svn-brute NSE Script

2010-08-18T20:50:51
ID NMAP:SVN-BRUTE.NSE
Type nmap
Reporter Patrik Karlsson
Modified 2018-10-18T01:08:19

Description

Performs brute force password auditing against Subversion source code control servers.

Script Arguments

svn-brute.repo

the Subversion repository against which to perform password guessing

svn-brute.force

force password guessing when service is accessible both anonymously and through authentication

brute.credfile, brute.delay, brute.emptypass, brute.firstonly, brute.guesses, brute.mode, brute.passonly, brute.retries, brute.start, brute.threads, brute.unique, brute.useraspass

See the documentation for the brute library.

creds.[service], creds.global

See the documentation for the creds library.

passdb, unpwdb.passlimit, unpwdb.timelimit, unpwdb.userlimit, userdb

See the documentation for the unpwdb library.

Example Usage

nmap --script svn-brute --script-args svn-brute.repo=/svn/ -p 3690 <host>

Script Output

PORT     STATE SERVICE REASON
3690/tcp open  svn     syn-ack
| svn-brute:
|   Accounts
|_    patrik:secret => Login correct

Summary
-------
  x The svn class contains the code needed to perform CRAM-MD5
    authentication
  x The Driver class contains the driver implementation used by the brute
    library

Requires

  • brute
  • creds
  • nmap
  • shortport
  • stdnse
  • stringaux
  • openssl

                                        
                                            local brute = require "brute"
local creds = require "creds"
local nmap = require "nmap"
local shortport = require "shortport"
local stdnse = require "stdnse"
local stringaux = require "stringaux"
local openssl = stdnse.silent_require "openssl"

description = [[
Performs brute force password auditing against Subversion source code control servers.
]]

---
-- @usage
-- nmap --script svn-brute --script-args svn-brute.repo=/svn/ -p 3690 <host>
--
-- @output
-- PORT     STATE SERVICE REASON
-- 3690/tcp open  svn     syn-ack
-- | svn-brute:
-- |   Accounts
-- |_    patrik:secret => Login correct
--
-- Summary
-- -------
--   x The svn class contains the code needed to perform CRAM-MD5
--     authentication
--   x The Driver class contains the driver implementation used by the brute
--     library
--
-- @args svn-brute.repo the Subversion repository against which to perform
--                      password guessing
-- @args svn-brute.force force password guessing when service is accessible
--       both anonymously and through authentication

--
-- Version 0.1
-- Created 07/12/2010 - v0.1 - created by Patrik Karlsson <patrik@cqure.net>
--


author = "Patrik Karlsson"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"intrusive", "brute"}

portrule = shortport.port_or_service(3690, "svnserve", "tcp", "open")

svn =
{
  svn_client = "nmap-brute v0.1",

  new = function(self, host, port, repo)
    local o = {}
    setmetatable(o, self)
    self.__index = self
    o.host = host
    o.port = port
    o.repo = repo
    o.invalid_users = {}
    return o
  end,

  --- Connects to the SVN - repository
  --
  -- @return status true on success, false on failure
  -- @return err string containing an error message on failure
  connect = function(self)
    local repo_url = ( "svn://%s/%s" ):format(self.host.ip, self.repo)
    local status, msg

    self.socket = brute.new_socket()

    local result
    status, result = self.socket:connect(self.host, self.port)
    if( not(status) ) then
      return false, result
    end

    status, msg = self.socket:receive_bytes(1)
    if ( not(status) or not( msg:match("^%( success") ) ) then
      return false, "Banner reports failure"
    end

    msg = ("( 2 ( edit-pipeline svndiff1 absent-entries depth mergeinfo log-revprops ) %d:%s %d:%s ( ) ) "):format( #repo_url, repo_url, #self.svn_client, self.svn_client )
    status = self.socket:send( msg )
    if ( not(status) ) then
      return false, "Send failed"
    end

    status, msg = self.socket:receive_bytes(1)
    if ( not(status) ) then
      return false, "Receive failed"
    end

    if ( msg:match("%( success") ) then
      local tmp = msg:match("%( success %( %( ([%S+%s*]-) %)")
      if ( not(tmp) ) then return false, "Failed to detect authentication" end
      tmp = stringaux.strsplit(" ", tmp)
      self.auth_mech = {}
      for _, v in pairs(tmp) do self.auth_mech[v] = true end
    elseif ( msg:match("%( failure") ) then
      return false
    end

    return true
  end,

  --- Attempts to login to the SVN server
  --
  -- @param username string containing the login username
  -- @param password string containing the login password
  -- @return status, true on success, false on failure
  -- @return err string containing error message on failure
  login = function( self, username, password )
    local status, msg
    local challenge, digest

    if ( self.auth_mech["CRAM-MD5"] ) then
      msg = "( CRAM-MD5 ( ) ) "
      status = self.socket:send( msg )

      status, msg = self.socket:receive_bytes(1)
      if ( not(status) ) then
        return false, "error"
      end

      challenge = msg:match("<.+>")

      if ( not(challenge) ) then
        return false, "Failed to read challenge"
      end

      digest = stdnse.tohex(openssl.hmac('md5', password, challenge))
      msg = ("%d:%s %s "):format(#username + 1 + #digest, username, digest)
      self.socket:send( msg )

      status, msg = self.socket:receive_bytes(1)
      if ( not(status) ) then
        return false, "error"
      end

      if ( msg:match("Username not found") ) then
        return false, "Username not found"
      elseif ( msg:match("success") ) then
        return true, "Authentication success"
      else
        return false, "Authentication failed"
      end
    else
      return false, "Unsupported auth-mechanism"
    end

  end,

  --- Close the SVN connection
  --
  -- @return status true on success, false on failure
  close = function(self)
    return self.socket:close()
  end,

}


Driver =
{
  new = function(self, host, port, invalid_users )
    local o = {}
    setmetatable(o, self)
    self.__index = self
    o.host = host
    o.port = port
    o.repo = stdnse.get_script_args('svn-brute.repo')
    o.invalid_users = invalid_users
    return o
  end,

  connect = function( self )
    local status, msg

    self.svn = svn:new( self.host, self.port, self.repo )
    status, msg = self.svn:connect()
    if ( not(status) ) then
      local err = brute.Error:new( "Failed to connect to SVN server" )
      -- This might be temporary, set the retry flag
      err:setRetry( true )
      return false, err
    end

    return true
  end,

  disconnect = function( self )
    self.svn:close()
  end,

  --- Attempts to login to the SVN server
  --
  -- @param username string containing the login username
  -- @param password string containing the login password
  -- @return status, true on success, false on failure
  -- @return brute.Error object on failure
  --         creds.Account object on success
  login = function( self, username, password )
    local status, msg

    if ( self.invalid_users[username] ) then
      return false, brute.Error:new( "User is invalid" )
    end

    status, msg = self.svn:login( username, password )

    if ( not(status) and msg:match("Username not found") ) then
      self.invalid_users[username] = true
      return false, brute.Error:new("Username not found")
    elseif ( status and msg:match("success") ) then
      return true, creds.Account:new(username, password, creds.State.VALID)
    else
      return false, brute.Error:new( "Incorrect password" )
    end
  end,

  --- Verifies whether the repository is valid
  --
  -- @return status, true on success, false on failure
  -- @return err string containing an error message on failure
  check = function( self )
    local svn = svn:new( self.host, self.port, self.repo )
    local status = svn:connect()

    svn:close()

    if ( status ) then
      return true
    else
      return false, ("Failed to connect to SVN repository (%s)"):format(self.repo)
    end
  end,
}



action = function(host, port)
  local status, accounts

  local repo = stdnse.get_script_args('svn-brute.repo')
  local force = stdnse.get_script_args('svn-brute.force')

  if ( not(repo) ) then
    return "No repository specified (see svn-brute.repo)"
  end

  local svn = svn:new( host, port, repo )
  local status = svn:connect()

  if ( status and svn.auth_mech["ANONYMOUS"] and not(force) ) then
    return "  \n  Anonymous SVN detected, no authentication needed"
  end

  if ( not(svn.auth_mech) or not( svn.auth_mech["CRAM-MD5"] ) ) then
    return "  \n  No supported authentication mechanisms detected"
  end

  local invalid_users = {}
  local engine = brute.Engine:new(Driver, host, port, invalid_users)
  engine.options.script_name = SCRIPT_NAME
  status, accounts = engine:start()
  if( not(status) ) then
    return accounts
  end

  return accounts
end