How was the IELTS face-to-face lecture leaked?

Do you want to ask how the IELTS interview materials were leaked? The reason for this is the following：

According to the existing data, the leakage of IELTS interview data is caused by improper data storage strategy and security control. Unencrypted data, unclassified data and lack of security audit of data may all lead to the disclosure of IELTS interview materials.

IELTS is an international English test founded by the Examination Committee of Cambridge University, England, which is mainly used to test the English level of students from non-English-speaking countries.