This Tuesday, Sophos already indicated that the latest version of the Sober computer worm – Sober.Z in its nomenclature – was the most intercepted virus on the World Wide Web with 61% of reports (see A worm spreads quickly under the pretext of FBI surveillance and After the FBI, the Sober Worm Uses Paris Hilton ).

Since then, it seems that the situation has deteriorated further because Sophos indicates Thursday that the maggot is responsible for 81% of virus interceptions and that no less than one in 17 emails is contaminated by its care, a diffusion qualified as epidemic by the computer security firm.

In its new alert , Sophos urges all internet users to beware of the worm that spreads as an attachment to emails telling recipients they are being watched by the FBI, or offering a supposedly free video of Paris Hilton and Nicole Richie .

As always, statistics vary from one security firm to another. According to figures from F-Secure , the publisher which indicated on Tuesday that the latest Sober was the source of 44% of virus reports, however, there seems to be a stabilization in the spread of Sober.Y, which is now responsible 43% of incidents in the last 24 hours.