local io = require "io" local nmap = require "nmap" local shortport = require "shortport" local stdnse = require "stdnse" local sslcert = require "sslcert" local tls = require "tls" description = [[ Checks whether the SSL certificate used by a host has a fingerprint that matches an included database of problematic keys. The only databases currently checked are the LittleBlackBox 0.1 database of compromised keys from various devices, some keys reportedly used by the Chinese state-sponsored hacking division APT1 (https://www.fireeye.com/blog/threat-research/2013/03/md5-sha1.html), and the key used by CARBANAK malware (https://www.fireeye.com/blog/threat-research/2017/06/behind-the-carbanak-backdoor.html). However, any file of fingerprints will serve just as well. For example, this could be used to find weak Debian OpenSSL keys using the widely available (but too large to include with Nmap) list. ]] --- -- @usage -- nmap --script ssl-known-key -p 443 -- -- @args ssl-known-key.fingerprintfile Specify a different file to read -- fingerprints from. -- -- @output -- PORT STATE SERVICE REASON -- 443/tcp open https syn-ack -- |_ssl-known-key: Found in Little Black Box 0.1 (SHA-1: 0028 e7d4 9cfa 4aa5 984f e497 eb73 4856 0787 e496) -- -- @xmloutput -- -- Little Black Box 0.1 -- 0028e7d49cfa4aa5984fe497eb7348560787e496 --
author = "Mak Kolybabi" license = "Same as Nmap--See https://nmap.org/book/man-legal.html" categories = {"safe", "discovery", "vuln", "default"} dependencies = {"https-redirect"} local FINGERPRINT_FILE = "ssl-fingerprints" local get_fingerprints = function(path) -- Check registry for cached fingerprints. if nmap.registry.ssl_fingerprints then stdnse.debug2("Using cached SSL fingerprints.") return true, nmap.registry.ssl_fingerprints end -- Attempt to resolve path if it is relative. local full_path = nmap.fetchfile("nselib/data/" .. path) if not full_path then full_path = path end stdnse.debug2("Loading SSL fingerprints from %s.", full_path) -- Open database. local file = io.open(full_path, "r") if not file then return false, "Failed to open file " .. full_path end -- Parse database. local section = nil local fingerprints = {} for line in file:lines() do line = line:gsub("#.*", "") line = line:gsub("^%s*", "") line = line:gsub("%s*$", "") if line ~= "" then if line:sub(1,1) == "[" then -- Start a new section. line = line:sub(2, #line - 1) stdnse.debug4("Starting new section %s.", line) section = line elseif section ~= nil then -- Add fingerprint to section. local fingerprint = stdnse.fromhex(line) if #fingerprint == 20 then fingerprints[fingerprint] = section stdnse.debug4("Added key %s to database.", line) else stdnse.debug0("Cannot parse presumed fingerprint %q in section %q.", line, section) end else -- Key found outside of section. stdnse.debug1("Key %s is not in a section.", line) end end end -- Close database. file:close() -- Cache fingerprints in registry for future runs. nmap.registry.ssl_fingerprints = fingerprints return true, fingerprints end portrule = function(host, port) return shortport.ssl(host, port) or sslcert.isPortSupported(port) or sslcert.getPrepareTLSWithoutReconnect(port) end action = function(host, port) -- Get script arguments. host.targetname = tls.servername(host) local path = stdnse.get_script_args("ssl-known-key.fingerprintfile") or FINGERPRINT_FILE local status, result = get_fingerprints(path) if not status then stdnse.debug1("%s", result) return end local fingerprints = result -- Get SSL certificate. local status, cert = sslcert.getCertificate(host, port) if not status then stdnse.debug1("sslcert.getCertificate error: %s", cert) return end local fingerprint = cert:digest("sha1") local fingerprint_fmt = stdnse.tohex(fingerprint, {separator=" ", group=4}) -- Check SSL fingerprint against database. local section = fingerprints[fingerprint] if not section then stdnse.debug2("%s was not in the database.", fingerprint_fmt) return end return {section=section, sha1=stdnse.tohex(fingerprint)}, "Found in " .. section .. " (SHA-1: " .. fingerprint_fmt .. ")" end