Yahoo Breach of 500M Accounts Among the Biggest of All-Time

The Yahoo breach of 500 million accounts, which is being blamed on a "state-sponsored actor," was way worse than anyone expected.

The internet company, which is in the process of being sold to Verizon, confirmed it had fallen victim to a hacker in late 2014 in what security experts are saying is believed to be the biggest breach of all time.

"This cycle [of credential spills] is typical, but the scale is pretty astounding," Shuman Ghosemajumder, chief technology officer of Shape Security, a Google Ventures-backed firm, told NBC News.

"Yahoo is such a general website so it represents a cross-section of the worldwide population that could be affected by this," he said. "This really takes the risk up to a new level."

In May, it was revealed that as many as 360 million Myspace usernames, emails and passwords for accounts created before June 11, 2013 may have been stolen by the same hacker who revealed the Yahoo breach last month to Vice's Motherboard. LinkedIn may have also fallen victim in a 2012 hack. Both companies said they required possibly impacted accounts to change their passwords.

Data security expert Timothy Carone, a professor at the University of Notre Dame's Mendoza College of Business, told NBC News these types of breaches can happen to any company.

For Subscribers

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

FOR SUBSCRIBERSCornell rape allegation spotlights stringent New York state laws that have long drawn criticism

FOR SUBSCRIBERSThe debate over AI’s future rages on both coasts

FOR SUBSCRIBERSDecades-old march dispute reignites in Northern Ireland, threatening political crisis

"It is an arms race. Things like this are going to happen to the best in the business," he said. "I don't believe it is because Yahoo has been lax or has not taken this sort of thing seriously -- it could have every easily been someone else."

For Subscribers

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

FOR SUBSCRIBERSCornell rape allegation spotlights stringent New York state laws that have long drawn criticism

FOR SUBSCRIBERSThe debate over AI’s future rages on both coasts

FOR SUBSCRIBERSDecades-old march dispute reignites in Northern Ireland, threatening political crisis

Bob Lord, Yahoo's chief information security officer, confirmed the breach in a statement on Thursday afternoon and said the company was "working closely with law enforcement on this matter."

The stolen account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords and, in some cases, according to Lord, encrypted or unencrypted security questions and answers.