South Korean crypto change Bithumb says it’s “proactively responding” after the nation’s largest cellular community operator, SK Telecom, was hacked.

SK Telecom, which holds almost 50% of South Korea’s telephone service market, says it was attacked on April 19 with a malware an infection that allowed hackers to entry delicate USIM-related buyer data.

This data, which historically contains cellular subscriber id knowledge, authentication keys, community utilization knowledge, and SMS or contacts, might be used for focused surveillance, monitoring, and SIM-swap assaults.

In response, Bithumb has introduced that it “is proactively responding to ensure that you can use our services safely through real-time monitoring of USIM forgery.”

In an announcement issued on Thursday, the change stated, “Bithumb operates an account security enhancement policy to protect our customers’ accounts, and we would like to inform you of damage prevention rules to prevent any possible damage, so please pay special attention.”

In accordance with the announcement, steps taken by Bithumb embody USIM forgery monitoring, strengthening its buyer account safety, recommending customers signal up for a “USIM protection service,” and repeatedly checking SK Telecom notices.

It additionally means that customers substitute their SIM playing cards instantly in the event that they “have been confirmed as a ‘target of information leak.’”