methods. Without verbose mode, only the potentially risky methods are shown. ]] --- -- @args http-methods.url-path The path to request. Defaults to -- /. -- @args http-methods.retest If defined, do a request using each method -- individually and show the response code. Use of this argument can -- make this script unsafe; for example DELETE / is -- possible. -- -- @output -- 80/tcp open http -- | http-methods: GET HEAD POST OPTIONS TRACE -- | Potentially risky methods: TRACE -- | See http://nmap.org/nsedoc/scripts/http-methods.html -- | GET / -> HTTP/1.1 200 OK -- | HEAD / -> HTTP/1.1 200 OK -- | POST / -> HTTP/1.1 200 OK -- | OPTIONS / -> HTTP/1.1 200 OK -- |_TRACE / -> HTTP/1.1 200 OK -- -- @usage -- nmap --script=http-methods.nse --script-args http-methods.retest=1 -- nmap --script=http-methods.nse --script-args http-methods.url-path=/website author = "Bernd Stroessenreuther " license = "Same as Nmap--See http://nmap.org/book/man-legal.html" categories = {"default", "safe"} require("http") require("nmap") require("shortport") require("stdnse") -- We don't report these methods except with verbosity. local UNINTERESTING_METHODS = { "GET", "HEAD", "POST", "OPTIONS" } local filter_out, merge_headers portrule = shortport.http action = function(host, port) local url_path, retest_http_methods local response, methods, options_status_line, output -- default vaules for script-args url_path = stdnse.get_script_args("http-methods.url-path") or "/" retest_http_methods = stdnse.get_script_args("http-methods.retest") ~= nil response = http.generic_request(host, port, "OPTIONS", url_path) if not response.status then stdnse.print_debug("http-methods: OPTIONS %s failed.", url_path) return end -- Cache in case retest is requested. options_status_line = response["status-line"] stdnse.print_debug("http-methods.nse: HTTP Status for OPTIONS is " .. response.status) if not (response.header["allow"] or response.header["public"]) then return string.format("No Allow or Public header in OPTIONS response (status code %d)", response.status) end -- The Public header is defined in RFC 2068, but was removed in its -- successor RFC 2616. It is implemented by at least IIS 6.0. methods = merge_headers(response.header, {"Allow", "Public"}) output = {} if nmap.verbosity() > 0 then output[#output + 1] = stdnse.strjoin(" ", methods) end local interesting = filter_out(methods, UNINTERESTING_METHODS) if #interesting > 0 then output[#output + 1] = "Potentially risky methods: " .. stdnse.strjoin(" ", interesting) output[#output + 1] = "See http://nmap.org/nsedoc/scripts/http-methods.html" end -- retest http methods if requested if retest_http_methods then local _ for _, method in ipairs(methods) do local str if method == "OPTIONS" then -- Use the saved value. str = options_status_line else response = http.generic_request(host, port, method, url_path) if not response.status then str = "Error getting response" else str = response["status-line"] end end output[#output + 1] = string.format("%s %s -> %s", method, url_path, str) end end return #output > 0 and stdnse.strjoin("\n", output) or nil end local function contains(t, elem) local _, e for _, e in ipairs(t) do if e == elem then return true end end return false end function filter_out(t, filter) local result = {} local _, e, f for _, e in ipairs(t) do if not contains(filter, e) then result[#result + 1] = e end end return result end -- Split header field contents on commas and return a table without duplicates. function merge_headers(headers, names) local seen = {} local result = {} for _, name in ipairs(names) do name = string.lower(name) if headers[name] then for _, v in ipairs(stdnse.strsplit(",%s*", headers[name])) do if not seen[v] then result[#result + 1] = v end seen[v] = true end end end return result end