A number of websites based in Vietnam were hacked and defaced this week, with the hackers apparently just warning the site owners of their poor security.
The hackers left a note introducing themselves as the Die Group on the front page of the websites, according to SecurityDaily.net, a website run by the Vietnam Information Security Association.
"Fix Your Security NOW! We Will Come Back Soon...," the hackers wrote in the note.
Most of the affected websites are of small companies, and none of them are that of government agencies.
According to SecurityDaily, Die Group seemed to be a new group from Vietnam.
Most of the hacked websites were still inaccessible as of Thursday morning.
SecurityDaily said it will send details of the attack to Vietnam Computer Emergency Response Team at the information ministry, so the team can help the affected sites fix their security flaws.