Three Seoul international schools were still using PowerSchool’s student information system as of Nov. 1, 2026, after 15,666 records linked to the schools were compromised, Maeil Business Newspaper reported, citing Seoul education-office data provided to council member Yun Yu-jin.
Maeil reported that the records were compromised in 2025 in connection with a cyberattack on PowerSchool. Its reported breakdown was 8,000 records at Korea International School, 6,666 at Seoul Foreign School and 1,000 at Yongsan International School of Seoul. The count represents records, not a confirmed number of unique people.
Maeil said the records included identifying details such as names and birth dates, contact information including email, home addresses and phone numbers, students’ graduation years, and health-related details. CrowdStrike, which PowerSchool hired to investigate, traced the removal of student and teacher table data to Dec. 19-23, 2024, UTC. The reports do not explain why Maeil dates the Seoul records’ compromise to 2025 while CrowdStrike places the data exfiltration in 2024.
CrowdStrike said the attacker used stolen support credentials and maintenance functions in PowerSource, PowerSchool’s customer-support portal, to reach student information system data. Investigators found no evidence of malware or access at the system layer. They also found no sign that customer IT environments outside PowerSource and the student information system were compromised.
Maeil reported that Seoul’s education office cited foreign schools’ inability to use South Korea’s National Education Information System as a barrier to applying domestic privacy guidance uniformly. The office reviewed the three schools’ practices and sent caution notices, Maeil said. It requested self-assessment forms in January 2026 and held privacy training in February; nine of Seoul’s 16 foreign schools did not attend.
The same education-office data put compromised records across Seoul primary, middle and high schools at about 27,000 from 2022 through September 2026, Maeil reported. The three international schools accounted for about 60% of that figure. The Korea Herald reported that the schools had not replied before its publication deadline to questions about outside security reviews or added safeguards.
