South Korean credit card firms are pushing to tighten their internal control systems as part of their efforts to brace against potential data leaks, sources said Tuesday. The move comes on the heels of a spate of data leaks in the local credit card industry. In the latest episode, Samsung Card Co. recently called on police to investigate an employee about an alleged leakage of customer data, including their names and mobile phone numbers. In April, the personal information of some 1.8 million Hyundai Capital Services Inc. customers was compromised in a hacking attack. Samsung Card plans to tighten its security system and educate employees on managing customer information. The company has already established a system that blocks any illegal transfer of information, according to the sources. Hyundai Card Co., an affiliate of Hyundai Capital, blocks employees from using uncertified laptops and personal computers, and imposes the highest level of penalty to employees who breach security rules. Other industry players such as Shinhan Card Co., Hana SK Card Co. and Lotte Card Co. have also stepped up security measures such as storing customer data in automated encoding systems and operating information security teams. Despite these efforts, the recent data leak at Samsung Card has raised concerns that card firm employees may be capable of leaking customer information. \"Since the Hyundai Capital hacking incident, the industry is stepping up efforts to tighten security. But it seems that company officials can always attempt to leak customer information if they make up their mind to do so,\" said an official, asking not to be named.