Hackers in the Czech Republic gained access to a webcam that streamed pictures of a local beauty spot and inserted pictures of the area being "nuked". The video was then broadcast live on television.
The incident occurred on Sunday morning on Czech TV programme Panorama. Hackers interrupted the regular webcam transmission with video "footage" of a nuclear explosion. The gang gained access to a system operated by a sub-contractor.
The stunt was pulled by a group of "artists" known as Ztohoven. Their website went offline as massive numbers of users access the site.
Viewers phoned into the station after seeing a white flash then a huge mushroom cloud in the distance.
The group released a statement on their MySpace page to tell people they were not terrorists or a political group and their goal was not "somehow to frighten the society, or to manipulate it, as we see it everyday in real world and in media [sic]."
"We think that a slight violation of this system, could work as a way to shaken men, whose mental independence should never be affected in democratic lands," the statement read.
Security experts said that this type of hacking demonstrates the high levels of security risk involved when transmitting information across the internet.
"Internet-delivered broadcasts and internet TV transmissions are still in their infancy, but this doesn't stop hackers from attacking weak points in the transmission infrastructure," said Geoff Sweeney, chief technology officer of behavioural analysis software company Tier-3.
"This is relatively new territory, both for the broadcasters and the hackers but the principles of good security practice still apply," he said. "Broadcasters need to look very carefully at their IT security systems to protect their system against these sorts of attacks which can only impact their transmissions and damage their reputations."
Here is the video.
