20 Biggest Cyber Attacks in History

Tales of cyber chaos from the dark web!

Over the years, we have all seen good progress in the field of technology, integration of AI, and shift of focus towards data privacy and security. Yet, the frequency of cyber-attacks has turned out to be a major challenge to global cybersecurity efforts.

Throughout history, there have been some major cyber attacks that have impacted not only people but also multi-dollar corporations and governments in an instant.

In today’s blog, we will discuss some of the most deliberate and malicious attempts that have targeted users, compromised confidential systems, and caused substantial financial losses and reputational damage for organizations.

Biggest Cyber Attacks in History

Most Notorious Cyber Attacks in History

Cyber attacks can be of many forms, such as Malware attacks, Phishing, Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) attacks, SQL injection, and many more. 

Such attacks target various entities like government agencies, businesses, educational institutions, and individuals.

Ranging from large-scale data breaches to sophisticated ransomware attacks, the history of cyber attacks is filled with notable incidents that have reshaped the way we perceive cybersecurity. Some of them are:

1. The Melissa Virus (1999)

One of the earliest cyberattacks that highlighted the importance of digital security was the Melissa Virus.

In 1999, programmer David Lee Smith breached an AOL account and used it to distribute a file on the internet as email attachments that offered access to numerous passwords for fee-based adult websites. However, when users downloaded the document, it released a virus onto their computers.

  • It caused substantial damage to multiple users and companies, including Microsoft.
  • Although cybersecurity measures managed to contain the virus quickly, complete eradication of it took considerable time.
  • Its collective impact of the attack was estimated to amount to approximately $80 million.

2. NASA Cyber Attack (1999)

In 1999, NASA experienced a cyber security breach that resulted in the unauthorized access and shutdown of its computer systems for around 21 days.

  • During the attack, around 1.7 million pieces of software were downloaded.
  • Repair costs for the space agency after the incident are estimated at around $41,000.

However, what made it notable was not just the financial implications but also the perpetrator behind it.

Following this attack, a fifteen-year-old computer hacker admitted guilt and was sentenced to six months in jail. As part of his sentence, the teenager was mandated to write letters of apology to both NASA administrators and the secretary of defense.

Also Read: How to Prevent Ransomware Attacks

3. Estonia Cyber Attack (2007)

In 2007, Estonia suffered the first cyber attack targeting an entire nation. During this incident, around 58 Estonian websites, including those of government agencies, media organizations, and banks, were taken offline.

  • It was a Distributed Denial of Service (DDoS) attack, which overwhelmed Estonian servers and utilized zombie computers to magnify its impact.
  • According to various analyses of this digital event, the attack stemmed from a political dispute regarding the relocation of a specific group to the outskirts of a city. 
  • It is estimated that the incident incurred costs of around $1 million.

4. Heartland Payment Systems (2009)

In early 2009, Heartland Payment Systems informed that its systems were breached in 2008, which exposed the credited and debit card data of over 130 million customers and more than 650 financial service companies.

In response to the breach, Visa temporarily removed Heartland from its systems until the company could confirm its compliance with PCI DSS standards.

Additionally, Heartland implemented encryption for its entire account information system, introducing a new standard of security for the card processing industry.

5. China’s Google Attacks (2009)

In 2009, Chinese humanitarian activists became the targets of a series of espionage hacker attacks. To initiate this, the hackers accessed their Google accounts and tracked their communications. Account malfunctions alerted the targeted users to the growing problem.

  • After a deeper investigation, it was revealed that the hackers also tracked people in several countries.
  • The infiltration likely occurred due to a combination of phishing and malware.

One thing for sure is that this cyber attack event in history shows why it’s so important to identify and report any suspicious occurrences with any online service.

Also Read: What is the Role of Artificial Intelligence in Cyber Security?

6. Sony’s PlayStation Network Hack (2011)

Security professionals and gamers recall this incident as one of the most significant data breaches at the time in 2011.

  • It compromised the personal data of over 77 million accounts and prompted nearly a month-long shutdown of the network.
  • As a result of the attack, Sony had to close down the PlayStation Network for 23 days, incurring an estimated loss of $171 million.

Even though they never found out about the hackers, Sony provided people affected by the breach a free month of their premium service. Additionally, they also made a new insurance policy for all users to protect against identity theft, worth $1 million.

7. Target Security Breach (2013)

Target experienced one of the largest data breaches in history in December 2013. Cybercriminals hacked into Target’s systems and stole more than 40 million credit and debit card information, along with 70 million customer records.

  • It was found that the attack originated from a third-party vendor who had remote access to Target’s network.
  • In response, Target shut down its point-of-sale systems on December 19 and 20 and offered free credit monitoring and theft protection services to affected individuals.
  • Four years later, in 2017, Target settled for $18.5 million with multiple states.

8. Adobe Cyber Attack (2013)

In early October 2013, Adobe announced that hackers had accessed nearly 3 million encrypted customer credit card records and login details for an unspecified number of user accounts.

  • Some days later, Adobe learned that the breach included IDs, 150 million encrypted usernames, and hashed password pairs – active users.
  • Further investigation uncovered that the breach compromised customer names, passwords, and debit/credit card information.
  • In August 2015, Adobe had to pay users $1.1 million in legal fees and a hidden sum to settle allegations of violating the Customer Records Act and engaging in unfair business practices.

Also Read: Top 10 Tech Embarrassments 2023

9. Cyber Attack on Yahoo (2013-2014)

Yahoo experienced two massive data breaches in 2013 and 2014. Considered one of the biggest cyber attacks in history, this breach impacted all 3 billion Yahoo user accounts. However, the most concerning aspect is that Yahoo did not disclose these breaches until 2016.

  • 2014 breach was set up by a Russian hacker group, who initiated the attack by sending a spear-phishing email to a Yahoo employee.
  • With just one click from that employee, the hackers gained entry into Yahoo’s network, allowing them to access user names, email addresses, security questions and answers, telephone numbers, and other sensitive information.

10. Snapchat Users’ Personal Information Leaked (2015)

Snapchat, the messaging app service faced a significant breach in 2015, that revealed the lack of anonymity it promised.

Hackers disclosed the usernames, phone numbers, and locations of 4.6 million accounts, causing distress among many Snapchat users, particularly those who shared sensitive content through the app.

Reportedly, hackers had notified Snapchat about the vulnerability beforehand, but the company failed to take action. While users didn’t suffer financial losses, it took the company more than a year to recuperate from the aftermath of the incident.

Also Read: Benefits of AI in Cyber Security: Use Cases and Examples

11. Ukraine’s Power Grid Attack (2015)

In December 2015, Ukraine’s power grid fell victim to a cyberattack, resulting in over 200,000 people losing electricity for several hours

It was found to be initiated by a Russian-linked hacker group named SandWorm and involved the deployment of BlackEnergy malware, along with KillDisk and a VPNFilter attack framework.

12. WannaCry Ransomware Attack (2017)

In May 2017, WannaCry took advantage of a security vulnerability in the Microsoft Windows operating system known as EternalBlue to spread rapidly across networks. Once a computer was infected, WannaCry encrypted the files and demanded ransom payments in Bitcoin to unlock the system.

  • Initially, the ransom amount was $300, which increased over time.
  • It was found that the ransomware infected more than 230,000 computers across 150 countries.
  • Among the victims were notable organizations such as the UK’s National Health Service (NHS), FedEx, Nissan, and Honda. 

As this vulnerability was unknown to Microsoft, and no patch had been released for it at the time.

Also Read: How to Prevent Ransomware Attacks

13. Equifax Data Breach (2017)

Equifax, a credit reporting agency in the U.S., reported a data breach that affected over 147 million American consumers, which represented more than 40 percent of their population.

  • It occurred between May and July 2017, and exposed names, addresses, dates of birth, Social Security numbers, driver’s license numbers, and approximately 200,000 credit card numbers.
  • It was found that the breach was due to a vulnerability in Equifax’s web application firewall, which allowed attackers to infiltrate Equifax’s systems and steal personal information from consumers.

Following the breach, Equifax faced a fine of $575 million from the Federal Trade Commission, the Consumer Financial Protection Bureau, and 50 states and territories for its involvement in the data breach.

14. NotPetya Ransomware Attack (2017)

In 2017, the NotPetya ransomware impacted over 12,500 computers. It targeted computers running on Microsoft Windows and not only it caused data encryption for ransom, but it also rendered computers completely inoperable.

  • NotPetya also erased data from major global enterprises, such as leading shipping firms FedEx and Maersk, Russian oil and gas giant Rosneft, and British advertising company WPP.
  • FedEx reported losses of $300 million due to the attack, with one of its subsidiaries forced to halt operations.

Also Read: What is Bot Attacks?

15. Cyber Attack on Marriott Hotels (2018)

In September 2018, Marriott International revealed that sensitive details of approximately half a million Starwood Preferred Guests including names, email addresses, phone numbers, passport numbers, account details, DOB, gender, arrival and departure information, reservation dates, and more have been exposed following a cyberattack on its systems.

Ultimately, the company faced a fine of £18.4 million by the UK Information Commissioner’s Office (ICO) in 2020 for its failure to adequately safeguard customers’ data.

16. Singapore SingHealth Cyberattack (2018)

In 2018, Singapore faced its biggest cyber attack ever in history, when the personal information of 1.5 million SingHealth patients was compromised.

  • It exposed names, addresses, national identification numbers, as well as details about patients’ diagnoses and medications.
  • Notably, the breach also included the theft of personal data belonging to Prime Minister Lee Hsien Loong, drawing global attention and highlighting the seriousness of cyber threats confronting Singapore.

As a penalty, the Integrated Health Information Systems (IHiS) and SingHealth were fined $750,000 and $250,000, respectively, by the Personal Data Protection Commission (PDPC).

17. Colonial Pipeline Ransomware Attack (2021)

In May 2021, Colonial Pipeline faced a critical situation when it had to halt all operations along the East Coast to contain the spread of ransomware.

  • It was found that the attack, orchestrated by a Russian hacking group known as DarkSide, compromised the pipeline’s operational technology systems.
  • They encrypted the company’s files and demanded a ransom of 75 BTC, equivalent to approximately $4.4 million at the time, in exchange for the decryption key.

Initially, Colonial Pipeline resisted paying the ransom, but due to the prolonged disruption to its operations, it eventually relented and paid the ransom to regain control of its systems.

Also Read: Top 10 Dangerous Websites List (2024)

18. LinkedIn (2021)

In June 2021, LinkedIn, faced a significant data exposure event when information linked to 700 million of its users surfaced on a dark web forum. It affected more than 90% of its user base.

Later they found that the data was posted by a hacker known as God User, who used data scraping techniques to exploit LinkedIn’s and other platforms’ APIs.

Initially, the hacker released a dataset containing details of approximately 500 million users. Later, they claimed to be selling the full database of 700 million customers.

19. RockYou2021 Password Leak

It is the largest known collection of stolen passwords to date which included a staggering 8.4 billion leaked passwords.

The hacker, whose identity remains undisclosed, dubbed the compilation of passwords RockYou2021, a reference to the 2009 RockYou data breach where over 32 million user passwords were compromised. He shared a 100GB text file containing 8.4 billion password entries, along with data from previous breaches.

Also Read: How to Identify and Protect Yourself from an Unsafe Website

20. Uber Cyber-Attack (2022)

In September 2022, Uber fell victim to a cyberattack, compromising the personal information of over 77,000 of its employees including their full names, email addresses, corporate reports, driver’s licenses, and IT asset information. Severity of the leak nearly led to the complete shutdown of Uber’s systems.

  • Uber has attributed the attack to the hacker group Lapsus$.
  • Investigation reports say that the breach originated when the hackers obtained access to an Uber employee’s device through a phishing email and acquired the credentials to breach the company’s internal systems.

That is it for the blog and these were some of the biggest cyber attacks in history.

Learning from it, it’s high time we develop better strategies to protect ourselves against future threats in the ever-evolving internet era.

Share your thoughts in the comments and stay tuned to TechCult for more interesting blogs.

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