South Korea has become a main target of various types of ransomware attacks but it is struggling to find effective countermeasures, industry officials here said Wednesday.

Local computer users are increasingly susceptible to such malware, some even using the Korean language.

The Korean-language cryptXXX file, which seeks bitcoin, was reported last week and is a more sophisticated scam than the Korean versions of CryptoLocker and Radamant ransomware that infected a number of PCs in 2015.

Ransomware, if installed, restricts access to computer systems and demands a computer user pay a ransom in return for removing it.

That's why ransomware is often called a "cyber hostage-taker."

"It's believed that ransomeware attackers, operating across the world, have begun to recognize South Korea as a target," Choi Sang-myong, a senior official at Hauri Inc., said. "Chances are high that Korean versions of ransomware will further spread."

According to another local cybersecurity firm, Symantec Corp., the number of ransomware cases reported in South Korea last year reached 4,400.

FireEye Inc. also said that ransomware attacks on South Korean firms jumped around 22 times in March from October last year.

The sharp increase is apparently attributed to the spread of bitcoin use in cyberspace. Born in 2009, transactions using bitcoin is hard to trace.

The problem is that there is no solution yet to the elaborate and sophisticated ransomware assaults.

Cybersecurity companies point out that it's best to prevent the infection of ransomware.

"The best way is to back up data frequently," an industry official said, advising computer users not to open suspicious files. (Yonhap)