The "biggest" hack depends on the metric, but the Yahoo Data Breaches (2013-2014) are often cited as the largest by number of affected users (3 billion). Other massive breaches include the 2020 U.S. Federal Government Hack (SolarWinds), affecting numerous agencies via a software supply chain attack, and the Bangladesh Bank Heist (2016), a massive financial theft of $81 million from a central bank.
1. Yahoo – 3,000,000,000 records lost. In 2013, hackers breached Yahoo's system and leaked customer info from over 3 billion accounts. Fortunately, the stolen data didn't include crucial information such as payment data, unhashed passwords, or bank account numbers.
What is hacking?
Technically, the very first cyberattack occurred in France in 1834. Two thieves stole financial market information by hacking the French Telegraph System. There were other “hackers” who emerged over the years to disrupt phone service and wireless telegraphy, but it wasn't until 1940 that things got really interesting.
Why are grey hat hackers illegal? Any time you break into a network or computer system that you don't have permission to enter, you're not acting ethically or legally. Even with good intentions, you'll be at risk for legal action if you engage in grey hat hacking.
Black Hat Definition. Black Hat Hackers refers to hackers with malicious intentions who gain unauthorized access to computer networks and systems. Black hat hackers aim to exploit security vulnerabilities in software or corporate systems.
A black-hat hacker is a person that illegally breaks into computer networks. They may be aiming to steal log-in credentials, personal and bank information, modify or delete stolen data, sell data on the dark web, or commit other malicious cybercrimes.
Computer Fraud and Abuse Act
If you are charged with federal hacking crimes under 18 U.S.C. § 1030, you could face up to a year in federal prison for lesser offenses, between 10-20 years for more serious offenses, and even life in prison if the hacking resulted in someone's death.
The Most Notorious Cyberattacks In History
1969 — RABBITS Virus — An anonymous person installs a program on a computer at the University of Washington Computer Center. The inconspicuous program makes copies of itself (breeding like a rabbit) until the computer overloads and stops working. It is thought to be the first computer virus.
The most notorious hackers of 2025 include: Lazarus Group (TraderTraitor), IntelBroker, Scattered Spider, Predatory Sparrow, Dark Storm Team, and Anonymous Sudan ,responsible for the most disruptive and financially devastating cyberattacks this year.
A zero- ay exploit is the method an attacker uses to access the vulnerable system. These are severe security threats with high success rates as businesses do not have defenses in place to detect or prevent them. A zero day attack is so-called because it occurs before the target is aware that the vulnerability exists.
Yahoo Data Breaches (2013–2014)
A data breach affecting online giant Yahoo in 2013 resulted in what's still the biggest corporate leak of all time. The attack, revealed in 2016, reportedly saw three billion accounts compromised – with email addresses, names, and phone numbers among the data stolen.
More than 90% of successful cyber-attacks start with a phishing email.
There isn't one single "hacker number 1," but Kevin Mitnick is widely considered the world's most famous hacker, known for his teenage exploits, hacking into NORAD, inspiring War Games, and later becoming a renowned security consultant, bridging the gap between black-hat notoriety and white-hat expertise. Other legendary figures include groups like Anonymous, known for cyber activism, and modern threat actors like the extortionist group Lapsus$.
The early days of hacking, exemplified by Kevin Mitnick's exploits, laid the foundation for the evolving world of cybersecurity. Mitnick's actions not only revealed vulnerabilities in systems but also underscored the need for robust security measures to protect against unauthorized access and data breaches.
The RockYou2024 breach, the largest password dump in history, has exposed nearly 10 billion credentials, highlighting the urgent need for robust cybersecurity measures.
The most common countries where hacking and cyber warfare attacks come from are:
Tools like stalkerware apps, often used by abusive partners, or financially motivated Android malware such as SpyLoan, have been detected exploiting cameras to monitor victims or collect compromising video material.”
Cyber. The FBI is the lead federal agency for investigating cyberattacks by criminals, overseas adversaries, and terrorists. The threat is incredibly serious—and growing.
Lack of evidence. Unlike physical crimes, digital crimes leave behind data rather than fingerprints and tangible evidence. Any hacker worth his or her salt will frequently delete logs, encrypt communications and use malware that self-destructs to prevent the accumulation of any evidence that can be used against them.
Grey hat hackers are a unique subset of computer experts who exist between white hat and black hat hacking. The term grey hat refers to an individual who operates without malicious intent but still violates laws or acceptable standards of behavior by exploiting security vulnerabilities without permission.
The term ethical hacker includes all security professionals who provide offensive services, whether red team, pentester, or freelance offensive consultant. Security analysts or engineers are also job titles that may include offensive elements.
A blue team is an internal IT security team that is there to defend against cyberattackers, including red teams, which can threaten your organization and strengthen its security posture.