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TUCoPS :: Network Appliances :: napl5414.htm

Multiple Red-M 1050 Blue Tooth Access Point Vulnerabilities



10th Jun 2002 [SBWID-5414]
COMMAND

	Multiple Red-M 1050 Blue Tooth Access Point Vulnerabilities

SYSTEMS AFFECTED

	 Red-M 1050AP (Bluetooth Access Point)

	       1050AP boot     v01.03.16

	       1050AP loader   v02.01.26

	       1050AP software v02.00.26

PROBLEM

	In  @stake,  Inc  [http://www.atstake.com]  Security   Advisory,   Ollie
	Whitehouse [ollie@atstake.com] reported following bugs:
	

	

	 Issues: Red-M 1050 Access Point Management Web Server DoS

		 Red-M 1050 Access Point Case Insensitive Passwords

		 Red-M 1050 Access Point TFTP Server Based Password Attack

		 Red-M 1050 Access Point Management Session State Storage

		 Red-M 1050 Access Point Device Existence Broadcast

		 Red-M 1050 Access Point PPP Denial of Service

	

	

	

	 Overview

	 ========

	

	Red-M\'s (http://www.red-m.com) 1050AP (Bluetooth Access Point)  is  the
	device which exists  between  legacy  Ethernet  networks  and  Bluetooth
	1.0/1.1  compatible  devices  looking  to  obtain  IP  network   access.
	Red-M\'s device is currently the  only  device  which  supports  piconet
	(multiple Bluetooth clients to one access point).
	

	A number of vulnerabilities exist, which are outlined below, that  could
	enable an attacker on the wired or wireless side of the device to  mount
	an attack against the device in an attempt to locate the  device,  cause
	loss of administration functionality or  compromise  the  administration
	interface.
	

	

	

	 [1] Red-M 1050 Access Point Management Web Server DoS

	 ------------------------------------------------------

	

	The 1050AP device provides a web based  management  interface  to  allow
	configuration of the device. This web based  management  system  has  no
	concept of authorised or unauthorised hosts and is simply  protected  by
	a password over an unencrypted connection.
	

	There exists a vulnerability in the web server that runs on  the  1050AP
	that  potentially  allows  an  attacker  to  disable  the   web   server
	completely until the device is restarted (physically).
	

	 

	

	 [2] Red-M 1050 Access Point Case Insensitive passwords

	 ------------------------------------------------------

	

	Another existing vulnerability in the  AP  is  that  the  administration
	password is not case sensitive. This combined with  the  fact  that  the
	maximum password length is 16 chars (documented) and can  only  be  a-z,
	0-9 (@stake testing) greatly reduces the number of passwords  which  can
	be used and thus reduces cracking time.
	

	

	

	 [3] Red-M 1050 Access Point TFTP Sever Based Password Attack

	 -------------------------------------------------------------

	

	In addition, the AP provides a tftp  server  for  configuration  backups
	and firmware updates. This tftp server can not be disabled  and  can  be
	used by an attacker to crack the administration  password  using  a  UDP
	based attack. This combined with the above can provide an effective  way
	of cracking the administration  password  in  a  short  time  by  either
	dictionary or brute force methods.
	

	

	

	 [4] Red-M 1050 Access Point Management Session State Storage

	 -------------------------------------------------------------

	

	Their  exists  another  vulnerability  within  the  administration   web
	interface. When you login with the admin password to the web  interface,
	no cookie, session ID or basic authentication data are passed.  No  data
	is passed from either the client to server or server to  the  client  in
	response to maintain state of the current  session.  The  server  simply
	remembers that your IP successfully logged in until the session  expires
	and/or you click the logout button. This  method  of  maintaining  state
	suffers from a number of attacks:
	

		I) You connect to the device via a proxy; then any user who uses

		   the  same proxy can connect to the admin interface already

		   authenticated.

		II) You connect to the device via a firewall which does NAT/PAT; then,

		   as above, anyone who is NAT\'d behind the same IP can get access to

		   the admin interface.

		III) A number of other IP/Layer2 based attacks for traffic

		   redirection or forged packets are possible.

	

	This combined with  the  fact  that  when  changing  the  administration
	password, the device does not ask for the current password.  This  means
	that an Administrator can effectivly be locked out of the device  by  an
	attacker sucessfully exploiting this vulnerability.
	

	

	

	 [5] Red-M 1050 Access Point Device Existence Broadcast

	 -------------------------------------------------------

	

	The device  broadcasts  its  name  via  UDP  to  the  broadcast  address
	(255.255.255.255). So to detect a Red-M AP active on the network  simply
	listen on UDP port 8887, and every minute or so a broadcast  will  occur
	which delivers the following information: the  AP\'s  current  name,  IP
	address, netmask, serial number and aerial address.
	

	

	

	 [6] Red-M 1050 Access Point PPP Denial of Service

	 --------------------------------------------------

	

	Finally, it is possible for an attacker who is bonded to cause a  denial
	of service within the AP. Each attempt to connect  thereafter  will  not
	work,  simply  generating  an  error  of   \'Unable   to   establish   a
	connection\' within the Microsoft dial-up connection dialog box.
	

	

	

	

	 Details

	 =======

	

	It should be noted that although  a  number  of  issues  are  listed  as
	DoS-only, this is only limited by the fact that  during  the  assessment
	of the device  @stake  was  unable  to  gain  access  to  the  debugging
	interface to enable the successfull exploitation of the  vulnerabilities
	(be they buffer or heap overflows).
	

	 

	 [1] Red-M 1050 Access Point Management Web Server DoS

	 -----------------------------------------------------

	

	Connect  to  the  web  interface  and  enter  a  long  string  for   the
	administration password. Click \'OK\'. You will get a connect  error  on
	the page refresh and the web server will be dead until  you  power  down
	the device and restart it physically.
	

	 

	 

	[2] Red-M 1050 Access Point Case Insensitive passwords
	 ------------------------------------------------------

	

	The same file was requested twice using the  different  cases.  In  each
	case the same file was returned. This can also  be  demonstrated  within
	the web interface by attempting to log-in with either the real  password
	or a the same password but using a different case (e.g.  AbCdEf  instead
	of abcdef).
	

	

		C:\\>tftp -i 192.168.1.253 get FLASH_Database-abcdef

		Transfer successful: 381 bytes in 2 seconds, 190 bytes/s

	

		C:\\>tftp -i 192.168.1.253 get FLASH_Database-AbCdEf FLASH_Second

		Transfer successful: 381 bytes in 3 seconds, 127 bytes/s

	

		C:\\>fc FLASH_Database-abcdef FLASH_Second

		Comparing files FLASH_Database-abcdef and FLASG_Second

		FC: no differences encountered

	<§font>

	

	

	

	 [3] Red-M 1050 Access Point TFTP Sever Based Password Attack

	 -------------------------------------------------------------

	

	Simply execute the following command replacing the <password> tag with the

	attempted password.

	

	

		tftp -i 192.168.1.1 get FLASH_Database-<password>

	

	

	

	

	 [4] Red-M 1050 Access Point Management Session State Storage

	 ------------------------------------------------------------

	

	A simple way to demonstrate this vulnerability is  to  use  one  browser
	(such as IE) and authenticate with the management interface.  Then  load
	a different browser (such as Netscape) and then type in the  address  of
	the AP. You will be presented with the pre-authenticated  administrative
	interface on the AP.
	

	

	

	 [5] Red-M 1050 Access Point Device Existence Broadcast

	 -------------------------------------------------------

	

	Use a tool such as netcat to listen on port UDP/8887 (i.e. nc -u  -L  -p
	8887
	 -o output). Every 30 seconds a new entry will be made in the log file similar

	to the one below:
	

	

	< 00000000 2c 01 be ba c0 a8 01 fd ff ff ff 00 00 02 81 64 # &....2.........d

	< 00000010 00 56 02 06 08 01 00 00 00 0d 01 57 6f 6c 6c 79 # .V.........Wolly

	< 00000020 57 6f 72 6c 64 00                               # World.

	

	

	A break down of the packet is as follows:
	

	

		[bytes 1]               Length of data segment of packet

		[bytes 2 to 4]          Unknown

		[bytes 5 to 8]          IP address of device

		[bytes 9 to 12]         Subnet mask of device

		[bytes 13 to 15]        Serial Number*

		[bytes 16 to 18]        Bluetooth Address*

		[byte  19]              Is the device configured (01 = no / 02 = yes)

		[bytes 20 to 27]        Unknown

		[bytes 28 to LEN-1]     Access point name

	

	

	The above packet is how Red-M\'s own set up program knows of  the  AP\'s
	existence on the network.
	

	* [bytes 13 to 18] the aerial address
	

	

	

	 [6] Red-M 1050 Access Point PPP Denial of Service

	 --------------------------------------------------

	

	Bond and then connect with the AP. When prompted for  the  PPP  username
	for the link enter a very long username.

SOLUTION

	Upgrade your firmware to the latest  release.  In  addition  follow  the
	steps outlined below to mitigate the current design vulnerabilities.
	

	Typically, wireless access points to the network  should  be  considered
	hostile networks. In the case of  the  above  vulnerabilities  a  packet
	filtering device should be placed between the Ethernet interface of  the
	AP and the corporate network restricting the types of traffic  and  from
	which hosts communication destined for the AP  can  come  from.  However
	this will still expose the device to attacks from the wireless  side  of
	the device. To guard against these attacks, ensure  that  good  username
	and password policies are in place. However,  consider  the  limitations
	of the username and passwords in the 1050AP. Strong  passwords  may  not
	be possible. From @stake\'s testing, usernames and  passwords  can  only
	be [a-z] and [0-9] within the device\'s PPP authentication mechanism.
	

	The 1050AP does provide a number of other mechanisms to protect  against
	being discovered and  to  protect  against  automatic  connections.  For
	details of these please refer to  the  vendor\'s  documentation.  It  is
	@stake\'s recommendation that the following options are used:
	

	

		[Option]                        [Suggested Setting]

		Authentication:                 Authentication with bonding

		Force encryption:               Check box

		Accessibility mode:             Connectable and non discoverable

		PPP authentication:             Check box

		Automatically authorize:        Uncheck box

	


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