They are also one of the greatest sources of vulnerability. If left to their own discretion, a surprisingly high number of users will select passwords that are fairly easy for hackers to crack using password checking dictionary programs, or even simple guessing. Upgrading the security of your password system presents a classic example of the security versus usability dilemma discussed above. Long computer-generated random passwords are harder for hackers to crack, but they are also harder for legitimate users to remember. They could be less secure overall if users wind up taping them to their monitors.
Firewalls are another method of controlling access.
They use software to screen out unwanted intruders from the Internet. Firewalls can help, but it would be unwise to rely on them as your sole security measure, as too many law firms seem prone to do. This attitude can lead to disaster. A high percentage of firewalls are improperly configured. Further, in many cases even firewalls that are properly configured can be defeated by a skilled, determined attacker.