President Obama’s recent decision to name a national cybersecurity chief seems auspicious in light of this: A widespread and unusually resilient computer attack that began July 4 knocked out the Web sites of several government agencies, including some that are responsible for fighting cyber crime. Suspected cyber assaults also paralyzed Web sites of major South Korean government agencies, banks and Internet sites in a barrage that appeared linked to the attacks in the U.S., South Korean officials said Wednesday. The Treasury Department, Secret Service, Federal Trade Commission and Transportation Department Web sites were all down at varying points over the holiday weekend and into this week, according to officials inside and outside the government. As we saw in the Russia-Georgia conflict, cyberspace is becoming the new global battlefield: According to Internet technical experts, it was the first time a cyberattack had coincided with a real war. But it will likely not be the last, said Bill Woodcock, the research director of Packet Clearing House, a nonprofit organization that tracks Internet traffic. He said cyberattacks are so inexpensive and easy to mount, with few fingerprints, that they will almost certainly remain a feature of modern warfare. As far as the July 4th attack, North Korea appears to be the main suspect: South Korean intelligence officials believe North Korea or pro-Pyongyang forces in South Korea committed cyber attacks that paralyzed major South Korean and U.S. Web sites, a lawmaker’s aide said Wednesday. On Wednesday, the National Intelligence Service told a group of South Korean lawmakers it believes that North Korea or North Korean sympathizers in the South “were behind” the attacks, according to an aide to one of the lawmakers briefed on the information.