This is a new malicious attack that's not widespread and provides all the more reason to stay up-to-date with Microsoft Security updates.
MS04-023: PGPCoder Trojan - Encrypts & demands $200 for the key
http://news.zdnet.com/2100-1009_22-5718678.html
http://www.websensesecuritylabs.com/alerts/alert.php?AlertID=194
http://secunia.com/virus_information/18207/pgpcoder/
Researchers at Symantec have seen the malicious program used in the ransom attack. The "Trojan.Pgpcoder" searches a victim's hard disk drive for 15 common file types, including images and Microsoft Office file types. It then encrypts the files, removes the originals and drops a note asking $200 for the encryption key, Friedrichs said.
This memory-resident Trojan arrives via Internet or copied from disks. Upon execution, it encrypts all files on the system having the following extensions:
- ASC
- DB
- DB1
- DB2
- DBF
- DOC
- HTM
- HTML
- JPG
- PGP
- RAR
- RTF
- TXT
- XLS
- ZIP