Researchers find more flaws in wireless security
Wireless networks that use a popular form of security known as Wi-Fi Protected Access (WPA) are vulnerable to an attack that could compromise certain communications in less than 15 minutes, two researchers plan to tell attendees next week at the PacSec 2008 conference in Tokyo.
Martin Beck and Erik Tews - two graduate students at technical universities in Germany - found a combination of techniques that allow an attacker to decrypt limited communications protected with the lesser of two WPA security protocols, known as the Temporal Key Integrity Protocol or TKIP. Using the techniques, attackers could also recover a special integrity checksum and send up to seven custom packets to clients on the network, sources told SecurityFocus.
The attack does not allow the key protecting the communications to be recovered, one of the researchers stressed .
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While the security vulnerabilities are limited, the techniques could be used in a denial-of-service (DoS) attack, the researchers stated in their presentation, by using ARP injection to overwrite entries in the ARP table or potentially attack a local network's domain servers. The technique could also be used to channel data through a corporate firewall, they added.
In an email to a security mailing list, PacSec conference organizer Dragos Ruiu recommended that wireless-network administrators move to WPA2 or use the improved WPA security mode, known as Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP). In the latter case, the access point should not allow clients to revert to TKIP for communications with legacy systems, Ruiu said.
"If you aren't given the option to disable this, you might want to think about getting a different Access Point or Wi-Fi Router," he said.
According to Tews, an experimental implementation of the researchers' attack has been introduced into a development version of the aircrack-ng tool.
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