o [NSE] Added the script http-proxy-brute that performs brute force password

guessing against HTTP proxy servers. [Patrik]

CHANGELOG

@@ -1,5 +1,8 @@
 # Nmap Changelog ($Id$); -*-text-*-
 
+o [NSE] Added the script http-proxy-brute that performs brute force password
+  guessing against HTTP proxy servers. [Patrik]
+
 o [NSE] Added the script socks-brute that performs brute force password
   guessing against SOCKS 5 servers. [Patrik]
 

scripts/http-proxy-brute.nse

@@ -0,0 +1,111 @@
+description = [[
+Performs brute force password guessing against a HTTP proxy server
+]]
+
+---
+-- @usage
+-- nmap --script http-proxy-brute -p 8080 <host>
+--
+-- @output
+-- PORT     STATE SERVICE
+-- 8080/tcp open  http-proxy
+-- | http-proxy-brute: 
+-- |   Accounts
+-- |     patrik:12345 - Valid credentials
+-- |   Statistics
+-- |_    Performed 6 guesses in 2 seconds, average tps: 3
+--
+-- @args http-proxy-brute.url sets an alternative URL to use when brute forcing
+--       (default: http://scanme.insecure.org)
+-- @args http-proxy-brute.method changes the HTTP method to use when performing
+--       brute force guessing (default: HEAD)
+
+author = "Patrik Karlsson"
+license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
+
+-- maybe the script does not need to be in the external category
+-- as most request should not "leave" the proxy.
+categories = {"brute", "intrusive", "external"}
+
+require 'base64'
+require 'brute'
+require 'http'
+require 'shortport'
+
+portrule = shortport.port_or_service({8123,3128,8000,8080},{'polipo','squid-http','http-proxy'})
+
+local arg_url 		= stdnse.get_script_args(SCRIPT_NAME .. '.url') or 'http://scanme.nmap.org/'
+local arg_method	= stdnse.get_script_args(SCRIPT_NAME .. '.method') or "HEAD"
+
+Driver = {
+	
+	new = function(self, host, port)
+		local o = { host = host, port = port }
+		setmetatable(o, self)
+		self.__index = self
+		return o
+	end,
+	
+	connect = function( self )
+		return true
+	end,
+	
+	login = function( self, username, password )
+
+		-- the http library does not yet support proxy authentication, so let's
+		-- do what's necessary here.
+	    local header = { ["Proxy-Authorization"] = "Basic " .. base64.enc(username .. ":" .. password) }
+		local response = http.generic_request(self.host, self.port, arg_method, arg_url, { header = header, bypass_cache = true } )
+		
+		-- if we didn't get a 407 error, assume the credentials
+		-- were correct. we should probably do some more checks here
+		if ( response.status ~= 407 ) then
+			return true, brute.Account:new( username, password, creds.State.VALID)
+		end
+		
+		return false, brute.Error:new( "Incorrect password" )
+	end,
+	
+	disconnect = function( self ) 
+		return true
+	end,
+}
+
+-- checks whether the proxy really needs authentication and that the
+-- authentication mechanism can be handled by our script, currently only
+-- BASIC authentication is supported.
+local function checkProxy(host, port, url)
+	local response = http.generic_request(host, port, arg_method, url, { bypass_cache = true })
+
+	if ( response.status ~= 407 ) then
+		return false, "Proxy server did not require authentication"
+	end
+
+	local proxy_auth = response.header["proxy-authenticate"]
+	if ( not(proxy_auth) ) then
+		return false, "No proxy authentication header was found"
+	end
+	
+	local challenges = http.parse_www_authenticate(proxy_auth)
+	
+	for _, challenge in ipairs(challenges) do
+		if ( "Basic" == challenge.scheme ) then
+			return true
+		end
+	end
+	return false, "The authentication scheme wasn't supported"
+end
+
+action = function(host, port)
+
+	local status, err = checkProxy(host, port, arg_url)
+	if ( not(status) ) then
+		return ("\n  ERROR: %s"):format(err)
+	end
+
+	local engine = brute.Engine:new(Driver, host, port)
+	engine.options.script_name = SCRIPT_NAME
+	status, result = engine:start()
+
+	return result
+end

scripts/script.db

@@ -119,6 +119,7 @@ Entry { filename = "http-open-proxy.nse", categories = { "default", "discovery",
 Entry { filename = "http-open-redirect.nse", categories = { "discovery", "intrusive", } }
 Entry { filename = "http-passwd.nse", categories = { "intrusive", "vuln", } }
 Entry { filename = "http-php-version.nse", categories = { "discovery", "safe", } }
+Entry { filename = "http-proxy-brute.nse", categories = { "brute", "external", "intrusive", } }
 Entry { filename = "http-put.nse", categories = { "discovery", "intrusive", } }
 Entry { filename = "http-robots.txt.nse", categories = { "default", "discovery", "safe", } }
 Entry { filename = "http-robtex-reverse-ip.nse", categories = { "discovery", "external", "safe", } }