
Securing a publicly exposed mailserver with crowdsec
I have been doing this for some time but this weekend i decided to add more relevant logs to block more logs from my Xeams mail gateway appliance.
My log list now contains
authTerminate— bad AUTH attemptshelloTerminate— bad EHLO/HELOinvalidRecipients— directory harvestingrcptTerminate— invalid RCPTtimeoutTerminate— connection timeoutsGreyListing— persistent greylisted sendersForgedSenders— forged sender addresses
This feels almost like a honeypot due to the number of "attacks" - just during this afternoon 105 decisions was made to block traffic, to my mail server alone ✌️
All decisions are fed into a blocklist that my TWO Juniper vSRX firewalls subscribe to and is part of global deny rules in the firewall.
It does not matter if a IP tried to perform a wordpress attach or connect over SMTP - you shall not pass.... ❤️🔥
This might end up on Github soon..