Cracking WEP
- Home Wireless Local Area Network Users
- The Secret Key
- XOR
- RC4
- Array Swapping
- KSA
- PRGA
- CRC
- Putting It All Together
- Cracking WEP
- Walking Through the KSA
- Simplifying the Process
- Patching the Hole
- Summary
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Like this article? We recommend
Like this article? We recommend
Since mid-summer 2001, wireless network security has been a hot topic. The fact that most wireless networks are not secured has been reported, discussed, lectured on, and more. About the only way you could have avoided this is if you were completely removed from every form of paper and electronic media.
However, all this media hype has not had the desired effect! Believe it or not, an estimated 60%–70% of all wireless networks in existence are still NOT using even the most basic of protections. As a result, any hacker can drive around the block and probably find an open and hackable wireless network. This is problem number one.
Problem number two is a bit more technical, and will be the main subject for this article. This problem concerns the weaknesses surrounding WEP. The Wired Equivalent Privacy protocol defines how a wireless network is secured. In short, it determines what encryption and authentication method is used to secure wireless data. The problem with WEP is in the way the data is encrypted. As discovered by three researchers, WEP can be cracked by anyone with a sniffer, which is the name given to the hardware device or software that can capture data as it flies through the air. This basically means that all those companies that think they are securely using their wireless network are doing so under false pretenses. This article deals with this issue, and explains just what cracking WEP means. I will show you just how hackers will attack you and take advantage of this weakness to capture your secret key right out of the air, which they can then use to connect to your secure wireless network.
Home Wireless Local Area Network Users
Before delving into the details of WEP, it must be understood that there are two main categories of WEP users. Many home users don't bother setting up WEP because they considered it a waste of time since WEP is crackable, or because they find it too complicated. If you are the latter, find someone who knows how to enable WEP, and offer them dinner. Regardless of the issues surrounding WEP, it should be understood that cracking WEP is not as easy as everyone makes it sound. Although cracking WEP is possible on the typical home-owned WLAN, it would take two to four weeks to capture enough data to successfully extract the key. In other words, by simply enabling WEP and changing the secret key periodically, you can be fairly certain that your WLAN will not be hijacked by a hacker. That said, let's take a look at how cracking WEP appears from a hackers point of view.