LC3’s Power Features

You might feel depressed when you see the amount of time it takes to complete a large-character-set brute-force password-cracking session. If you need fast results, LC3 has some powerful features that can speed up the audit process. First, LC3 automatically takes advantage of multiple-CPU computers by spawning a separate thread for each CPU. Thus, a dual-CPU computer should crack almost twice as fast as a single-CPU machine. However, you can also spread the work of an audit across several different computers at your disposal. To do so, import your password hashes as usual but select File, Save Distributed Sessions in the LC3 UI. In the Save Distributed Sessions dialog box, which Web Figure A shows, select a destination folder, and enter the number of computers you have available for the audit. Then enter a filename prefix. When you click Save, LC3 will create X number of files named with the prefix and a number. Figure A shows that LC3 will create four such files named dist1, dist2, dist3, and dist4. Then, start LC3 on each computer, load the appropriate .lcs file, and start the password-cracking process. Four computers should cut your usual crack time to 25 percent.

If you have several domain or computer SAMs you must crack, you can combine them in one file. The advantage is that, provided you used any other method than the sniffer to import the passwords, LC3 can crack 1000 passwords almost as quickly as it can crack 100. To combine several systems into one audit, simply start LC3 on your first system as usual and import your passwords. Then, save the file and take it to the next computer. This time, start LC3, then open the LC3 file you created on the first computer. Import the password hashes, save the file, and move on to the next computer.