Hacking Examples (2023): The 10 Worst Attacks of All Time

By Tibor Moes / Updated: May 2023

Hacking Examples (2023): The 10 Worst Attacks of All Time

Hacking Examples

Imagine you’re home, safe and secure. Suddenly, a stranger sneaks in, snooping around, and takes your most precious belongings. Now, translate that scenario to the digital world – that’s hacking.

Hacking is like a digital burglary, and in this article, we’ll delve into the most notorious hacking examples of all time. Just like recalling the most audacious robberies in history, our journey will reveal the magnitude and audacity of these virtual heists.


Hacking describes a range of activities that aim to compromise computers and networks by exploiting their security vulnerabilities. Although hacking can be used for good, most attacks are carried out for the benefit of the hackers.

  1. Morris Worm (1988): One of the first recognized instances of a computer worm distributed via the Internet.
  2. Kevin Mitnick Attacks (1994-1995): Once the most-wanted cybercriminal in the U.S, Mitnick broke into dozens of systems, stealing proprietary software.
  3. Yahoo Data Breach (2013-2014): Uncovered in 2016, it is considered the largest data breach in history, affecting all 3 billion Yahoo users’ accounts.
  4. Target Stores Data Breach (2013): Hackers stole credit and debit card information of about 40 million customers.
  5. Sony Pictures Hack (2014): Hackers leaked unreleased films, sensitive documents, and employee data, leading to massive financial and reputational losses.
  6. The Home Depot Breach (2014): Cybercriminals accessed around 56 million credit and debit card details.
  7. Ashley Madison Hack (2015): Hackers exposed personal details of users on this adult dating site, leading to personal scandals and even suicides.
  8. WannaCry Ransomware Attack (2017): This malware encrypted users’ data and demanded Bitcoin as ransom, affecting hundreds of thousands of computers globally.
  9. Equifax Data Breach (2017): Personal information of nearly 147 million people was exposed in this major breach.
  10. SolarWinds Hack (2020): A sophisticated cyber espionage operation allegedly backed by a nation-state that affected multiple US government agencies and companies.

Don’t become a victim of hacking. Protect your devices with the best antivirus software and your privacy with the best VPN service.

Hacking Examples In-Depth

1. Morris Worm (1988) – A Curious Experiment That Went Wrong

In the late autumn of 1988, the digital landscape faced its first significant tremor: the Morris Worm. This attack wasn’t the work of an organized crime group or state-sponsored entity, but rather an individual. A young, brilliant mind named Robert Tappan Morris, a graduate student at Cornell University, wanted to measure the size of the internet. However, his curious experiment quickly spiraled out of control.

The worm was supposed to visit machines, leave a small footprint, and move on. Instead, due to an error in the code, it multiplied aggressively, consuming system resources and slowing down computers, sometimes to the point of being unusable. This digital plague spread across the United States and beyond, touching international borders and signaling that the internet, in its nascency, was already susceptible to significant threats.

Thousands of machines, primarily at universities and research facilities, fell victim to this worm, causing an estimated financial damage of $10-100 million. This figure might seem small compared to more recent attacks, but it was a staggering amount at the time, especially considering the internet’s limited use.

The worm didn’t steal personal or financial data, but it did disrupt services and cause a significant disturbance in the academic and research communities. The authorities eventually managed to halt the worm’s spread, and the incident led to the development of the Computer Emergency Response Team (CERT), which serves as an important line of defense against cyber threats to this day.

Morris, who never intended to cause damage, became the first person to be convicted under the Computer Fraud and Abuse Act. He was sentenced to three years of probation, 400 hours of community service, and fined $10,050.

2. The Misadventures of Kevin Mitnick (1994-1995) – From Prankster to Most-Wanted

Fast forward to the mid-90s, and we find ourselves in the era of Kevin Mitnick. Unlike Morris, Mitnick’s hacking escapades were far from accidental. A gifted hacker, Mitnick orchestrated a series of attacks from 1994 to 1995, targeting dozens of systems and stealing proprietary software from several companies.

Mitnick’s escapades began as pranks and misdemeanors when he was a teenager, but his activities escalated into serious crimes. His targets were primarily businesses, which he infiltrated to steal valuable software and sensitive data. His hacking adventures were not confined to one geographical region but spanned across the United States.

While it’s challenging to quantify the exact financial damage caused by Mitnick’s activities, estimates run into the millions. He affected a significant number of businesses, though the exact number remains unknown. The data he compromised was primarily proprietary software and corporate information, causing substantial harm to the targeted companies.

Mitnick’s reign of digital terror came to an end when he was arrested by the FBI in 1995. His capture marked the end of a two-and-a-half-year manhunt, making him one of the most wanted cybercriminals in the United States. Mitnick served five years in prison, including eight months in solitary confinement. After his release, Mitnick turned a new leaf and became a consultant, using his knowledge to help protect against the kind of attacks he once perpetrated.

3. The Yahoo Data Breach (2013-2014) – A Digital Tsunami

A quiet digital storm was brewing in 2013 and 2014, one that even the victims were unaware of until 2016. This was when Yahoo, the once dominant web services provider, announced the largest data breach in history. Unlike the previous incidents, this attack wasn’t the work of a lone wolf but was orchestrated by a group of hackers allegedly backed by a nation-state.

Every single one of Yahoo’s 3 billion users worldwide became victims, their personal data stolen and floating in the ether of the dark web. The compromised information wasn’t just email addresses and passwords, but also security questions and answers – a veritable treasure trove for any cybercriminal.

This massive hack stretched across the globe, sparing no country where Yahoo had users. The financial fallout was equally colossal, and while the exact figure remains elusive, it undoubtedly ran into hundreds of millions. Yahoo’s reputation took a severe hit, and the company had to slash the sale price of its core business to Verizon by $350 million in the aftermath.

Authorities, along with Yahoo’s internal security, managed to identify and plug the security flaws that allowed the breach. However, the aftermath of the hack continued to echo for years. In 2017, the U.S. Department of Justice charged four individuals, including two officers from the Russian Federal Security Service (FSB), in connection with the hack.

4. Target Stores Data Breach (2013) – The Retail Nightmare Before Christmas

As the holiday season approached in 2013, an unseen Grinch was planning a massive heist. However, this was no whimsical tale. The target was Target, the second-largest discount retailer in the United States.

This hack was the work of an organized crime group. They infiltrated Target’s systems and planted malware on the point-of-sale (POS) devices in stores nationwide. Over a period of a few weeks, the hackers stole credit and debit card information from about 40 million customers who shopped at Target stores.

The financial cost of this breach was enormous. Target reported that the breach cost the company $292 million, of which only $90 million was offset by insurance. Beyond financial losses, the breach eroded trust among customers and damaged Target’s reputation.

The nature of the data compromised was primarily financial, affecting customers who had swiped their cards at Target’s POS terminals during the breach. In response to the breach, Target accelerated its program to implement chip-and-PIN card readers in its stores, a much more secure method of processing cards than the traditional swipe method.

Despite the swift response, the incident led to a class-action lawsuit against Target, resulting in a $10 million settlement in 2015. The company also paid an additional $18.5 million settlement to 47 states and the District of Columbia. The Target breach served as a wake-up call for the retail industry about the importance of cybersecurity, leading to significant investments and upgrades in security infrastructure.

5. The Sony Pictures Hack (2014) – A Hollywood Blockbuster Turned Real

In late 2014, a plot straight out of a Hollywood cyber-thriller unfolded in real life. Sony Pictures Entertainment fell prey to an unprecedented cyber attack. This malicious act was allegedly carried out by a group called the “Guardians of Peace,” backed by North Korea, according to the U.S. Federal Bureau of Investigation.

This well-coordinated attack crippled Sony’s network, bringing operations to a standstill. However, the real blow was the theft and subsequent leak of unreleased films, sensitive documents, and personal data of employees. The data compromised ranged from scripts of unaired pilots and confidential emails to personal information, including salaries and social security numbers of employees.

The hack wasn’t confined to Sony Pictures in the United States. It affected their operations globally, causing significant reputational damage and financial losses estimated at $15 million initially, but later, the total cost was speculated to be much higher.

In the aftermath of the attack, Sony Pictures worked diligently to restore their systems and tighten their cybersecurity. The hack had significant implications on Sony’s business, including the cancellation of the theatrical release of the movie “The Interview,” which was cited as a potential motive behind the attack. This incident served as a stark reminder of the vulnerability of even the most established corporations in the face of sophisticated cyber threats.

6. The Home Depot Breach (2014) – A Renovation Nightmare

In 2014, The Home Depot, a leading home improvement retailer, was in dire need of security improvement when it suffered a massive data breach. This attack was orchestrated by an organized crime group that used a variant of the malware used in the Target breach.

Over a span of five months, cybercriminals stealthily siphoned off credit and debit card details from the retailer’s point-of-sale systems. The breach affected around 56 million customers across the United States and Canada, making it one of the most substantial credit card breaches in history.

The fallout was significant, with Home Depot shouldering a financial loss of an estimated $179 million, inclusive of the costs to investigate the breach, provide credit monitoring services for its customers, increase its call center staffing, and pay legal fees.

The breach exposed the financial data of the affected customers, putting them at risk of fraudulent transactions. To prevent a recurrence, Home Depot implemented enhanced encryption in all its U.S. stores, a security measure that scrambles raw card information to make it unreadable to unauthorized users.

In 2016, Home Depot agreed to pay at least $19.5 million to compensate U.S. consumers harmed by the data breach. This incident, along with the Target breach, highlighted the vulnerabilities in point-of-sale systems and underscored the urgency for retailers to upgrade their payment security systems.

7. Ashley Madison Hack (2015) – Shattering Secrets

In the summer of 2015, a hack of a different nature occurred. The target was Ashley Madison, an online dating service marketed to people who are married or in relationships. The hacker group, calling themselves The Impact Team, breached the site’s security, threatening to expose the personal details of the site’s 37 million users unless the site was shut down.

The hackers made good on their threat when Ashley Madison didn’t comply. Names, email addresses, phone numbers, and transaction histories were made public, causing personal scandals and even reportedly leading to suicides.

This attack wasn’t confined to a single region but spanned the globe, impacting users worldwide. The exact financial damage is difficult to quantify, but the reputational cost was immense. Ashley Madison and its parent company, Avid Life Media, faced numerous lawsuits following the breach.

In response to the incident, Ashley Madison beefed up its security measures and took steps to ensure users’ privacy. In 2016, the company agreed to pay $1.6 million to settle charges with the Federal Trade Commission and several states in the US related to the data breach. This incident served as a stark reminder that in the digital world, even the most guarded secrets aren’t completely safe.

8. The WannaCry Ransomware Attack (2017) – A Global Wake-Up Call

In May 2017, a cyber attack of an unprecedented scale spread across the globe. The culprit was WannaCry, a ransomware worm that encrypted users’ data and demanded Bitcoin as ransom. This attack wasn’t the work of an individual or a crime group but was allegedly backed by a nation-state, specifically North Korea, according to the U.S. National Security Agency.

The WannaCry attack infected hundreds of thousands of computers in over 150 countries, impacting individuals, businesses, and even critical infrastructure. The National Health Service (NHS) in the UK was among the most severely affected, causing widespread disruption of healthcare services.

While the ransom demanded from each victim was relatively small, the scale of the attack led to significant financial losses. Estimates suggest that the WannaCry attack could have cost billions globally. However, the true cost extends beyond financial loss, impacting essential services and causing widespread disruption.

The attack was eventually halted thanks to a kill switch activated by a cybersecurity researcher. In the aftermath, organizations worldwide scrambled to patch their systems against the vulnerability that WannaCry had exploited. The attack served as a global wake-up call about the importance of maintaining up-to-date systems and the potential scale and impact of cyber threats.

9. Equifax Data Breach (2017) – A Credit Catastrophe

2017 was also the year of another significant cyber attack, this time targeting Equifax, one of the three largest credit bureaus in the United States. In this case, the perpetrators were cybercriminals who exploited a vulnerability in a website application.

For more than two months, the hackers had access to the personal data of nearly 147 million people. The compromised data was a gold mine for identity thieves, including names, social security numbers, birth dates, addresses, and in some instances, driver’s license numbers.

The breach was not limited to the United States, but also affected customers in Canada and the UK, making it an international incident. The financial fallout was massive, with Equifax reporting that the breach cost them over $1.4 billion, not including the legal fees and expenses related to ongoing litigation.

In response to the breach, Equifax took measures to strengthen its security infrastructure and offered free identity theft protection and credit file monitoring to all U.S. consumers, regardless of whether they were impacted by the breach. In 2019, Equifax agreed to a global settlement with the Federal Trade Commission, the Consumer Financial Protection Bureau, and 50 U.S. states and territories, which included up to $425 million to help people affected by the data breach.

10. SolarWinds Hack (2020) – A Stealthy Cyber Espionage Operation

In 2020, a complex and stealthy cyber espionage operation came to light, known as the SolarWinds hack. The attack was allegedly orchestrated by a nation-state, with U.S. intelligence agencies pointing the finger at Russia.

This sophisticated operation targeted SolarWinds, a software company whose products are used by many Fortune 500 companies and multiple U.S. government agencies. The attackers managed to compromise the company’s software update system and used it to distribute malware, affecting approximately 18,000 customers.

This international incident resulted in unauthorized access to multiple government and corporate networks over several months, compromising a wide range of sensitive information. The exact financial cost is difficult to estimate, but the potential security implications are far-reaching and significant.

In response, SolarWinds and the affected organizations worked closely with law enforcement and intelligence agencies to investigate and mitigate the attack. The incident highlighted the vulnerability of supply chains and the sophistication of modern cyber threats, leading to calls for heightened cybersecurity measures and coordinated responses at the national and international levels.

Conclusion – Your Cyber Safety Matters

Navigating the digital world can sometimes feel like walking through a minefield, as our recap of the worst cyber attacks shows. However, don’t despair; there are practical steps you can take to protect yourself and your data.

Firstly, ensure all your devices are updated regularly. Updates often include patches for security vulnerabilities that hackers can otherwise exploit. Secondly, invest in reliable antivirus software for Windows 11 like Norton, Bitdefender, McAfee, Panda, or Kaspersky. It’s your first line of defense against many types of malware, including those used in high-profile attacks.

Remember, your online safety is a journey, not a destination. Staying informed about the latest threats and best practices in cybersecurity can help you navigate this path more safely. Here are a few trusted resources where you can learn more:

For official reports on the incidents we’ve discussed, the following resources are invaluable:

Cyber threats may seem daunting, but remember, each of us has a crucial role to play in creating a safer digital world. By taking basic precautions and staying informed, you can significantly reduce your risk and navigate the internet with greater confidence and security.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor has tested 39 antivirus programs and 30 VPN services, and holds a Cybersecurity Graduate Certificate from Stanford University.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

You can find him on LinkedIn or contact him here.