29.10.09

WPA is next to death!

Last November, German researches found the first vulnerability in WPA/TKIP, which allows the attacker to break some short packets with most fields known, e.g. ARP request/response, within 12-15 minutes, and inject up to 7 packets.

Two months earlier, Japanese researchers improved the attack:
In 2008, Beck and Tews have proposed a practical attack on WPA. Their attack (called the Beck-Tews attack) can recover plaintext from an encrypted short packet, and can falsify it. The execution time of the Beck-Tews attack is about 12-15 minutes. However, the attack has the limitation, namely, the targets are only WPA implementations those support IEEE802.11e QoS features. In this paper, we propose a practical message falsification attack on any WPA implementation. In order to ease targets of limitation of wireless LAN products, we apply the Beck-Tews attack to the man-in-the-middle attack. In the man-in-the-middle attack, the user’s communication is intercepted by an attacker until the attack ends. It means that the users may detect our attack when the execution time of the attack is large. Therefore, we give methods for reducing the execution time of the attack. As a result, the execution time of our attack becomes about one minute in the best case.

Now, Halvorsen with others made another progress, enabling hackers to inject a huge number of malicious bytes within approximately 18 minutes and 25 seconds:
Beck and Tews described the first practical cryptographic attack on IEEE 802.11i TKIP in November 2008, and this paper continues this line of protocol cryptanalysis. We show that their attack on TKIP can be used to create an ARP poisoning attack and a cryptographic DoS attack. Moreover, we are able to decrypt DHCP ACK packets, which are over 12 times longer than the ARP packet used by Beck and Tews. Our method of analysis recovers 596 bytes of keystream that can be used in new attacks on other control protocol messages.

We should remember that the attacks would always improve. Therefore, switch your network to WPA2/CCMP right now!