tor-consensus-checker
NSE detection rule by Jiayi Ye · Same as Nmap--See https://nmap.org/book/man-legal.html
Checks if a target is a known Tor node.
The script works by querying the Tor directory authorities. Initially,
the script stores all IPs of Tor nodes in a lookup table to reduce the
number of requests and make lookups quicker.
local http = require "http"
local ipOps = require "ipOps"
local stdnse = require "stdnse"
local string = require "string"
local nmap = require "nmap"
description = [[
Checks if a target is a known Tor node.
The script works by querying the Tor directory authorities. Initially,
the script stores all IPs of Tor nodes in a lookup table to reduce the
number of requests and make lookups quicker.
]]
---
-- @usage
-- nmap --script=tor-consensus-checker <host>
--
-- @output
-- Host script results:
-- | tor-consensus-checker:
-- |_ 127.0.0.1 is a Tor node
---
author = "Jiayi Ye"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"external", "safe"}
-- from Tor 0.2.9 auth_dirs.inc
local dir_authorities = {
{ ip = "128.31.0.39", port = 9131},
{ ip = "86.59.21.38", port = 80 },
{ ip = "45.66.33.45", port = 80 },
{ ip = "66.111.2.131", port = 9030 },
{ ip = "131.188.40.189", port = 80 },
{ ip = "193.23.244.244", port = 80 },
{ ip = "171.25.193.9", port = 443 },
{ ip = "154.35.175.225", port = 80 },
{ ip = "199.58.81.140", port = 80 },
{ ip = "204.13.164.118", port = 80 },
}
hostrule = function(host)
if nmap.registry.tornode and not(nmap.registry.tornode.connect) then
return false
end
return not ipOps.isPrivate(host.ip)
end
function get_consensus(server)
local response = http.get(server.ip, server.port, "/tor/status-vote/current/consensus",
{
-- consensus files were 2.3 MiB as of February 2020
-- https://metrics.torproject.org/collector/recent/relay-descriptors/consensuses/
no_cache = true,
max_body_size=3*1024*1024
})
if not response.status then
stdnse.print_debug(2, "failed to connect to " .. server.ip)
elseif response.status ~= 200 then
stdnse.print_debug(2, "%s http error %s", server.ip, response.status)
else
stdnse.print_debug(2, "consensus retrieved from %s", server.ip)
return response.body
end
-- no valid server found
return nil
end
function script_init()
-- Data and flags shared between threads.
-- @name tornode
-- @class table
-- @field cache A table for cached tor nodes
-- @field connect A flag which prevents threads from looking up when failed to connnect to directory authorities
nmap.registry.tornode = {}
nmap.registry.tornode.cache = {}
local isConnected = false
local regexp = "r [%S]+ [%S]+ [%S]+ [%d-]+ [%d:]+ ([%d.]+) ([%d]+) [%d]*"
for _, server in ipairs(dir_authorities) do
local consensus = get_consensus(server)
if consensus then
-- parse the consensus
for line in string.gmatch(consensus,"[^\n]+") do
local _, _, ip, port = string.find(line,regexp)
if ip then
isConnected = true
nmap.registry.tornode.cache[ip] = true
end
end
end
if isConnected then
break
end
end
if not(isConnected) then
stdnse.verbose1("failed to connect to directory authorities")
end
nmap.registry.tornode.connect = isConnected
end
function check_tornode_cache(ip)
if not next( nmap.registry.tornode.cache ) then return false end
if type( ip ) ~= "string" or ip == "" then return false end
return nmap.registry.tornode.cache[ip]
end
action = function(host)
local mutex = nmap.mutex("tornode")
mutex "lock"
--initialize nmap.registry.tornode
if not nmap.registry.tornode then
script_init()
end
mutex "done"
if not(nmap.registry.tornode.connect) then
if nmap.verbosity() > 2 then
return "Couln't connect to Tor dir authorities"
else
return nil
end
end
local output_tab = stdnse.output_table()
if check_tornode_cache(host.ip) then
output_tab.tor_nodes = host.ip
return output_tab, host.ip .. " is a Tor node"
else
return output_tab, host.ip .. " not found in Tor consensus"
end
end