Guessed or stolen credentials
Guessed or stolen credentials

Keyloggers installed on infected machines are a common way for attackers to discover a user's password or credit card information. But many times attackers don't need to install malware to steal credentials.

"Absent, weak, and stolen credentials are careening out of control," Verizon said in its report. Two-thirds of breaches involved stolen or guessable usernames or passwords.

One easy way for attackers to steal credentials includes clicking the "forgot password" button and guessing security questions. Those can be easy to guess if the attacker knows anything about the victim.

For instance, a hacker was able to log into Sarah Palin's personal Yahoo Mail account just by going on Wikipedia. Her security questions included her birthday and the name of her high school.

Last updated July 29 2011: 5:11 AM ET
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