The IT industry is on stand-by today as the Klez-E worm is expected to deliver its payload.
According to antivirus company Central Command the virus, said to be one of the most common internet worms around, will attempt to overwrite files that have the extensions .bak, .c, .cpp, .doc, .htm, .html, .jpg, .mp3, .mpeg, .mpg, .pas, .txt, .wab and .xls.
Steven Sundermeier, product manager at Central Command, explained that there had been a large number of confirmed infections in the last 30 days and that many more must have gone undetected.
"This poses a serious problem for all internet and email users since today Klez-E unleashes its vastly damaging payload," he said.
First released in November 2001 Klez-E has been detected in 97 countries. It deletes files on local and network drives and overwrites files with random data making them impossible to restore.
A full technical description can be read here.