A cracker is a person who enters a computer system without authorization. The goal of the cracker is to crack the security systems, create chaos and use the obtained confidential data for their own commercial interests. This may involve computing power that is misappropriated for free, or the use of resources. By attacking web servers, modifying data or launching DoS attacks, crackers cause damage to systems.
In contrast, hackers merely overcome security systems, expose their vulnerabilities and leave their specific calling card. In German usage, a cracker is also a person who cracks the copy protection of systems.
The difference between a cracker and a password cracker is that the latter is a password cracking program. It can be used when the password has been forgotten or misplaced, but also specifically to gain unauthorized access to a computer or network resources. In password cracking, the password is determined using a wide variety of techniques. One of them is the brute force attack, where all possible alphanumeric combinations of an appropriate word length are entered until the correct combination is found. Another is the dictionary attack, which works with word lists. There is also the rainbow table method, phishing and spidering.