One of the fastest spreading computer viruses is attacking Irish businesses and home computer users resulting in thousands of unwanted e-mails being sent over the internet.
The SOBIG F virus has hit millions of users around the world and is thought by experts to have been spread by spammers trying to find corporate networks that are vulnerable to their mass e-mail advertising campaigns.
Irish internet security firm Entropy has described SOBIG as a growing threat, particularly as computer users will receive infected e-mails from names they would usually trust.
Entropy's John Ryan says the 'F' version is more effective and dangerous than previous versions of SOBIG.
Once users open an e-mail attachment infected with the virus it plunders their address book for new victims, and tries to implant a background programme turning infected machines into a relay for messages sent by the virus's creator.
The outbreak of SOBIG follows the recent attack by the Blaster virus, which specifically targeted computers with Microsoft operating systems.
