August 28, 2025 - While the virus didn't steal financial information or permanently damage systems, the cleanup and restoration functionality cost an estimated $80 million. This economic impact, paired with the widespread disruption, made it one of the biggest and most notorious cyber attacks in history.

Discover the biggest cyberattacks in history, from ransomware to data breaches. Learn how these 10 shocking cases changed cybersecurity forever.

1 month ago - Shamoon, a modular computer virus, was used in 2012 in an attack on 30,000 Saudi Aramco workstations, causing the company to spend a week restoring their services. Wiper – In December 2011, the malware successfully erased information on hard disks at the Oil Ministry's headquarters. Stuxnet, a malicious computer worm believed to be a jointly built American-Israeli cyber weapon.

Hackers claimed their attack was in retaliation for the Russian Kyivstar cyberattack. December 2023: Russian hackers hit Ukraine’s largest mobile phone provider, Kyivstar, disabling access to its 24 million customers in Ukraine. Hackers claim to have destroyed more than 10,000 computers and 4,000 servers, including cloud storage and backup systems.

August 12, 2025 - The most destructive cyber attack in history is widely considered to be the NotPetya attack of June 2017. Though the primary target was Ukraine, the malware rapidly spread globally, with estimated damage in excess of $10 billion.

September 30, 2025 - Explore the 11 biggest hacker attacks in history highlighting breaches such as the 1999 attack on NASA or cyberattack that shut down an oil processing facility.

This breach stands as one of the largest in Australian history, surpassing previous incidents such as the 2022 Optus hack, which impacted 10 million Australians. 6. Synnovis-NHS Cyber Attack: On June 4, 2024, the NHS in the UK declared a ‘critical incident’. Its pathology services provider, Synnovis, had become victim of a ransomware attack by Qilin Ransomware Gang.

Keep sensitive data and anything ... will do less damage. The biggest cyberattack in history was arguably the Jonathan James attack on NASA and the U.S....

May 21, 2025 - Details included contact information, mortgage ownership, financial histories and whether a household contained a dog or cat enthusiast. Names were not included. All of this was exposed on a publicly accessible AWS S3 storage cache. Protect your data in the cloud with continuous assessment of misconfigurations · Equifax, an American credit company, revealed (first six weeks after the fact), that it had suffered a cyber attack over the course of a number of months.

June 19, 2023 - The Adobe cyber attack was first thought to have breached the data of 2.9 million users. Moreover, it compromised the personal data of up to 38 million users! Adobe claims that only the passwords and credit card information of the first 2.9 million users were compromised, however, the remaining 35.1 million suffered the loss of their passwords and user IDs. In 2014, Yahoo was subject to one of the biggest cyber attacks of the year when 500 million accounts were compromised.

June 16, 2025 - The Top 5 Most Dangerous Cyber Attacks of all Time - Alex ArchondakisThis blog outlines the top 5 most dangerous cyber attacks of all time including The WannaCry Ransomware attack and The Equifax Data Breach and more attacks that have struck history.

May 3, 2022 - ... The data breach of Yahoo is one of the worst and most infamous cases of a known cyberattack and currently holds the record for the most people affected. The first attack occurred in 2013, and many more would continue over the next three years.

Of course, some cyberattacks stand out from the crowd in terms of financial or social damage caused or simply for their sheer audacity. ... Cheater's site gets cheated... ... Yahoo exposes all Three billion users' data twice... ... A series of distributed denial of service (DDoS) attacks significantly disrupted Internet use in North America and parts of Europe in 2016.

February 19, 2025 - They’re subject to debate, but these 39 attacks categorized under OWASP Top 10 would be strong candidates for the title. In October 2023, the British Library suffered a major cyberattack by the Rhysida ransomware group, leading to the exposure of 600GB of sensitive data after a failed ransom demand.

November 15, 2016 - Major cyber crime cases over the years. Results: 7 Items · A Byte Out of History: $10 Million Hack · A Russian’s hacking of a U.S. bank in 1994 may have been the first online bank robbery. More → · Botnet Operation Disabled · Thieves tracked keystrokes on two million infected computers to steal users' information.

In 2017, for example, the Russian cyber military unit Sandworm orchestrated a malware attack that cost global businesses an estimated $1 billion. A few years later, on the other hand, in 2021, hackers breached the system of a water treatment facility in Florida, nearly poisoning a regional water supply by programming a dangerous increase in sodium hydroxide. Read on to find out about some of the most impactful cyberattacks in history.

July 14, 2025 - With the total damage estimated at more than $10 billion, NotPetya is still considered the most destructive and costly cyberattack in history. ... More than 3.6 billion records were exposed when DarkBeam, a digital protection firm, left an Elasticsearch and Kibana interface unprotected. These records contained user emails and passwords from previously reported and non-reported data breaches. ... CL0P Ransomware Gang, also known as TA505, began launching a widespread attack in May 2023 after exploiting a previously unknown SQL injection vulnerability in Progress Software's MOVEit Transfer.