Chinese video streaming platform AcFun revealed shortly after midnight of June 13 that hackers had stolen data of tens of thousands of user. The company apologized for the breach and admitted that the leak was due to insufficient precautions to secure the platform.

AcFun asked users to change their passwords, especially those who hadn’t logged in the platform since July 7, 2017 and also those whose pervious passwords were weak.

According to the company, the affected data include user IDs, nicknames, and passwords that had been stored on the company’s encrypted servers.

After the hack, AcFun said they had notified users within the platform and across Weibo, WeChat, SMS and other public forums. The company also set up a security task force of internal and external technical experts to investigate the breach and improve cybersecurity.

AcFun was founded in 2007 and is famous for animation, comic and game related content. Although less known than its Nasdaq-listed rival Bilibili, AcFun was China’s first video platform that features real-time commentary subtitles that can overlay the video.

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AcFun was acquired by Kuaishou, one of China’s biggest short video platform, on June 5, after a temporary shut-down in early February due to lack of funds. According to previous media reports, the company’s losses continued to mount in recent years and reached RMB 146 million in the first 9 months of 2016.

Before the February shut-down, the platform was closed for three days due to unspecified reasons in November 2017. The company blamed cyber-attack for paralyzing their services, but online discussions pointed out the company was having internal issues regarding turbulence among management personnel, regulatory punishments and a big loss of users.