The 2017 Equifax data breach was one of the largest and most damaging data hacks in history, affecting over 147 million people. Hackers exploited a vulnerability in Equifax's website software to access sensitive information, including Social Security numbers, birth dates, and addresses. The breach was not detected until months after the attack, allowing hackers to siphon off data undetected. Equifax's delayed response and lack of proper security measures exposed a major weakness in how consumer data is handled. This breach led to lawsuits, financial penalties, and a massive loss of consumer trust. The Equifax hack remains a major example of how tech companies must be vigilant about cybersecurity.