6 Largest Cyber Attacks in History


Some of the largest cyber attacks in history have caused massive damage and disruption around the world. As more aspects of society and critical infrastructure become connected to the internet, the impact of major cyber attacks continues to grow. Here is an overview of several of the most significant cyber attacks on record.

1) WannaCry Ransomware (2017)

In May 2017, a massive ransomware attack known as WannaCry spread to over 200,000 computer systems across 150 countries. The attack encrypted files on infected systems and demanded ransom payments in Bitcoin to decrypt them.

WannaCry particularly affected computers running outdated versions of Microsoft Windows by exploiting a vulnerability that had been discovered and built into hacking tools allegedly developed by the NSA. Major disruptions were reported by several organisations worldwide, including the UK’s National Health Service, Spain’s Telef├│nica telecommunications company, and Germany’s Deutsche Bahn railway operator.

Total financial losses from the WannaCry attack were estimated to exceed $4 billion.

2) NotPetya Attack (2017)

In June 2017, organisations around the world were hit by another destructive ransomware attack known as NotPetya. It is considered one of the most damaging cyber attacks to date, causing over $10 billion in damages.

NotPetya targeted Microsoft Windows systems, spreading rapidly through networks by exploiting the same vulnerability as WannaCry. Major multinational companies were severely impacted, including shipping company Maersk, pharmaceutical giant Merck, and the French construction company Saint-Gobain.

The attack also crippled computer systems across Ukraine where it is believed to have originated. Evidence links NotPetya to the Russian military.

3) Stuxnet (2010)

The Stuxnet worm, uncovered in 2010, was a sophisticated cyber weapon used to target and damage Iran’s nuclear enrichment facilities. Stuxnet was specifically designed to spread via removable drives on Windows machines at the Natanz plant, causing centrifuges to spin out of control and self-destruct. Because the malware only caused damage under very specific circumstances, the effects of the attack went undetected for months.

Stuxnet temporarily crippled Iran’s capacity to develop nuclear material and caused about one-fifth of centrifuges to be destroyed. The virus is widely attributed as a joint effort by U.S. and Israeli intelligence agencies.

4) Yahoo Breach (2013-2014)

In what is considered the largest data breach in history, all 3 billion Yahoo user accounts were compromised by a 2013 breach that went undetected for three years. The attackers, believed to be state-sponsored hackers from Russia, stole names, email addresses, phone numbers, birthdates, and encrypted passwords from Yahoo’s user database.

A separate 2014 intrusion also allowed hackers to gain the account keys needed to access the private information of over 500 million accounts. The massive Yahoo breach highlighted the vast amounts of sensitive user data that tech firms have access to and their vulnerability to sophisticated cyber attacks.

5) Sony Pictures Hack (2014)

In November 2014, a hacker group calling itself the “Guardians of Peace” carried out a devastating cyber attack against Sony Pictures in retaliation for the planned release of the comedy film The Interview. The hackers stole and released over 100 terabytes of confidential data including upcoming film scripts, employee salaries, financial records, and thousands of private emails. They also wiped over half of Sony Pictures’ global network.

U.S. intelligence officials attributed the attack to North Korean state-sponsored hackers who were enraged by the film’s depiction of a plot to assassinate Kim Jong Un. The costly Sony Pictures hack demonstrated how cyber attacks could now be used as strategic weapons against media organizations.

6) Equifax Breach (2017)

The credit reporting agency Equifax announced in September 2017 that the personal information of over 145 million Americans had been exposed in a massive data breach. The attackers exploited a security flaw to gain access to Equifax systems and stole sensitive customer information including Social Security numbers, birthdates, addresses, and some driver’s license numbers.

Because the breach involved data that rarely changes over a person’s lifetime, it created serious risks of identity theft for millions of people. Equifax had failed to patch the software vulnerability that hackers were able to exploit. Their massive data stores coupled with lax security made Equifax an ideal target.

How Organisations Can Protect Against Cyberattacks

There are several key steps organisations can take to improve network reliability and reduce vulnerabilities.

  • Keep all software up-to-date with the latest patches to ensure known security holes are addressed.
  • Install high-quality firewall, antivirus, and intrusion detection systems to monitor traffic and block malicious attacks.
  • Use strong encryption and multi-factor authentication to secure access.
  • Provide cybersecurity training to employees to minimise risky behavior.
  • Restrict administrator privileges and segment networks to limit access.
  • Conduct regular vulnerability scans and penetration testing to identify weaknesses.

With proper cybersecurity measures and awareness, companies can substantially reduce their exposure to cyber threats exploiting network vulnerabilities.

These major cyber attacks represent the wide range and potential impact of vulnerabilities that organisations and customers now face in an increasingly interconnected world. As worldwide connectivity grows, cyber security strategies and policies will need to evolve to protect against emerging digital threats. The costs of data breaches and network disruptions will also continue to rise dramatically.


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