The state financial regulator urged financial companies to be mindful of illegal transaction attempts following a hacking incident involving the potential leak of subscriber information at the nation’s leading mobile carrier, SK Telecom.

In a document distributed to financial firms on Thursday, the Financial Supervisory Service(FSS) advised them to consider additional authentication measures for financial services, as SK Telecom’s universal subscriber identity module(USIM) data had been leaked. 

The regulator suggested reinforced monitoring of mobile financial apps that collect device information through additional authentication or a fraud detection system (FDS). 

The FSS also called on the companies to immediately report on illegal financial transactions or other abnormalities in line with the Electronic Financial Transactions Act.

Some insurance companies, including KB Life Insurance and NongHyup Life Insurance, have suspended or plan to suspend authentication via SK Telecom as a proactive measure against further leaks.