Personal Data Leaked From Popular E-mail Service

A leading e-mail service under the country’s second-largest Web portal Daum yesterday suffered a major leak of personal information due to a login error.

Those who logged in Hanmail between 3:40 p.m. and 4:20 p.m. yesterday saw other users’ e-mail inboxes instead of their own, industry experts said yesterday.

This occurred even after users pressed the “refresh” button. Those who logged off and back on also saw the inboxes of random subscribers.

Leaked were the titles of people’s e-mail and the names of recipients and senders, but attached files from the attachment box were also open for download.

The contents of the e-mail, however, were not shown when the e-mail titles were clicked since an error message then appeared.

A similar malfunction also occurred on Daum’s online community service, exposing the list of the online communities a user belonged to.

Daum blocked user access by shutting down its server around 4:20 p.m., 40 minutes after the incident occurred, and resumed its e-mail service around 5 p.m.

“We believe the problem occurred in the process of upgrading Hanmail functions,” a Hanmail source said. “We are looking into the exact cause of the problem and the extent of damage. However, we have tentatively concluded that hackers were not involved in the incident.”

The server for Daum’s customer service center also crashed down due to a flood of inquiries about the malfunction.

Consumer Korea, a civic group advocating consumer rights, said it will receive complaints about Daum’s mishap.

“We have demanded that Daum give us responsible answers on the information leak,” a Consumer Korea member said. “If necessary, we will take legal action.”

imsun@donga.com jhk85@donga.com