http://www.howsecureismypassword.net/

The latest version of OS X Lion allows any user to easily change the password of any local account, due to permissions oversights on Apple’s part. The news comes less than a month after another Lion vulnerability that let users bypass LDAP without a password gained notoriety.

Originally reported by Defence in Depth blogger Patrick Dunstan, the root of the newly discovered problem in Mac OS X 10.7 is tied to the user-specific shadow files used in modern OS X platforms. These files are essentially hash databases and contain, among other things, the user’s encrypted passwords. Ideally, they should be accessible only via high-privilege accounts.

According to Dunstan, Apple dropped the ball in terms of how Lion handles privilege. “Whilst non-root users are unable to access the shadow files directly, Lion actually provides non-root users the ability to still view password hash data,” Dunstan wrote. “This is accomplished by extracting the data straight from Directory Services.” Any user can accomplish this trick by simply invoking the directory services listing using the /Search/ path — for example, $ dscl localhost -read /Search/Users/bob (where “bob” is the username). This causes Lion OS X to spew out the contents of Bob’s shadow hash file, including data that can be used to crack Bob’s password with a simple script, such as a Python script written by Dunstan.

Source: Info World

Here’s an example project we made for a Windows7 box that adds a new Admin user to the system and hides that user from the logon screen. the whole process takes about 16 seconds , with most of the time taken by the device being detected as a keyboard and the driver installed. The device costs about $20 and can be found here

of course unless they’re using a nice setup and using gpu power

For example, if we had a passwd file entery such as:
chrisa:x:107:102:Chris Anderson:/home/chrisa:/usr/bin/bash

We could have MAPDAV derrive some possible passwords, such as chrisa, chrisanderson, andersonchris, canderson, ChrisAnderson, Anderson Chris, CHRIS, plus any other combinations you entered. It has quite a few other features you can use to modify the output to have arbitrary characters, be in reverse, and other useful things.

Out of a sample of 30192 users, MAPDAV 1.0p8 cracked 4.7% of the passwords on the default settings, 1.2% of which were NOT the same user/pass. This combind with a good conventional wordlist could give good crack results.

More info: http://mapdav.sourceforge.net

1. Instead of generating 4096 tables of 1-8 character passwords, just create 1 table of 3-10 character passwords, and use the 1st two characters of the plaintext passwords as the salt. (That part will make more sense if you read the paper.)
2. It’s still kind of slow: 9x slower than LM hashes, for example. But CPUs are much faster than they were in 2003, when people first started building tables for LM hashes.
3. It also takes a lot of storage. But storage, likewise, is much cheaper than it was seven years ago.

The whitepaper can be found here: http://bit.ly/ij8hQU