The hacker said the Yahoo database came from a Russian group who also breached LinkedIn and Myspace. Yahoo users might want to reset their passwords. A hacker claims to have stolen the login information for 200 million Yahoo accounts and is selling them on the black market.The stolen records are up for sale on TheRealDeal, a darknet marketplace that offers illegal goods. For 3 bitcoins, or US$1,824, anyone can buy them.The hacker, known as peace_of_mind, has claimed to have previously sold login credentials for LinkedIn and Tumblr users.In a brief message, peace_of_mind said the Yahoo database came from a Russian group that breached LinkedIn and Tumblr, in addition to MySpace. In the case of the Yahoo accounts, the database “most likely” comes from 2012, the hacker said. Copies of the stolen Yahoo database have already been bought, peace_of_mind added.On Monday, Yahoo said it was “aware” that the stolen database was on sale, but it neither confirmed nor denied that the records were real. “Our security team is working to determine the facts,” the company said in an email.Back in 2012, Yahoo reported a breach, but of only 450,000 accounts. A hacking group called D33ds Company had claimed responsibility, but Yahoo said that most of the stolen passwords were invalid.It’s unclear if that hack is connected with this sale of 200 million accounts. Other security researchers have also noticed a Russian hacker known as “the Collector” selling tens of millions of email logins from Yahoo, Gmail and Hotmail. Peace_of_mind has posted a sample of the stolen Yahoo database, which includes user email addresses, along with passwords that have been hashed using the MD5 algorithm.Those passwords could easily be cracked using a MD5 decrypter available online. The database also contains backup email addresses, as well as the users’ birth dates.IDG News Service tried several email addresses from the stolen records and noticed that Yahoo’s login page recognized them and then asked for a password. However, other emails addresses were no longer valid. Although Yahoo hasn’t confirmed the breach, users should still change their passwords, said Adam Levin, chairman of security firm IDT911, in an email.In addition, users should make sure they aren’t using the same passwords across Internet accounts, he added. Related content feature Top cybersecurity M&A deals for 2023 Fears of recession, rising interest rates, mass tech layoffs, and conservative spending trends are likely to make dealmakers cautious, but an ever-increasing need to defend against bigger and faster attacks will likely keep M&A activity steady in By CSO Staff Sep 22, 2023 24 mins Mergers and Acquisitions Mergers and Acquisitions Mergers and Acquisitions brandpost Unmasking ransomware threat clusters: Why it matters to defenders Similar patterns of behavior among ransomware treat groups can help security teams better understand and prepare for attacks By Joan Goodchild Sep 21, 2023 3 mins Cybercrime news analysis China’s offensive cyber operations support “soft power” agenda in Africa Researchers track Chinese cyber espionage intrusions targeting African industrial sectors. By Michael Hill Sep 21, 2023 5 mins Advanced Persistent Threats Cyberattacks Critical Infrastructure brandpost Proactive OT security requires visibility + prevention You cannot protect your operation by simply watching and waiting. It is essential to have a defense-in-depth approach. By Austen Byers Sep 21, 2023 4 mins Security Podcasts Videos Resources Events SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe