Top 9 Cyber Attacks In History

Amol Rangari
3 min readDec 24, 2021

I was reviewing some of the cyber attacks that have occurred since the start of the computer and network age. I decided to write on the top 9 of these attacks according to myself.

Well, lets get the definition of what a cyber attack is then. By definition, Cyber attack is an intentional attempt by a hacker to gain unauthorized access to systems in other to steal data or cause damage to computers.

Cyber Attacks Over the Years

1.The Melissa Virus : In 1999, the Melissa Virus was unleashed unto cyberspace by a programmer named David Lee Smith by sending users a file to be opened in Microsoft Word. The virus caused damage to hundreds of companies at that time including Microsoft. The repairing cost was around $80 Million.

2. NASA Cyber Attack : In 1999, a 15 year old James Jonathan was able to gain unauthorized access and shutdown NASA’s computers for 21 days. Around 1.7M software were downloaded during the attack, which cost the space giant around $41,000 in repairs.

3. The 2007 Estonia Cyber Attack : In April 2007, Estonia witnessed what is “thought” to be the first cyber attack on an entire country, during which about 58 Estonian websites went offline, including the websites of governments, banks and other media outlets.

4. Attack on Sony’s PlayStation Network : A cyber attack on Sony’s PlayStation Network in April 2011 claimed the personal information of about 77M users. This attack cost Sony around $171 million.

5. Cyber Attack on Yahoo : In 2014, Yahoo witnessed one of the biggest cyber attacks of the year when 500M accounts were compromised. However, it is reported that basic information and passwords were stolen, whereas bank information was not, but the attack costed around $350 million.

6. The Biggest Password Leak Yet : It was reported that a compilation of about 8.4B passwords were leaked. This by far is the biggest password leak and is referred to as RockYou2021 in reference to the 2009 data breach of RockYou site that compromised around 32M accounts.

7. Stealing Tens Of Million Of Credit Card Details : T Gonzales, a hacker from Miami, was responsible for one of the biggest fraud case in US history. Gonzales was responsible for sealing tens of millions of credit card and debit card numbers from over 250 financial institutions.

8. The WannaCry Ransomware Cyber Attack : One of the biggest ransomware of all time took place in 2017, when around 200,000 computers were affected in more than 150 countries. This outbreak had a massive impact across several industries and had a global cost of about 6B pounds!

9. Colonial Pipeline Attack : The Colonial Pipeline attack was reportedly carried out by the notorious group, DarkSide, which is allegedly based within Russia. The cybercriminals threatened to leak 100GB of sensitive and confidential data of Pipeline unless they agree to pay $5 Million.

Still cyber attacks are on the rise. These 9 attacks according to me are the toppest so far in history. Which one was your favourite? Leave a comment below on that.

Is there anything I missed? You can add it to the comments and upon review, I’ll add it to the post and tag you :)

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Amol Rangari

I am Cyber Security Expert, Security Researcher and bug hunter