Largest cyberattacks on servers in history

Considered the largest data breach in internet history by the number of accounts affected, these attacks demonstrated the massive scale of server compromises. They had long-term consequences for user data security.

This massive data leak exposed over 4 billion personal records, making it one of the largest and most recent data leaks. It highlights the risks associated with unsecured databases and the potential for intentional data gathering.

A very recent and catastrophic data breach, it exposed 1.5 billion records due to an unsecured database. This incident highlights the vast amount of personal and financial information vulnerable to misconfigurations.

This was a significant supply chain attack, impacting 94 million users and over 2,500 businesses. It demonstrated the ripple effect of compromising widely used software for secure file transfers.

This massive compilation of 16 billion login credentials from various server compromises is considered a historic data leak. It has global reach and significant potential for industrial-scale credential stuffing and account takeover attacks.

This was the largest SaaS supply chain breach, compromising OAuth tokens and sensitive information across hundreds of global organizations. It highlights the growing threat of attacks targeting cloud-based services and their interconnected applications.

This significant breach impacted a major software company and its numerous clients, exfiltrating 570 GB of data from internal repositories. It showcases the risks associated with code repositories and sensitive client data stored on servers.

This attack forced the shutdown of the largest oil pipeline system in the United States, disrupting gasoline supply. It is significant for being the largest attack on critical infrastructure in the US, demonstrating severe real-world consequences.

The widespread exploitation of the Log4J vulnerability represents one of the most significant server-side threats in recent memory. Its pervasive nature allowed attackers to compromise hundreds of millions of devices globally.

This breach was particularly concerning due to the highly sensitive nature of the data stolen from a major credit-reporting agency, impacting 143 to 159 million people's financial identities. It was caused by a failure to patch a known server vulnerability.

This global ransomware worm encrypted data on over 200,000 computers in 150 countries, showcasing the devastating impact of fast-spreading ransomware. It affected numerous organizations and their servers worldwide.

Considered one of the most destructive cyberattacks, NotPetya caused over $10 billion in damages by encrypting and wiping files. It demonstrated the potential for 'wiperware' to cause widespread operational disruption and economic damage by targeting servers.

A very recent cyberattack in 2026, this incident demonstrates ongoing threats to critical sectors like healthcare. It involved data theft and wiping of Windows-based devices, including access to Active Directory Services.

A very recent data breach in early 2026, this incident exposed personal and health-related data from 2.7 million people. It emphasizes the critical importance of securing APIs, which can serve as weak links to server-side data.

Another very recent event from early 2026, this leak by the ShinyHunters group affected 10 million records from Match dating apps. It shows that large-scale data leaks from server compromises continue to be a significant threat to consumer-facing platforms.

A recent large-scale cyberattack on a major technology company, this incident affected as many as 49 million customers. It demonstrates the ongoing vulnerability of corporate systems and the potential for insider or partner account compromises to lead to significant data exfiltration from servers.