Every BigPond Speedtouch router WiFi password vulnerable

David M Williams
Wednesday, 06 January 2010 03:39

Business IT - Security

A big pong may be set to erupt over an incredibly serious WiFi router password vulnerability baked into all BigPond Thomson Speedtouch routers.

The average residential consumer uses the Internet gateway device supplied by their ISP. In the case of BigPond this has long been the Thomson Speedtouch range. The unit comes with a card listing the cryptic WiFi WPA security password but this is easily cracked by information given in the SSID.

Home WiFi networking has exploded in popularity and prominence in the last five years. Early devices were completely open, allowing the user to specify a Service Set Identifier (SSID) as well as the means of encrypting data as it flowed over the air, along with necessary passwords.

Yet, many consumers, used to the plug-in-and-it-works method of most whitegoods and consumer entertainment devices, did not take any steps to secure the WiFi emanating about their household.

This led to much wailing and gnashing of teeth when neighbours discovered they could leech off each other’s Internet, especially so in dense residential areas.

Realising the average consumer needed help in securing their own connection certain ISPs and hardware vendors took steps to pre-secure the devices being deployed.

In the case of BigPond, the Thomson Speedtouch – whether installed by a Telstra technician or purchased in-store in the form of a self-installation kit – gives the illusion of security through a device-specific SSID and WPA key.

This information is printed on a plastic credit-card sized reminder which also states, “This card contains the Wi-Fi network security details for your ADSL gateway. You should keep this card in a safe and secure place.”

Consequently, the average punter sees their device as secure, with a cryptic WPA key to match. They can plug it in and forget about it, pulling out this card only if they happen to connect another computer to their network.

Yet, it turns out the BigPond device is only marginally more secure than if it had no encryption at all, because the information given in the publicly-viewable SSID can be used to determine the WPA password.

This is because the SSID name (eg BigPondCAD097) contains hexadecimal digits which are hashed from the unit’s serial number. The WPA key is also hashed from the serial number. That is, two key pieces of data are both derived from the one initial key value – and one of those two pieces, the SSID, is public.

It thus becomes a matter of time to deduce likely candidates for the WPA password based on the hex digits in the SSID.

In fact, the more hex digits listed in the SSID – in BigPond’s case, six – the easier it is to home in on the WPA password. Six hex digits is enough information to calculate a mere two possible passwords. Try one, if it doesn’t work, try the other.

Had the number of hex digits been four instead of six then an average of 80 possible keys would need to be tested, and this number increasing as the amount of hex digits given away for free reduces.

If you wish to test this for yourself on your own BigPond network please read on.