Action on a vulnerabilty found in a SMTP flow

[Cedricd]

Hello,

How to configure the PA firewall to return a SMTP 541 when vulnerability is seen in a SMTP flow ? I have managed to do it with the AV protection but not with the vulnerability protection.

Cedric

[kiwi · Accepted solution]

Hi @Cedricd,

This should help you out :

https://live.paloaltonetworks.com/t5/Featured-Articles/Tips-amp-Tricks-Complete-Action-List-in-Profi...

Cheers !

-Kim.

[Cedricd]

Thanks @kiwi

From what I see, starting from 7.0, I will be able to use 'reset both' for vulnerabilty and if it is SMTP, it will send a SMTP 541 ?

Currently, I am using 6.1 and it is only working like that for AV protection.

[kiwi]

Hi @Cedricd,

Yes, that is correct.

Cheers !

-Kim.

[aroos_dts]

Hi kiwi,

is it possible that this does not work if there is a vulnerability found inside an attachment?

For example I have emails arriving with office documents where a threat (Microsoft Office Memory Corruption Vulnerability (id 38859)) is found inside the office document and the corresponding email gateway does not receive a smtp error 541 but gets the connection cancelled via tcp reset and retries and retries to deliver the email to the backend server. The email gateway itself states smtp error 442 Bad Connection.

We are on PAN-OS 7.1 so according to the https://live.paloaltonetworks.com/t5/Featured-Articles/Tips-amp-Tricks-Complete-Action-List-in-Profi... the firewall should send smtp error 541

Best regards

Alex

[Cedricd]

That's exactly my problem with PAN-OS 6.1. I was hoping 7.1 solved that issue but it looks like it is not the case ?

[kiwi · Accepted solution]

Hi @aroos_dts , @Cedricd,

I might have mixed up virus/vulnerability in my previous comment :/

It actually depends if the email is identified as virus or as vulnerability.

Note that in Antivirus profile you have an SMTP decoder (you don't have this decoder in Vulnerability profiles).  

The article posted earlier does mention that it only applies to the SMTP decoder.

With the correct action of "reset-both" in the SMTP decoder you will get the 541 response.

However, in the vulnerability profile, there is no such thing as an SMTP decoder so you will get a TCP reset.

The good news is that there is already a feature request to add this functionality to Vulnerability profiles (FR #6548).   You can reach out to your local SE and ask him to add your vote to this feature.

Kind regards,

-Kim.

[aroos_dts]

Hi @kiwi,

thanks for your fast response! So we hope that this will be implemented some day :)

Best regards

Alex