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Most Damaging Security Breaches in Modern History – Opsio

Published: ·Updated: ·Reviewed by Opsio Engineering Team
Fredrik Karlsson

These security breaches not only revealed the severe consequences that these attacks can have, but also alerted businesses to tighten up their security measures and take a more aggressive approach to security.

Yahoo

In the month of March 2017, The FBI indicted a group of 4 people responsible for the ‘spear-phishing email’ that was sent to a Yahoo employee. The hackers used social engineering techniques to access a high-ranking Yahoo employee to break into the systems. The breach allegedly affected around 3 billion accounts.

LinkedIn

A recent victim of a data scraping breach in June of 2021, LinkedIn denied losing any private data of LinkedIn users, but later disclosed that 700 million LinkedIn profiles’ public information was exposed. The data mainly included phone numbers, locations, and social media details.

Facebook

User data of millions, including phone numbers, Facebook IDs, account names were compromised in August 2019. The hackers got into Facebook systems by exploiting a feature that allowed users to be found using phone numbers. The consequences were so severe that CEO, Mark Zuckerberg, had to answer to Federal Investigators and pay a hefty penalty for compromising the privacy of the users.

Kaseya

In July 2021, US tech provider Kaseya was attacked by the REvil ransomware gang which resulted in affecting Kaseya’s supply chain. Around 800-1500 businesses worldwide were threatened as the attack hit roughly 50 managed servicer providers. The authorities and Kaseya officials managed to limit the damage and even apprehended the attackers.

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Acer

Taiwan based computer manufacturer, Acer had received a ransom of USD 50 million from the ransomware gang, REvil. Consequently, the ransomware gang had uploaded confidential information such as financial records onto their website in the dark web. Though Acer reported it to the authorities, it is yet unclear if Acer paid the ransom to the attackers.

Colonial Pipeline Company

One of the largest fuel pipelines in the world had its fuel supply disrupted due to a ransomware attack. The ransomware had infected IT systems and forced the CPC to temporarily shut down. Through further hearings, it was revealed that CPC paid USD 4.4 Million to the attackers so that they could go back online as soon as possible.

Telegram

The messenger app Telegram was hacked in September 2020, and the attackers gained access to email data of cryptocurrency businesses using Signaling System 7(SS7), which is primarily used to hacking mobile networks across the connected world. With previously compromised credentials, the attackers were able to use them and the 2FA codes to log in to the accounts of victims.

Twitter

Even the social media platform and tech giant, Twitter, got attacked by Cyber-criminals, where they had hacked high profile Twitter accounts and composed fraudulent tweets seeking Bitcoin. They hacked into high-profile celebrities and public figures twitter accounts and sent out tweets requesting bitcoin. These tweets were quickly taken down, but they generated over USD 100,000 in a short span of time.

Florida, USA

A cyber-criminal had gained access to the water distribution system of a city, Oldsmar, in Florida, and tried to increase the amount of sodium hydroxide (lye) in its water treatment system. Thankfully, a worker in the treatment plant noticed the abnormality and reversed what could have been a highly dangerous incident.

About the Author

Fredrik Karlsson
Fredrik Karlsson

Group COO & CISO at Opsio

Operational excellence, governance, and information security. Aligns technology, risk, and business outcomes in complex IT environments

Editorial standards: This article was written by a certified practitioner and peer-reviewed by our engineering team. We update content quarterly to ensure technical accuracy. Opsio maintains editorial independence — we recommend solutions based on technical merit, not commercial relationships.