SEOUL, May 19 (Yonhap) -- An unidentified hacker has broken into the computer system of a small South Korean brokerage house to steal the firm's customer data, the financial regulator said Thursday, adding concerns over financial firms' computer security maintenance.

   The Financial Supervisory Service (FSS) said the hacker infiltrated the computer server of Leading Investment & Securities Co. and stole 12,000 customers' personal data last week. The stolen data includes their names, social security numbers, addresses and phone numbers, it said.

   The hacker reportedly demanded money through an e-mail, and Leading Investment & Securities reported it to police.

   The FSS said the brokerage house is responsible for its lax database maintenance, which was mainly at fault in the hacking attack.

   The FSS launched a three-day inspection on the securities firm following the attack to determine whether the firm maintained adequate computer security measures to prevent such an infiltration, the regulator said.

   "Through the inspection, we found that the firm's weak personal data management system made such information vulnerable to a hacking attack," an FSS official said.

   The latest hacking incident came on the heels of similar attacks on bigger financial companies. The FSS decided Wednesday to punish top consumer finance firm Hyundai Capital Services Inc. for lax computer system maintenance, which was at fault in the hacking of 1.75 million customers' personal information in March.

   Another hacker infiltration crippled the National Agricultural Cooperative Federation's online transaction services for weeks in April, an attack that the prosecution believes was masterminded by North Korean hackers.

   pbr@yna.co.kr
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