With the volume of data breaches on the upswing, it can be tough keeping track of all the threats. To sort the LulzSecs from the Zeuses, NetworkWorld's Ellen Messmer presents an overview of some of the busiest hacker groups and their methods and goals.

Hackers with a cause, a.k.a. hacktivists, tend to disrupt their targets with denial of service attacks or steal data for the purpose of exposure. This category includes Anonymous, which is tied to DoS attacks on Amazon, Visa, PayPal and others. The group's focus these days appears to be largely political, with recent attacks on government websites in Egypt, Libya and Tunisia during uprisings in these countries. As hackers go, this brand tends to be quite public about its activity.

Other hackers have a much more material gain in mind. Those behind the Zeus attacks aim to steal financial data from targets' PCs to conduct transfers in corporate bank accounts. These hackers have perpetrated millions of dollars worth of fraud, according to the FBI. While law enforcement nabbed approximately 100 Zeus suspects last fall, there remain five distinct Zeus groups wreaking online havoc worldwide, according to a security expert with Dell SecureWorks.

China is reportedly home to a plethora of hacker groups. Some of the more infamous groups include the Green Army Corps, Janker and the Network Crack Program Hacker Group. Today, some hackers in China are putting in regular shifts to break through oil companies' defenses and steal information, security provider McAfee alleged in a report (.pdf) dubbed "Night Dragon."

Messmer's article provides details on a number of other groups, including Dogma Millions in Russia and the latest headline-grabbing operation, Inj3ct0r Team.

For more:
- read the "Night Dragon" report (.pdf) from McAfee
- see Ellen Messmer's article at Network World

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