Taking Scott's thought a little further... here are a couple of ideas on how to proceed, with some scripting - and the usual qualification that none of this would be a supported mod.
One possibility would be to use the 'remote reference' capability to run a Perl script (using 'pdm_perl' which is supplied with Service Desk Manager), passing the ticket id. The Perl script would locate and read the attachment file using 'pdm_extract', parse out the CC string, then push that into a field in the ticket. Perl can access the output of a 'pdm_extract' command by opening the command with a 'pipe' character appended, as a file handle; and you can build a 'pdm_load' command in Perl to update the ticket with the CC string (for example) and run it as a command line from Perl. The 'remote reference' would be launched by the 'Initial' Activity Notification.
If you want a more integrated solution and are up for a bit more research, you could use the capability to run Perl directly from Spel - documented by Gutis in this post: SPEL How to Execute Remote Reference via Perl code . I haven't tried this facility yet but it opens up some very interesting possibilities.
Hope that helps...
James