topic Re: Antivirus Profile and Default Actions in General Topics

Antivirus Profile and Default Actions

Luke_R — Wed, 22 Jan 2020 04:46:10 GMT

I've been looking at our PA, and I've found that it's detecting viruses being delivered in SMTP traffic. The PA is alerting, but taking no further action.

Looking at this guide here, I understand that Palo Alto have this set based on the best recommendation at the time.

https://docs.paloaltonetworks.com/pan-os/7-1/pan-os-admin/policy/best-practice-internet-gateway-security-policy/create-best-practice-security-profiles

I'm wondering why we wouldn't want to block viruses on the PA, like we do with http(s) traffic by default?

Is this because we're assuming that there will be some other AV on the mail server?

Or is it because we're not assuming that the PA will not go on the edge of the network?

Thanks!

Re: Antivirus Profile and Default Actions

kiwi — Wed, 22 Jan 2020 09:03:29 GMT

Hi @Luke_R ,

Best practice would be to use the reset-both action to return a 541 response to the sending SMTP server to prevent it from resending the blocked message.

https://docs.paloaltonetworks.com/best-practices/9-1/internet-gateway-best-practices/best-practice-internet-gateway-security-policy/create-best-practice-security-profiles.html

Cheers !

-Kiwi.

Re: Antivirus Profile and Default Actions

Luke_R — Wed, 22 Jan 2020 21:06:30 GMT

Thanks, this makes sense to me. I'm surprised they don't do this out of the box though.