A joint public-private investigation team has spent the past 500 days probing cyber breaches that hit South Korea’s telecommunications and broadcasting industry. Its investigations covered SK Telecom’s USIM hacking incident, KT’s illegal femtocell-linked case and Tving’s account information leak, and it was also deployed to a Coupang breach. The team found repeated shortcomings in basic security practices such as account and authentication management, log retention and abnormal-sign detection, and identified cases of late or missing incident reporting.

Tving suffered a hacking incident that leaked information on 39.54 million user accounts, effectively all accounts on the platform, an investigation team said on Wednesday. Attackers stole a developer access key, penetrated the development environment and then accessed production systems to extract personal data. Leaked data included IDs, encrypted passwords and other personal information, while 361 development projects containing source code were also taken. No confirmed misuse has been found so far.