A joint government-civilian team investigating the hacking incident at SK Telecom(SKT) in April has submitted a report to the National Assembly blaming the mobile carrier’s negligence for the resulting data breach.

In the report, issued Friday after a two-month probe, the team under the science ministry said an inspection of some 40-thousand servers found 33 types of malware in 28 servers.

It said one of those was developed by the China-based hacking group Red Menshen, while another type of malware not linked to the hacking incident was also discovered.

The team concluded that SKT’s failure to properly handle a previous malware incident in 2022, such as not reporting it to the ministry, caused the latest hacking incident and said the company will face a penalty.

Citing SKT’s failure to take due precautions, the team said subscribers wishing to change mobile carriers can be exempted from penalties for breach of contract.