Greatest Hacks of All Time

Ashley Madison Hack 2015: 37 Million Users

The hacker group Impact Team broke into the Avid Life Media servers and copied the personal data of 37 million Ashley Madison users. The hackers then incrementally released this information to the world through various websites. The effect on people's personal reputations rippled across the world, including claims that user suicides followed after the hack.

This hack is memorable not only because of the sheer publicity of the aftermath, but because the hackers also earned some fame as vigilantes crusading against infidelity and lies. 

The Conficker Worm 2008: Still Infecting a Million Computers a Year

While this resilient malware program has not wreaked irrecoverable damage, this program refuses to die; it actively hides and then copies itself to other machines. Even more frightening: This worm continues to open backdoors for future hacker takeovers of the infected machines.

The Conficker worm program (also known as the Downadup worm) replicates itself across computers, where it lies in secret to either convert your machine into a zombie bot for spamming or to read your credit-card numbers and your passwords through keylogging then and transmit those details to the programmers.  

Conficker/Downadup is a smart computer program. It defensively deactivates your antivirus software to protect itself.

Conficker is noteworthy because of its resilience and reach; it still travels around the Internet eight years after its discovery.

Stuxnet Worm 2010: Iran's Nuclear Program Blocked

A worm program that was less than 1 MB in size was released into Iran's nuclear refinement plants. Once there, it secretly took over the Siemens SCADA control systems. This sneaky worm commanded more than 5,000 of Iran's 8,800 uranium centrifuges to spin out of control, then suddenly stop and then resume, while simultaneously reporting that all is well. This chaotic manipulating went on for 17 months, ruining thousands of uranium samples in secret and causing the staff and scientists to doubt their own work. All the while, no one knew that they were being deceived and simultaneously vandalized.

This devious and silent attack wreaked far more damage than simply destroying the refining centrifuges themselves; the worm led thousands of specialists down the wrong path for a year and a half and wasted thousands of hours of work and millions of dollars in uranium resources.

The worm was named Stuxnet, after a keyword found in the code's internal comments.

This hack is memorable because of both optics and deceit. It attacked the nuclear program of a country that has been in conflict with the USA and Israel and other world powers and it also deceived the entire Iranian nuclear staff for a year and a half as it performed its deeds in secret.

 

Home Depot Hack 2014: Over 50 Million Credit Cards

By exploiting a password from one of its stores' vendors, the hackers of Home Depot achieved the largest retail credit card breach in human history. Through careful tinkering of the Microsoft operating system, these hackers managed to penetrate the servers before Microsoft could patch the vulnerability.

After they entered the first Home Depot store near Miami, the hackers worked their way throughout the continent. They secretly observed the payment transactions on more than 7,000 of the Home Depot self-serve checkout registers. They skimmed credit card numbers as customers paid for their Home Depot purchases.

This hack is noteworthy because it was launched against a large corporation and millions of its trusting customers.

eBay Hack 2014: 145 Million Users Breached

Some people say this is the worst breach of public trust in online retail. Others say that it was not nearly as harsh as mass theft because only personal data was breached, not financial information.

Whichever way you choose to measure this unpleasant incident, millions of online shoppers have had their password-protected data compromised. This hack is particularly memorable because it was public and because eBay was painted as weak on security because of the company's slow and lackluster public response.