who are those anonymous hackers group? Are they doing good or they exploiting?

Anonymous is a decentralized international hacktivist group that is widely known for its various DDOS cyberattacks against several governments, government institutions & government agencies, corporations, and the Church of Scientology.

Anonymous originated in 2003 on the imageboard 4chan, representing the concept of many online and offline community users simultaneously existing as an anarchic, digitized global brain. Anonymous members (known as “Anons”) can be distinguished in public by the wearing of Guy Fawkes masks in the style portrayed in the graphic novel and film V for Vendetta.  However, this may not always be the case, as some of the collectives prefer to instead cover their face without using the well-known mask as a disguise.

It depends on how you see them.