Despite widespread threats of cyber terrorism and virus attacks, 11 September passed almost without incident in the wired world.

Antivirus firms had warned of two Windows-based worms, Chet and Nedal, which were released into the wild specifically to take effect yesterday, but both failed to make an impact.

The Chet worm, which attempted to spread as an email attachment under the name september11.exe, failed spectacularly because it was so full of bugs that it was not considered to pose any sort of threat.

"This seems to be a poor attempt from a wannabe virus writer to exploit the commemoration of 11 September," said Mikko Hypponen, manager of security firm F-Secure. "However, as the worm seems to crash regularly, it won't go far."

Nedal was better constructed and spread over IRC as well as email. This one was considered more dangerous because it is capable of destroying executable files but, again, antivirus firms reported few infections.

Steven Sundermeier, of Central Command, said: "This 11 September worm takes a little more of an aggressive approach than Chet and contains a malicious payload, but we have only received one report at this time."

Security intelligence analyst mi2g speculated that digital attacks from Iraq were likely because a pro-Islamic hacking group, the Unix Security Guards, broke into three machines hosted by AOL Time Warner on 8 September and kept them down until 11 September.

DK Matai, chief executive at mi2g, said: "This is just the first sign of digital attack and protest. As the imminent US/UK action on Iraq gains momentum we are expecting more attacks of a similar nature."

But nothing else happened, according to defacement archive Zone-H, which reported only a few dozen sites defaced with practically no references to 11 September.

Even self-proclaimed uber hacker Kim 'Kimble' Schmitz tried to promote his anti-terrorist hacking unit, Young Intelligent Hackers Against Terror, once again.

A year ago Schmitz claimed that his team of 'elite' crackers had gained access to Osama bin Laden's finances.

On Wednesday he claimed that his group is still very much active and hacking a number of banks, chat servers and email servers in the fight against terrorism.

He even claimed that eight terrorists had been arrested as a direct result of his investigations.