Although it's true you may not know what the file names are until MIME::Parser is done, you do have the option of specifying where to store the attachments beforehand: 
use strict;
use warnings;
use MIME::Parser;

  my $dir = "./mimemail";
  my $parser = new MIME::Parser;
  $parser->output_dir($dir);
  my $entity = $parser->read(\*STDIN) || die "couldn't parse MIME stre
+am";

[download]
You should have enough information at this point to change permissions on the directory or the files within it. Then again, maybe I misunderstand your question. The suggestion by davis should work in any case.

--Jim

In reply to MIME::Parser and specifying directories for saving attachments by jlongino
in thread MIME:Parser vs. file permissions by graff

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