Tuesday, December 13, 2011

Cracking WEP....part 1 of a little bit of frustration

I found a new project that I want to work on. Actually, I was invited to work on yet another web-based application project that I think will be completely awesome. But that is not the project I am referencing for this post. Nope...I want to play around with password cracking.

I know that WEP is not the strongest; it is the easiest to crack anymore, especially with methods such as the PTW approach (Pychkine, Tews, Weinmann) or the older Korek attack (either one can be easily run through aircrack-ng). However, after an interesting time at a relatives (one of my Michigan cousins named Henry....one of three) over thanksgiving week, I wonder more and more about the issues surrounding the creation, storage, and transmission, of solid passwords.

A password should be hard to crack, easy to memorize, should work on the system it's established for (think earlier LANMAN stuff). I think everyone agrees upon this. However, there have been some divergent schools of thought for sometime now on what a "solid" or "strong" password consists of in general terms. Everyone with access to something on the Internet in the last decade has had to have noticed the change in complexity requiremenets. It is not uncommon anymore for a password to have requrements such as:

- length (12+ chars)
- at least one from each group:
---- uppercase letters
---- lowercase letters
---- numerals
---- special charactors (%,#,$,%,^,&, for example)
- can't be reused X amount of times
- and so on.
On top of making a password hard to guess...and hopefully hard to crack (although I believe that ALL passwords, given the time and processing power, can be cracked), the method of how a password is encrypted and transmitted is constantly being revised and tested. Some of these include client-side encryption (OR hashing, with or without a salt), server-side (BAD Idea if you ask me), WEP, WPA2 with PEAK, etc.

Getting back to my point, I recently stayed at Henry's (my relative) house. I was on vacation and had zero desire to do anything with a computer. That was until he made a comment about his wireless router password using WEP. He didn't challenge me, but I thought it would be fun to capture some traffic and see if aircrack-ng, or even Cain & Able could crack his password. So, I deferred getting the password from him and proceeded to break out my AirPCAP tool and just "collect" some IV's. I figured that with 128-bit encryption set on his six year old router, that it wouldn't take long to gather enough IV's and crack the password. Afterall, my wife's cocky aunt had refused to give me her WPA2 protected password and I proceeded to gain that one (and two of her neighbors accidentally) within about 20 minutes. (I should add, with some cockyness, that she hasn't tried to talk trash to me again...LOL). Since the WPA2 crack was SOOOOO quick, and since my unique IV collection amount kept climbing rather quickly, I was certain that I would have his password in no time.

I was wrong. Henry's password proved to be VERY difficult for aircrack, using either Korek or PTW attacks. I decided to query Henry about his setup....I wasn't trying to force anything, just trying to crack gracefully. After talking with Henry, I verified that: 1) he was not broadcasting his ESSID (Cain picked that up for me really quickly though), it was only WEP he was using, and that NO special charactors were used. One question I neglected to ask him was the length of his password. It was LONG...30 chars
I decided that I would collect at least 50,000 unique IVs. With a 128-bit key, PTW should be OK with 40,000+ IVs. I let this collection run for awhile (I didn't actually clock it) and then piped it to the cracker.

The aircrack-ng GUI provides a relatively great UI. I used a variety of settings to attempt both the Korek attack and the PTW attack, even though I was seriously short of IVs for Koreks. I tried with and without using a known ESSID and/or BSSID, and after seeing the password, I tried adding 1,2,3,4, and 5 of the first decrypted charactors. No Joy!!! I couldn't believe it. I chalk some of this failure up to my trying to be gentle. However, and here is where my new side-project is coming from, it REALLY got me thinking about the value of computational complexity versus a just plain long password of numbers and letters. An interesting side not to this was that Henry's password contained ONLY charactors used in hex (A-F and 0-9), had at least two dictionary words at the start of the password and used some pretty common key-stroke patterns.

So know I want to spend some quality time with different crackers, password creation methods, encryption and hashing algorithms, etc. and just run some test on cracking WEP versus WPA2 and using passwords that contain only alpha-numerics and NOT special charactors. I think I will also compare passwords that are collections of dictionary words versus complex passwords. This just sounds like a LOT of fun to me.

I know that these types of evaluations have been done numerous times...but it sounds like fun AND it sounds like a realistic way to get more familiar with the tools and get reaquainted with some of the protocols. In any event, I am rambling which means I need to call it a day. Tomorrow's a busy day of more compliance work and a Doctor's appointment...yay. Plus, I guess it's time to start getting some rest if I am going to initiate this project and a few others I mentioned in an earlier post.