Say Goodbye to WEP and TKIP

19 JUNI 2010

By Glenn Fleishman

The Wi-Fi Alliance has a timetable for eliminating outdated WEP and TKIP security from certified Wi-Fi devices: A couple of news sites ran unsourced stories yesterday and today about a roadmap from the Wi-Fi Alliance for eliminating older encryption methods from the certification process for new hardware.

I picked up the phone (yes, crazy, I know!), and confirmed it: TKIP and WEP won't be allowed in new devices with the Wi-Fi stamp in a staged elimination over three years starting in 2011.

Anyone reading this site should be well aware that WEP (Wired Equivalent Privacy), the original local-link encryption standard in 802.11b, has been broken since 2001, and horribly so since 2003.

TKIP (Temporal Key Integrity Protocol) was a backwards compatible replacement introduced in 2003, and intended to work with older silicon that didn't have either the circuits or computational muster to handle WEP's real replacement, AES-CCMP (you don't want to know what that stands for, honestly). AES (also from 2003) is often called WPA2 encryption, although it's more particularly an encryption type that's part of WPA2.

While TKIP hasn't been broken, it has known vulnerabilities, such as a susceptibility to dictionary-based attacks for short keys (eight characters), and some very clever ways to insert packets through manipulating a flaw in the packet integrity protocol. (See my 2008 Ars Technica article, "Battered, but not broken: understanding the WPA crack," and my article on this site, "Another, Better TKIP Attack That's Still Limited" from Feb. 2010. It's likely more will be found.)

The 802.11n standard only allows the use of AES keys, which sometimes provokes confusing statements about its capabilities. Apple updated a support note on 3 June 2010 which stated that 802.11n with WEP or TKIP could only operate at 54 Mbps, when it's perhaps more accurate to state that 802.11n drops down to 802.11g to handle these older security types.

Kelly Davis-Felner, the Wi-Fi Alliance's marketing director, said, "We had a process within our membership to say we have a few aging security mechanisms, one of which is known to be obsolete - and that would be WEP, of course - and we wanted to define what the roadmap would look like to get the whole industry to end of life" the technology.

The Wi-Fi Alliance is a membership trade group that sets certification standards for products that bear the Wi-Fi seal. As such, its efforts are driven by what the members want, and the group allows a typically consistent approach across the entire industry.

The alliance's product manager for putting WEP and TKIP out of their misery, Sarah Morris, said that TKIP and WEP will be phased out in stages starting 1 January 2011 until 1 January 2014. Changes affect only new devices seeking certification. Companies can also release 802.11 equipment without the Wi-Fi imprimatur, although that's extremely rare, and essentially unheard of among any major equipment maker.

At the start of 2011, access points will no longer be certified with TKIP as an option by itself, commonly revealed as WPA-PSK, WPA-TKIP, or WPA Personal. Mixed modes, in which an AP can accept either TKIP or AES keys, will still be allowed.

But also starting in 2011, manufacturers can opt to ship Wi-Fi hardware preset to use WPA2 out of the box. Currently, Wi-Fi-certified access points have to be set to open, and a purchaser configures it to use security. This is an interesting change, and part of what Davis-Felner said will be greater efforts in the coming year to promote security.

In 2012, new Wi-Fi adapters (so-called stations in 802.11 parlance) won't be allowed to support TKIP.

In 2013, WEP is finally disallowed for APs. While that seems incredibly late, its inclusion is there only for certain categories of legacy devices for which no other option is available. WEP is used by point of sale systems and older hardware that can't be upgraded. It's perhaps too kind to leave it as an option for that long, but it's also a membership decision, so clearly justified by a remaining installed base.

In 2014, the mixed TKIP/AES mode for access points can no longer be included in certified devices, and WEP cannot be available to new client devices.

The move to an all-AES world is long in coming. "You've heard us say for a long, long time that WPA2 is the recommended configuration for any Wi-Fi network or enterprise," said Davis-Felner. "This is a strong expression of that position."

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