Hackers Used AI Agents to Raid a Megachurch's Database, Exposing 850,000 Members

Yoido Full Gospel Church, once listed by Guinness as the worlds largest congregation, disclosed that personal information tied to about 850,000 members may have been taken in a suspected breach. The churchs initial examination identified names, dates of birth and a change log covering edits members made to their records. That log included 2,629 changes to resident registration numbers, 3,964 phone number updates and 7,202 address changes.

South Koreas internet security agency, KISA, alerted the church to the suspected breach on Tuesday, after which the church cut external access to its systems, reset server passwords and began notifying potentially affected members. Yoido said it will replace its firewall and hire outside security firms to search for remaining vulnerabilities.

Cybersecurity company Oasis Security said it located the churches data on an overseas server while tracing internet addresses linked to suspected attacks. Alongside the stolen records, Oasis found attack logs and account details tied to both Yoido and Sarang Church. The logs included references to AI sub-agents — helper programs launched by an AI model to handle parts of a task — and long reports that appeared to be machine-written, though the firm and the churches said the exact role of AI in the intrusions is still unclear.

A second Seoul megachurch, Sarang Church, reported a smaller loss: roughly 89,000 member records and 286 employee records, including the senior pastors. Authorities and the churches are investigating when the thefts occurred; Oasiss findings suggest data may have been taken in August. The developments follow separate suspected AI-assisted breaches at South Korean banks; President Lee Jae Myung has said AI is believed to have been used in recent attacks, and reports indicate about 25,000 Shinhan Bank customers had personal and limited financial data exposed, prompting a regulators emergency inspection.