As reported earlier this month by Infosecurity, South Korea's internet was hit by a massive wave of timed hacker attacks that many observers said originated from internet users sympathetic to the cause of North Korea.
The attacks were so ferocious, Infosecurity understands, that several linked US websites were also hit by the attacks, and slowed down as a result.
The Vietnamese CERT operation's director Nguyen Tu Quang told reporters that his operation is only a small centre, but has been successful in finding the origin of attackers.
"And then we get in trouble," he said.
According to Quang, VNCERT has received an "official complaint" from KrCERT about its efforts to track down the source of computer virus attacks on Web sites in South Korea and the US.
Some newswires, meanwhile, say that the hacker attacks earlier this month on sensitive government and business web sites in the US and South Korea caused widespread concern.
The source of the attacks was variously reported to be North Korea, Britain and elsewhere.
"I am very frustrated with this case because I had not expected the way people would respond to our help," Quang told reporters.