Information on subscribers to Seoul city’s public bike-sharing system, Ttareungi, has been compromised in a recently discovered data leak. 

According to the Seoul-based Yonhap News Agency on Friday, the four-and-a-half million leaked items of data include names, phone numbers, dates of birth and home addresses. 

Police believe the breach is the result of a hacking attack and are tracking the source and path of the leak. 

Currently, the number of Ttareungi subscribers is estimated at around five million. 

Police learned of the information leak while investigating another case and conveyed their findings to the Seoul Facilities Corporation, which manages the public bikes. 

An official with the Seoul Metropolitan Government said the city government suspects the data may have been leaked in April 2024, when a series of distributed denial-of-service attacks was detected. 

The official said the city has not received any reports of damage so far.