Daily Tech Snippet: Thursday, December 15

• Yahoo Says 1 Billion User Accounts Were Hacked: Yahoo, already reeling from its September disclosure that 500 million user accounts had been hacked in 2014, disclosed Wednesday that a different attack in 2013 compromised more than 1 billion accounts. The two attacks are the largest known security breaches of one company’s computer network. The newly disclosed 2013 attack involved sensitive user information, including names, telephone numbers, dates of birth, encrypted passwords and unencrypted security questions that could be used to reset a password. Yahoo said it is forcing all of the affected users to change their passwords and it is invalidating unencrypted security questions — steps that it declined to take in September. It is unclear how many Yahoo users were affected by both attacks. The internet company has more than 1 billion active users, but it is not clear how many inactive accounts were hacked. Yahoo said it discovered the larger hacking after analyzing data files, provided by law enforcement, that an unnamed third party had claimed contained Yahoo information.

• Meitu Makes Muted Debut in H.K.’s Biggest Tech IPO Since 2007: Chinese selfie-apps developer Meitu Inc. stood little changed from its offer price Thursday, a less-than-stellar debut for the biggest initial public offering since the start of a program that made it easier for mainland investors to buy and sell stocks in Hong Kong. Meitu’s IPO was also the biggest coming-out party for a tech company since 2007, when Alibaba.com Ltd. listed. Its shares stood at HK$8.50 at 9:49 a.m. local time, unchanged from an offer price that was already at the bottom of a marketed range. Meitu now has a valuation of HK$35.9 billion ($4.6 billion). The company, which runs apps including Meitu, Meipai and BeautyPlus, is ratcheting up a presence in overseas markets to lure more people beyond the existing 456 million monthly active users. Beauty Plus currently has more than 160 million users including in Japan, Indonesia and India. It will develop more localized features for people in the U.S., including tools that make people look tanned in their photos, said Cai.

• The California DMV says Uber has to stop operating its self-driving cars in SF:  The agency said it will have to take legal action otherwise. Also, an Uber self-driving car ran a red light on its first day in operation.