Support Forum
The Forums are a place to find answers on a range of Fortinet products from peers and product experts.
Not applicable

relation between oversized file and AV

Hi all, I' m confused with oversized file " " pass" and " block" , and anti virus function, if the action is Pass, then does AV check less than threshold amount or greater amount? or i' m wrong and something else would happen, it makes me nervous, Best, Kamyar
14 REPLIES 14
RickP

Thus it' s scanning the first 10meg and then passes the rest.
It' s buffering the first 10 MB, but are you certain it' s also scanning it?
Secure_IT_BE_Nick

Can' t find a source at the moment, but it was covered during my FCNSP training also.

[link]https://www.secure-it.be[/link]

[link]https://www.secure-it.be[/link]
MisterAG
New Contributor

Per a ticket that I opened up a few weeks ago, oversized files are indeed scanned inline after they are initially forwarded. We now buffer the first MB, they get forwarded to the host at LAN speeds, then the rest of the file comes in at Internet speed. I was surprised to see that the oversized files were scanned inline, but until I can find a source that says otherwise, I will believe the support rep.
emnoc
Esteemed Contributor III

The person who said it buffers the file and then if it reaches the max size the file is pass or blocked based on the setting, is right. Since the Fortinet AV scanner has no ideal of the size of the file, it has to capture it ( the buffering patr ). So it' s not scanning the file up the max size but buffering it , so it can conduct the AV scanning. We discussed this in my fortinet security class awhile back and that' s how I recalled it. Also you have to protect yourself from exhausting memory , while doing these scans.

PCNSE 

NSE 

StrongSwan  

PCNSE NSE StrongSwan
Eastwind
New Contributor

ORIGINAL: emnoc The person who said it buffers the file and then if it reaches the max size the file is pass or blocked based on the setting, is right. Since the Fortinet AV scanner has no ideal of the size of the file, it has to capture it ( the buffering patr ). So it' s not scanning the file up the max size but buffering it , so it can conduct the AV scanning. We discussed this in my fortinet security class awhile back and that' s how I recalled it. Also you have to protect yourself from exhausting memory , while doing these scans.
So are u saying the Fortinet will buffer the file first then scan whatever buffered next. So is it possible the embedded virus or trojan is located outside the 12MB then what happened?
Announcements

Select Forum Responses to become Knowledge Articles!

Select the “Nominate to Knowledge Base” button to recommend a forum post to become a knowledge article.

Labels
Top Kudoed Authors