How to communicate to server that a file was infected and blocked by external tool (firewall/antimalware)?

[sickwolf]

I wanted to see what the end user would experience if a malware was detected on Nextcloud, so I uploaded an EICAR test file.

My Nextcloud provider use a firewall that blocked the upload, and returned a 503 error. Nextcloud then alerted me with “Error during upload, status code 503”, which is not user-friendly at all. At first, I thought my provider had some server issues.

The request in question returned a webpage that the end-user obviously cannot see:

Is there a way to tell NC that the uploaded file was blocked by something else ? Or change the notification to something more verbose like "Error during upload, status code 503. A malware might have been detected and blocked during your upload. Contact your administrator for more information. "

I’m thinking that there must be something the error page can return to NC to warn NC about this, either with a json or a special header in the response.

Surely my provider is not the only one using a third-party/external firewall/antimalware protection on their servers.

Thanks to anyone who can provide some insights on this.

[Mornsgrans]

The webserver of your Nextcloud instance resp. Nextcloud itself has no access to the firewall log of your provider. So you cannot get the reason of the block.

[sickwolf]

I understand that, but is there anything the provider can do to notify nextcloud of the block and make the user experience better ? Because a simple 503 error doesn’t say much to any regular user.

EDIT: As said earlier, I cannot imagine that a very not user-friendly error 503 pops up on all instances across the globe when a firewall detect and block a threat, which is a common thing. Surely there is a way to notify the end-user.