Conscientious computer users do not share their passwords. Neither should their computers. Since almost the dawn of computer networking, however, users have been able to log onto any computer on a network with just one password. Computers on the network must therefore have a way of securely sharing passwords. If storage of these passwords is secure enough, crackers will not be able to use certain techniques to speed their work, such as consistant lookup tables. The two methods Microsoft™ has implemented to store passwords on Windows™ networks contains weaknesses which allow
cracking of passwords in just a few seconds.
Microsoft Windows passwords are stored without any random information. This means a password stored on one computer will be identically stored on another. With the password hash tables from one computer on a network, a lookup table can be used to dramatically speed password cracking. Unix, Linux, and Mac OS X use a 12-bit salt when generating hash entries, making each password's storage different on each computer. Crackers can therefore not use the same time saving methods to gain access to other computers after gaining access to one.
The fact Microsoft Windows uses weak techniques in storing passwords is nothing new. But with all of the information provided by security researchers one would expect Microsoft to do more about it.
References:
- Making a Faster Cryptanalytic Time-Memory Trade-Off by Philippe Oechslin
- Advanced Instant NT Password Cracker
- Cracking Windows passwords in seconds on CNet News.com