Tokyo, Dec 26 (IANS): Japan Airlines (JAL) said Thursday that its network system has been restored after a cyberattack earlier in the day disrupted luggage services and delayed some flights.

JAL said ticket sales for both domestic and international flights have now been resumed after a temporary halt, adding that no personal information was leaked and no damage was caused by computer viruses.

The network disruption occurred at 7:24 a.m. local time, causing problems with baggage check-ins and delays for a dozen flights at several Japanese airports, the airline said.

At 8:56 a.m. local time, JAL blocked the data transmission device that was causing the system failure, Xinhua news agency reported.

JAL told police that it may have been the victim of a distributed denial-of-service, or DDoS attack, in which networks are overwhelmed by massive amounts of data from multiple sources over a short period, according to investigative sources.

The company said it was working to counteract the cyberattack and determine its source.

Earlier in the day, passengers at Tokyo's Haneda airport were seen checking their phones and speaking with staff, while there was no significant confusion at Narita airport in Chiba Prefecture. A man in his 30s, travelling from Haneda to Ishigaki Island in Okinawa, expressed concern, saying, "I was able to check in fine, but it's worrying that there's trouble."

Meanwhile, a man in his 60s, headed to Matsuyama in Ehime Prefecture, commented, "It's a nuisance during the busy year-end period."

Meanwhile, cyberattack occurs when there is an unauthorised action against computer infrastructure that compromises the confidentiality, integrity, or availability of its content.

The rising dependence on increasingly complex and interconnected computer systems in most domains of life is the main factor that causes vulnerability to cyberattacks, since virtually all computer systems have bugs that can be exploited by attackers.

Although it is impossible or impractical to create a perfectly secure system, there are many defence mechanisms that can make a system more difficult to attack, making information security a field of rapidly increasing importance in the world today.