ABC Mail Manager

I am looking for a mail manager to use on my site. I do not have access to
a db, so I wanted to use one that did not require one. I've installed ABC
Mail Manager on my site and it is set up and ready to use. However, I am
concerned about security. I recall at one time a query to my site looking
for a mail manager, probably from a spammer looking for a way to send spam.
My question is, how secure is this program ? Are there others or other
methods I should consider?