WEP is notoriously bad. We set out to find out just how bad.

The most egregious issue with WEP is its lack of key management. You pick an encryption key, give it to your users and then - typically - never change that key. Anyone who can recover your key can then decrypt all WEP traffic you've sent using it, compromise the privacy of your network and get a good handle on its access controls.

Based on several years of testing WEP products, we predicted the key recovery method employed by hacker tools such as WEPCrack and AirSnort (see How we did it) would be obsolete today because there are a variety of techniques that can defeat them. This round of testing proved that assumption dead wrong (see graphic, below). In addition to more than 40% of the products failing our WEP-cracking test, we found that some vendors actually have moved backward, meaning newer products might be more vulnerable to attack than older products.

Most vendors - trying to explain away the fact they are shipping code vulnerable to 3-year-old attacks - argued with us when we pointed to test results that showed their WEP implementations were cracked easily. Most justified their vulnerable WEP implementations by saying something akin to "if you were serious about security, you wouldn't be using WEP." That said, we still believe it's a bad idea to ship vulnerable products.

Although we checked with technical support regarding all products that failed our AirSnort test, only the three wireless switch vendors - Airespace, Aruba Wireless Networks and Trapeze Networks - went back to the lab and patched the holes for a retest.

AirSnort and WEPCrack aren't the only tools used to attack WEP. If you use 40-bit keys, there are tools such as KisMAC that can recover the key using brute force.