[Mimedefang] patch to add blocking of encrypted email via uv scan

[Michael Sofka]

> Luke, have you tried opening the file to see if it requires a password to
> open?  If not, it probably isn't really encrypted.  If so, I have no idea
> how clam was able to spot the encrypted content.

If the same password, or a small set of passwords are used with the
virus, then the resulting encrypted file is constant (or a small set
of constant files), and so the virus scanner will still have patterns
to search for.  Or, it could decrypt the file and search for a single
pattern, presumably whichever is more efficient.

Mike
-- 
Michael D. Sofka              sofkam at rpi.edu
C&CT Sr. Systems Programmer    Email, TeX, epistemology.
Rensselaer Polytechnic Institute, Troy, NY.  http://www.rpi.edu/~sofkam/