Merged gsoc-ssh branch. Closes #910

scripts/ssh-brute.nse

@@ -0,0 +1,114 @@
+local shortport = require "shortport"
+local stdnse = require "stdnse"
+local brute = require "brute"
+local creds = require "creds"
+
+local libssh2_util = require "libssh2-utility"
+
+description = [[
+Performs brute-force password guessing against ssh servers.
+]]
+
+---
+-- @usage
+--   nmap -p 22 --script ssh-brute --script-args userdb=users.lst,passdb=pass.lst \
+--       --script-args ssh-brute.timeout=4s <target>
+--
+-- @output
+-- 22/ssh open  ssh
+-- | ssh-brute:
+-- |  Accounts
+-- |    username:password
+-- |  Statistics
+-- |_   Performed 32 guesses in 25 seconds.
+--
+-- @args ssh-brute.timeout    Connection timeout (default: "5s")
+
+author = "Devin Bjelland"
+license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
+categories = {
+  'brute',
+  'intrusive',
+}
+
+portrule = shortport.port_or_service(22, 'ssh')
+
+local arg_timeout = stdnse.get_script_args(SCRIPT_NAME .. ".timeout") or "5s"
+
+Driver = {
+  new = function (self, host, port, options)
+    stdnse.debug(2, "creating brute driver")
+    local o = {
+      helper = libssh2_util.SSHConnection:new(),
+    }
+    setmetatable(o, self)
+    self.__index = self
+    o.host = host
+    o.port = port
+    o.options = options
+    return o
+  end,
+
+  connect = function (self)
+    local status, err = self.helper:connect_pcall(self.host, self.port)
+    if not status then
+      stdnse.debug(2, "libssh2 error: %s", self.helper.session)
+      local err = brute.Error:new(self.helper.session)
+      err:setReduce(true)
+      return false, err
+    elseif not self.helper.session then
+      stdnse.debug(2, "failure to connect: %s", err)
+      local err = brute.Error:new(err)
+      err:setAbort(true)
+      return false, err
+    else
+      self.helper:set_timeout(self.options.ssh_timeout)
+      return true
+    end
+  end,
+
+  login = function (self, username, password)
+    stdnse.verbose(1, "Trying username/password pair: %s:%s", username, password)
+    local status, resp = self.helper:password_auth(username, password)
+    if status then
+      return true, creds.Account:new(username, password, creds.State.VALID)
+    end
+    return false, brute.Error:new "Incorrect password"
+  end,
+
+  disconnect = function (self)
+    return self.helper:disconnect()
+  end,
+}
+
+local function password_auth_allowed (host, port)
+  local helper = libssh2_util.SSHConnection:new()
+  if not helper:connect(host, port) then
+    return "Failed to connect to ssh server"
+  end
+  local methods = helper:list "root"
+  if methods then
+    for _, value in pairs(methods) do
+      if value == "password" then
+        return true
+      end
+    end
+  end
+  return false
+end
+
+function action (host, port)
+  local timems = stdnse.parse_timespec(arg_timeout) --todo: use this!
+  local ssh_timeout = 1000 * timems
+  if password_auth_allowed(host, port) then
+    local options = {
+      ssh_timeout = ssh_timeout,
+    }
+    local engine = brute.Engine:new(Driver, host, port, options)
+    engine.options.script_name = SCRIPT_NAME
+    local _, result = engine:start()
+    return result
+  else
+    return "Password authenication not allowed"
+  end
+end