Landmark cyberattacks weren't born from complex zero-day exploits, but from simple, preventable failures in basic security hygiene.
Most catastrophic breaches follow a distressingly simple path. A single weak link, often an overlooked basic security step, creates an entry point for attackers to exploit, leading to widespread compromise.
Analysis of the most notorious incidents reveals a recurring pattern of fundamental oversights. Unpatched systems and weak authentication methods consistently rank as the top entry points for threat actors, proving that mastering the basics is paramount.
Failure to Patch
A known vulnerability in a web application framework was left unpatched for months, allowing attackers to access the personal data of nearly 150 million people.
Failure to Patch
The ransomware worm spread globally by exploiting a Windows vulnerability for which a patch was already available. It crippled systems in hospitals, transport, and government.
Lack of MFA
Attackers gained access using a single compromised password for a VPN account that was not protected by Multi-Factor Authentication, leading to major fuel shortages.
Poor Network Segmentation
A breach that started with a third-party HVAC vendor escalated because the vendor's network access was not properly isolated from Target's critical payment systems.
Insecure Legacy Systems
Attackers dwelled in the Starwood network for four years before being discovered post-acquisition by Marriott. The legacy system lacked modern security controls.
Lack of MFA
A single remote access server without Multi-Factor Authentication served as the entry point for an attack that disrupted the US healthcare system and cost billions.
The direct financial costs of these breaches—from regulatory fines to ransom payments—are staggering. This chart highlights only the publicly disclosed initial figures, which often represent a fraction of the total economic impact including recovery costs and lost revenue.
Beyond financial loss, the human cost is measured in hundreds of millions of compromised personal records. Breaches at consumer-facing companies like First American and Marriott exposed a colossal amount of sensitive data, creating long-lasting risks of identity theft and fraud for individuals.