The 12 most infamous hackers of all time

Guccifer, who also goes by Marcel Lehel Lazar, is best known for exposing the existence of Hillary Clinton's private email server.

He's hacked several American political figures, and was the first to distribute photos of former president George Bush's paintings. He also reportedly was able to hack into former Secretary of State Colin Powell's email and Facebook accounts.

The United States had him extradited from Romania in March of this year.

He stood trial and eventually pleaded guilty to identity theft and hacking charges on Thursday.

Ryan Collins of Pennslyvania pled guilty on Wednesday to orchestrating the celebrity iCloud hack known in the seedier parts of the internet as "the Fappening" or "Celebgate."

He'll probably serve 18 months for what he did, although he faces 5 years, which included leaking nude photos of Jennifer Lawrence and Kate Upton online.

Here's how the chef did it: he would phish celebrities with emails that looked like official password reset notifications from companies like Apple or Google. Then, armed with their passwords, he would use them to download full iPhone backups from iCloud — which came with contacts, text messages, calendars, and photos.

He might not even be the mastermind of the hack, though. Some suspect that he had assistance from others, including two Chicago men who had their homes searched as part of the investigation.

Adrian Lamo was known as the “homeless hacker” for his transient lifestyle. Despite that, he was able to hack into the internal computers of The New York Times in 2002.

This hack gave Lamo access to private databases, including one that had the private information of more than 3,000 people who had contributed to the paper’s Op-Ed section. He was sentenced to two years of probation and fined nearly $65,000. Most recently, Lamo was back in the headlines for turning in Chelsea Manning for leaking classified US Army documents.

Vladimir Levin was a Russian hacker who, in 1995, broke into Citibank's computers and allegedly stole nearly $10 million by re-wiring it to various global accounts. The most famous part of Levin's hack was that he did not use the internet to commit his crime.

Instead, he tapped into telecommunications systems to listen to customers rattle off their private account information. All but $400,000 of his winnings were able to be recovered by the authorities. Ultimately, he pleaded guilty to just one charge of making $3.7 million in unauthorized transfers, the Wall Street Journal reported.

He was sentenced to three years in prison and ordered to pay back $240,000 to Citibank.

Albert Gonzalez executed one of the largest-known identity thefts the world has ever seen.

In 2010 he was sentenced to 20 years in prison after confessing to stealing millions of personal credit and debit cards accounts. He was accused of stealing as many as 170 million credit card numbers, the Associated Press reported.

Gary McKinnon was a Scottish computer hacker who was able to gain access 97 American military networks between 2001 and 2002. He reportedly left the military a message on its website too: “Your security is crap.”

A computer prodigy by the age of 14, McKinnon was known for his preternatural way of infiltrating closely guarded computer networks. What’s of note about McKinnon (beyond his insanely-good hacking abilities) is that he was on a quest to prove the existence of UFOs.

In fact, McKinnon claims that he was able to access images of potential alien spacecrafts during his hacks, although his connection was too slow to actually download the photographs. The US has tried to extradite him, but he still lives in the UK’s asylum.

Kevin Poulsen was known as Dark Dante, a young 20-something hacker with a penchant for mischief. His alleged exploits include hacking into the LA phone networks to ensure he won a prize from a radio show and even hacking into the phone calls of a "Hollywood starlet," according to The New York Times.

After the feds started looking of him, Poulsen went on the run for 17 months. He was featured on the popular TV show "Unsolved Mysteries."

In what is considered one of the most famous hacks, when the show displayed a phone number for viewers to call-in they had any information, the phone lines for the program went instantly dead. After serving time for his online crimes, Poulsen turned to journalism. He now serves as a contributing editor at Wired.

The Syrian Electronic Army is perhaps the most well-known currently active global hacking group around today. It began in 2011 as a rogue online group in support of the Syrian President Bashar al-Assad.

Instead of stealing data, the SEA merely wreaks havoc. It's caused distributed denial of service (DDoS) attacks on numerous websites, and it has hacked into and spammed well-known websites like Twitter and Facebook. Their targets are generally Western-leaning Syria-opposing organizations. Famous SEA victims include the New York Times, the Onion, the Huffington Post, and LinkedIn.

Max Ray Butler, who went by the alias “Iceman,” was a computer security consultant who turned into one of the world's biggest hackers.

Arrested in 2007, Iceman digitally stole 2 million credit card numbers and ran up over $86 million in fraudulent charges. The federal authorities accused him of operating an online forum known as “Carders Market,” where hackers bought and sold stolen financial data. Butler is serving a 13-year sentence, which was the longest punishment ever inflicted on a hacker at the time.

Astra is the pseudonym of a Greek hacker who infiltrated the computers of the French aviation company Dassault Group and stole weapons technology data for over five years.

The information he accessed included confidential data about jet fighters and other military-grade aircrafts. Astra then sold this secret information to numerous countries over a span of five years. As a result of this infamous hack, Dassault’s losses hit more than $360 million. The actual identity of Astra has never been identified, but when he was apprehended in 2008 the authorities described him as a 58-year-old mathematician.

Anonymous is the name of the decentralized "hacktivist" group known for launching online hacking campaigns in support of current political and social events.

Anonymous's mascot is the Guy Fawkes mask. The group began in 2003 in the online forum 4chan. It first began as a way for online members to collectively pull pranks, but it morphed into an online "vigilante" service looking for justice. The group has targeted the Church of Scientology, the KKK, PayPal, and many other high-profile institutions. It is known for its tagline, "We are Anonymous. We are Legion. We do not forgive. We do not forget. Expect us."

Kevin Mitnick is perhaps one of the best known hackers to date. His exploits date a while back, but they are still remembered by the security industry.

During his young adulthood, Mitnick made free calls on his hacked cellphone and stole secret code from companies including Sun Microsystems and Novell, as The New York Times has reported. He even admits, according to The Times, to hacking into the NSA's phone calls.

In 1995, he pleaded guilty to multiple counts of fraud and served five years in prison. He now works as a professional security consultant.

Cale Weissman contributed to a previous version of this article.