description = [[
Looks for signature of known server compromises. Currently, the only signature it looks for is
the one discussed here:
<http://blog.unmaskparasites.com/2009/09/11/dynamic-dns-and-botnet-of-zombie-web-servers/>

This is done by requesting the page /ts/in.cgi?open2 and looking for an errant 302 (it attempts 
to detect srevers that always return 302). 

Thanks to Denis from the above link for finding this technique! 
]]

---
--@output
-- Interesting ports on www.sopharma.bg (84.242.167.49):
-- PORT     STATE SERVICE    REASON
-- 80/tcp   open  http       syn-ack
-- |_ http-infected: Host appears to be clean
-- 8080/tcp open  http-proxy syn-ack
-- |  http-malware-host: Host appears to be infected (/ts/in.cgi?open2 redirects to http://last-another-life.ru:8080/index.php)
-- |_ See: http://blog.unmaskparasites.com/2009/09/11/dynamic-dns-and-botnet-of-zombie-web-servers/
-- 

author = "Ron Bowes <ron@skullsecurity.net>"

license = "Same as Nmap--See http://nmap.org/book/man-legal.html"

categories = {"malware", "safe"}

require 'stdnse'
require 'http'
require 'stdnse'

portrule = function(host, port)
	local svc = { std = { ["http"] = 1, ["http-alt"] = 1, ["http-proxy"] = 1 },
				ssl = { ["https"] = 1, ["https-alt"] = 1 } }
	if port.protocol ~= 'tcp'
	or not ( svc.std[port.service] or svc.ssl[port.service] ) then
		return false
	end
	-- Don't bother running on SSL ports if we don't have SSL.
	if (svc.ssl[port.service] or port.version.service_tunnel == 'ssl')
	and not nmap.have_ssl() then
		return false
	end
	return true
end

local function go(host, port)
	-- Check what response we get for a 404
	local result, result_404, known_404 = http.identify_404(host, port)
	if(result == false) then
		return false, "Couldn't identify 404 message: " .. result_404
	end

	-- If the 404 result is a 302, we're going to have trouble
	if(result_404 == 302) then
		return false, "Unknown pages return a 302 response; unable to check"
	end

	-- Perform a GET request on the file
	result = http.get_url("http://" .. host.ip .. ":" .. port.number .. "/ts/in.cgi?open2")
	if(result == nil) then
		return false, "Couldn't perform GET request"
	end

	if(result.status == 302) then
		if(result.header.location) then
			return true, string.format("Host appears to be infected (/ts/in.cgi?open2 redirects to %s)\nSee: http://blog.unmaskparasites.com/2009/09/11/dynamic-dns-and-botnet-of-zombie-web-servers/", result.header.location)
		else
			return true, string.format("Host appears to be infected (/ts/in.cgi?open2 return a redirect)\nSee: http://blog.unmaskparasites.com/2009/09/11/dynamic-dns-and-botnet-of-zombie-web-servers/")
		end
	end

	return true, nil
end

action = function(host, port)
	local status, result = go(host, port)

	if(status == false) then
		if(nmap.debugging() > 0) then
			return "ERROR: " .. result
		else
			return nil
		end
	end

	return result
end