The nation's first ever criminal case involving a hijacked wireless Internet connection came to light this month, prompting online security experts to warn that home Wi-Fi routers may be open to attack if not properly protected.
Users need to set a password and switch on encryption, or their network can be hacked within minutes by someone close enough to eavesdrop on the wireless signal, such as a user in an adjacent apartment, said Yuichi Nozawa, a consultant with the government-affiliated Information-technology Promotion Agency (IPA), a body that advises on digital security.
Cracking the security itself is relatively simple for one common form of encryption and can be done using free software.