Zimbra uses memcached and if not properly configured could lead to a vulnerable system.
If you want to read more on memcached attack read this:
https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from-port-11211/
How to resolve this vulnerability in 3 steps:
- Enable firewall on your server
- Setup zimbra specific rules
- Bind memcached to localhost
- Deny memcached port from localhost
Let’s start.