Here is a sample.  The term "Blocked" is used.  Does ClamAV scan the files looking for viruses or just it just wholescale block them?

Amavisd, using clamAV has a series of decoders.  Hence my question.

### BLOCKED ANYWHERE
# qr'^UNDECIPHERABLE$',  # is or contains any undecipherable components
  qr'^\.(exe-ms|dll)$',                   # banned file(1) types, rudimentary
# qr'^\.(exe|lha|cab|dll)$',              # banned file(1) types

### BLOCK THE FOLLOWING, EXCEPT WITHIN UNIX ARCHIVES:
# [ qr'^\.(gz|bz2)$'             => 0 ],  # allow any in gzip or bzip2
  [ qr'^\.(rpm|cpio|tar)$'       => 0 ],  # allow any in Unix-type archives
This is completely unrelated to ClamAV or virus scanning in general. There is a amavis-users mailing list you might check out.