There was a time when hacking was just considered “cool,” but as more and more segments of the government upgraded to computers, hacking has now become a national security threat to countries around the world.

So much so that countries have had to pass legislation to ensure that hackers don’t get out so easy. But of course, finding a hacker isn’t as easy as locating a local criminal. Using multiple ISPs, these hackers can create havoc a million miles away, just by sitting in their bedroom.

Over the last few years, hackers even got glorified thanks to shows like House of Cards and Mr Robot. And why wouldn’t they? It is kind of amazing to think that a bunch of people can hack into someone as powerful as Hillary Clinton’s emails or hack into all the details of the UK government.

The most recent virus, Wanna Cry, attacked thousands of computers in China and Japan. The Russian and American government blamed each other for the virus wave. However, there has been no second wave of attacks.

While most of the current hackers remain anonymous because they want to protect themselves and essentially don’t want to go to jail forever, there are some hackers whose identities have been uncovered over the years.

Here are most infamous hackers of all time:

15. Jonathan James

Famously known as Comrade by many online, Jonathan James was the first teenager to be convicted and jailed by the government of United States of America for hacking. He hacked big companies like Bell South, Miami-Dade School, and even the Department of Defence in 1999. Through the latter, he gained information about International Space Station.

Once NASA got to know about it, all the computers were shut down for three weeks, and there was a total loss of around $41,000. In 2007, the Boston Market, Barnes & Nobles, and OfficeMax were the victims of another massive attack by him. In May 2008, James was found dead after a self-inflicted gunshot.

14. John McAfee

As a resident of Belize, John McAfee wanted to study plants. Not plain plants but psycho-active plants, and set up a lab for their study. However, his properties were seized. An official from the government came looking for McAfee, asking him for bribes, which he denied.

To get back to the Belize government, McAfee hacked all the computers of their system. John found shocking revelations about the Belize government bureaucracies which unfolded information about government officials involved in corruption, murder, money laundering, and drug abuse. To escape the government, John faked his own death and almost got away with it.

13. Adrian Lamo

Adrian Lamo got popular after breaking into the computers of The New York Times, Yahoo!, MCI, WorldCom, and Microsoft. After he was found guilty, Adrian was sentenced to six months of house arrest and two years of probation. He was also ordered to pay $65,000 as reimbursement. Known as Homeless Hacker, Lamo was out of the limelight for some time.

But he came back into the limelight when he refused to give his blood sample for the CODIS system of the the American government. It is a DNA database used to identify criminal suspects. Adrian was in the news recently for turning in Chelsea Manning who disclosed confidential US Army documents.

12. John Draper

John Draper, famously known as Captain Crunch, discovered that the whistle found in Cap’n Crunch cereal produced a 26,000 Hertz frequency sound. It is the same frequency used by AT&T for indicating that a trunk line is ready for a new call. He used this new found knowledge to produce other sounds by the phone company.

John was arrested in 1971 after Esquire published a story about Phone Phreaking. He was sentenced to five years of probation.

The publicity helped Stephen Wozniak to come into contact with the hacker. Steve Jobs and Wozniak eventually hired him to build the telephone interface for the Apple II.

11. Astra

A Greek hacker going by the pseudonym Astra gained excessive fame after he hacked into the French Aviation company Dassault Group’s computers. He stole weapon information for five years before he was found guilty. During this time, Astra sold information about jet fighters and military aircraft to different countries for around $1,000 each. This cost the Dassault Group a loss of $360 million.

His real identity has never been revealed, but rumors say that he is a 58-year-old mathematician. Astra was arrested in January 2008 and sentenced to six years in jail.

10. Stephen Wozniak

We all know Wozniak founded Apple along with Steve Jobs. While Stephen was studying at the University of California, he made devices called blue boxes, which enabled free long-distance phone calls. Wozniak was so excited about the new technology that he even used these blue boxes to call the Pope. And this was the first official phone phreaking case.

Taking the help of John Draper, who already had a lot of knowledge about phone systems and phreaking, Wozniak was also able to build the telephone interface for the Apple II computer.

9. Vladimir Levin

Vladimir Levin is a biochemistry graduate and a Russian hacker. In fact, he is a rather respected figure among hackers known for hacking the Citibank computers in 1995 and re-routing its money to other bank accounts around the world. Levin didn’t use the internet to hack the system, but rather tapped into the telecommunications systems and listened to the customers’ state their account information. He logged in 18 times in a month to transfer a sum of $3.7 million.

$400,000 was retrieved, and Vladimir pled guilty for transferring $3.7 million. He had to spend three years in prison and pay back $240,000 to CitiBank, by the government.

8. Gary McKinnon

Gary McKinnon gained popularity between 2001 and 2002 when he hacked 97 American military networks. He made all the computers display a message saying, “your security is crap.” McKinnon’s aim was to decipher information about the existence of UFOs, however, the US government was successful in stopping his efforts. This hack of his is considered as the biggest military computer hack of all time.

He claims that he was able to get access to images of potential alien spacecrafts when he hacked the military networks. Due to weak connection, he couldn’t download the images. Gary has left his hacking practices in the past and has become a full-time SEO wizard.

7. James Kosta

James Kosta and his partners are known for hacking systems of huge companies like General Electric and IBM when he was just 14 years old. He was convicted of 45 technical burglaries and was sentenced to 45 years in prison. But instead, he joined the US Navy as an intelligence analyst at the age of 18. At 20 years of age, he joined the CIA to track warlords in the Middle East and Africa, and by the time he was 24 James had sold his first dot-com company for millions of dollars.

He now works as a motivational speaker, guiding and mentoring troubled youth to help them reach their full potential.

6. Kevin Mitnick

At the young age of 12, Kevin hacked the Los Angeles bus software to gain access to free rides by bypassing their punch card system. By the time Mitnick turned 17, he mastered the art of hacking the phone system to redirect calls. Kevin went on to hack many systems until he was captured by the FBI. Computer scientist and security expert, Tsutomu Shimomura helped the FBI in catching Kevin Mitnick.

He was sentenced to five years of jail term. Kevin is no more a part of the hacking world and runs his own security firm, Mitnick Security Consulting, LLC.

5. Michael Calce

Michael Calce got famous for taking down companies like eBay, Yahoo!, CNN, Amazon, and Dell through Distributed Denial of Service Attacks (DDoS). This caught the attention of the FBI and the Royal Canadian Mounted Police who caught him through an IRC chatroom.

Michael was just 18 years old at that time and was sentenced to eight months of open custody and one year of probation. Later, he wrote a book which documented his digital attacks. He describes internet security as too lax.

4. David L. Smith

David L. Smith, also known as Kwyjibo, is the creator of the Melissa worm virus, the first successful email-adware virus which was distributed in the Usenet discussion group in the form of – alt+sex. His email-adware virus caused more than $80 million of damage.

It is surprising that he hadn’t release the virus for money, but just for the kick. After he was found guilty, he cooperated with the forces and agreed to work with the FBI to reduce his term. Smith then served 20 months in jail. He is considered as one of the most notorious hackers in history.

3. Albert Gonzalez

Albert Gonzalez is considered as one of the biggest thieves to ever be caught in the history of cybercrimes. He was sentenced to 20 years in jail after he confessed to stealing millions of debit and credit card numbers.

He earned so much money during his hacking days that he threw himself a birthday party worth $75,000 and complained of sore hands after counting $340,000 in cash (because his money counting machine broke).

Albert is responsible for stealing around 170 million credit card numbers. He was arrested in 2008 and held responsible for busting into the Dave and Buster’s corporate network.

2. Kevin Poulsen

Famously known as Dark Dante, Kevin Poulsen was a young 20-year-old boy known for hacking into the LA phone networks so that he could win a prize from a radio show in his area. He even hacked the phone calls of a famous Hollywood actress.

Once his hacking antics were realized by the feds, he went undercover for 17 months. Kevin has also been featured on a popular television show, Unsolved Mysteries.

After serving his time in the prison, Kevin returned into the limelight as a journalist and now works as a contributing editor at Wired.

1. Max Ray Iceman Butler

Max Ray Butler, popularly known as Iceman, worked as a computer security consultant before becoming one of the biggest hackers in history. Before his arrest in 2007, Max Ray Butler was successful in digitally stealing 2 million credit card numbers and caused a total loss of $86 million.

He was accused of operating an online forum known as Carders Market which was a platform where hackers could buy and sell stolen financial data. Currently, Iceman is serving a 13-year prison sentence, which is the longest prison term given to any hacker, ever.