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39 lines
1.2 KiB
Lua
39 lines
1.2 KiB
Lua
id = "Nameserver open recursive querys (CVE-1999-0024) (BID 136, 678)"
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description = "Checks whether a Nameserver on udp/53 allows querys for third-party names. If is expected that recursion will be enabled on your own internal nameserver."
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author = "Felix Groebert <felix@groebert.org>"
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license = "Same as Nmap--See http://nmap.org/man/man-legal.html"
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categories = {"intrusive"}
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require "bit"
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require "shortport"
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portrule = shortport.portnumber(53, "udp")
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action = function(host, port)
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-- generate dns query, Transaction-ID 0xdead, isc.sans.org (type A, class IN)
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local request = string.char(0xde, 0xad, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03) .. "isc" .. string.char(0x04) .. "sans" .. string.char(0x03) .. "org" .. string.char(0x00, 0x00, 0x01, 0x00, 0x01)
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local socket = nmap.new_socket()
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socket:connect(host.ip, port.number, "udp")
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socket:send(request)
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local status, result = socket:receive();
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socket:close()
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-- parse response for dns flags
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if (bit.band(string.byte(result,3), 0x80) == 0x80
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and bit.band(string.byte(result,4), 0x85) == 0x80)
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then
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return "Recursion seems enabled"
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else
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return "Recursion not enabled"
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end
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return
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end
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