Sophos has reported this morning that they have received copies of a malicious email that attempts to lure customers into downloading "updates" to their security software. The email looks very authentic, and anyone taken by the scheme ends up with Troj/Spoof-H which in turn allows additional malware to be installed.
The email message is:
“Download latest virus identity (IDE) files
If you are running an older version of Sophos Anti-Virus and do not automatically update your protection, you should download virus identity files (IDEs), which provide detection and disinfection of viruses, worms, Trojans and spyware.
All the IDEs you need are available in a single compressed file. NOTE: Please RUN the application accordingly.”
Additional details in the article