What are some alternatives?
When comparing amavisd-new and CryptoPrevent, you can also consider the following products
MailScanner - MailScanner is a open source email security system design for Linux-based email gateways.
AppCheck Anti-Ransomware - Protect your PC with 100% Signatureless Anti-Ransomware AppCheck
SpamAssassin - Use this program to "Unspam" your mailbox(es).
RansomFree - Protect your PC from ransomware with multiple detection methods.
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
Kaspersky Anti-Ransomware Tool for Business - A free software that offers complementary security to protect corporate users from ransomware.