Security software firms are rushing out patches for a new version of the Bagle worm.
Bagle.ay is spreading rapidly over the internet as an attachment. The worm is a Windows executable file with a 19KB payload.
Kaspersky Labs, one of a number of companies distributing a patch for the worm, says Bagle.ay is attached to messages with subject lines such as "Delivery service mail", "Delivery by mail", "Registration is accepted", "Is delivered mail", and "You are made active".
The message itself will read either "Thanks for use of our software" or "Before use read the help". The attachment name is chosen from the following: "wsd01", "viupd02", "siupd02", "guupd02", "zupd02", "upd02", or "Jol03".
The worm is activated when a user opens the attachment. As well as trying to spread to other users over the internet via an infected user’s e-mail address book, the worm attempts to shut down security protection on their PC, opening them up to other malicious attacks.