Apple Airport WDS DoS

[Dylan Griffiths <dylang () thock com>]

    Thock.com
    Security Advisory

Problem: Apple AirPort WDS DoS
Affected devices: AirPort Extreme and Airport Express.
Severity: Denial of service.
Author: Dylan Griffiths <dylang () thock com>
Vendor Status: Fix available.

Overview:

Apple's AirPort devices are wireless access points, providing
802.11 services to network clients.  One popular configuration is the 
WDS which causes each access point to act like a physical port on a 
virtual switch, forwarding packets between two or more wired segments of 
a network.

Details:

When configured in a WDS, Apple's Airport Extreme and Express 
basestations can be made to crash when UDP port 161 is connected to, and 
then a link-state change occurs.  The software responsible for bridging 
packets between the wired and wireless sides will stop responding, and 
the entire device will lock up (the status lights will not indicate an 
error).  This occurs on both the wired and wireless interfaces of the 
device.

Vendor Response:

New firmware has been released for both devices.  Update your 
WDS-enabled networks to the latest firmware as soon as possible. Special 
thanks to John Clecak at Apple for working with me to isolate and 
correct this bug!

Airport Express 6.1.1 firmware
MacOSX: 
http://www.apple.com/support/downloads/airportexpressfirmware611formacosx.html
Windows: 
http://www.apple.com/support/downloads/airportexpressfirmware611forwindows.html

Airport Extreme 5.5.1 firmware
MacOSX: 
http://www.apple.com/support/downloads/airportextremefirmware551formacosx.html
Windows: 
http://www.apple.com/support/downloads/airportextremefirmware551forwindows.html



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