Masks, Brute Force and Hybrid Attacks

Masks are used in Hashcat to perform brute force cracking. This is specified in Hashcat with the “-a3” switch. Some people frown on brute force cracking because of the wasted time in cracking. It has to try every combination of a pattern and can take an extended amount of time - hours, days, months, even years! (Side note, I don’t ever let it run for more than a day, just look through the ones it did crack for new patterns and try a better mask!) But it is absolutely necessary, especially when cracking hashes of unknown length and complexity. When you have exhausted all your wordlists, rules and combinator attacks, brute force is a great way to get a “fresh look” at the hashes and possibly see a pattern that you could use. Once you do find a pattern, you can step back and modify your mask to be more exclusive or switch to a specialized wordlist that contains those patterns.

Using Masks greatly reduces brute force...