Internet Security--A Plan of Attack

Worse, computer systems without proper security can be vulnerable to even more serious, and potentially devastating, attacks: attacks in which data are altered or corrupted; attacks in which customer files are damaged or compromised; attacks which can bring down an entire company's network.

"The worst type of attack is one that involves data compromise," Slotnick notes, adding that a hacker can gain 'read-only' access—meaning that he or she can read the information but cannot change it—or modification access.