File filter

The file filter can be applied directly to firewall policies and supports various traffic protocols in proxy or flow mode.

Protocol	Proxy mode	Flow mode
CIFS	Yes	Yes
FTP	Yes	Yes
HTTP	Yes	Yes
IMAP	Yes	Yes
MAPI	Yes	No
POP3	Yes	Yes
SMTP	Yes	Yes
SSH	Yes	No

Prior to FortiOS 6.4.1, file filter was embedded in the web filter, email filter, SSH inspection, and CIFS profiles.

To configure a file filter in the GUI:

1. Configure the filter profile:
   1. Go to Security Profiles > File Filter and click Create New.
   2. Select a Feature set.
   3. In the Rules table, click Create New.
   4. Configure the settings as required.

      

   5. Click OK to save the rule.
   6. Optionally, create more rules.

      

   7. Click OK to save the filter profile.
2. Apply the filter to a policy:
   1. Go to Policy & Objects > Firewall Policy and edit an existing policy or create a new one.
   2. In the Security Profiles section, enable File Filter.
   3. Select the filter from the dropdown box.

      

   4. Configure the other settings as needed.
   5. Click OK.

To configure a file filter in the CLI:

1. Configure the file filter profile:

   config file-filter profile
       edit "test"
           set comment ''
           set feature-set flow
           set replacemsg-group ''
           set log enable
           set scan-archive-contents enable
           config rules
               edit "r2"
                   set comment ''
                   set protocol http ftp smtp imap pop3 cifs
                   set action block
                   set direction outgoing
                   set password-protected any
                   set file-type "sis" "tar" "tiff" "torrent" "upx" "uue" "wav" "wma" "xar" "xz" "zip"
               next
               edit "r1"
                   set comment ''
                   set protocol http ftp smtp imap pop3 cifs
                   set action log-only
                   set direction any
                   set password-protected any
                   set file-type ".net" "7z" "activemime" "arj" "aspack" "avi" "base64" "bat" "binhex" "bmp" "bzip" "bzip2"
               next
               edit "r3"
                   set comment ''
                   set protocol http ftp smtp imap pop3
                   set action block
                   set direction any
                   set password-protected any
                   set file-type "binhex"
               next
           end
       next
   end

2. Apply the filter to a policy:

   config firewall policy
       edit 1
           set name "filefilter-policy"
           set srcintf "port10"
           set dstintf "port9"
           set srcaddr "all"
           set dstaddr "all"
           set srcaddr6 "all"
           set dstaddr6 "all"
           set action accept
           set schedule "always"
           set service "ALL"
           set utm-status enable
           set profile-protocol-options "protocol"
           set ssl-ssh-profile "protocols"
           set file-filter-profile "test"
           set auto-asic-offload disable
           set np-acceleration disable
           set nat enable
       next
   end

Logs

Go to Log & Report > File Filter to view the file filter logs.

Log samples

date=2020-04-21 time=17:04:02 logid="1900064000" type="utm" subtype="file-filter" eventtype="file-filter" level="warning" vd="root" eventtime=1587513843211612684 tz="-0700" policyid=1 sessionid=1751 srcip=10.1.100.22 srcport=57382 srcintf="port21" srcintfrole="undefined" dstip=172.16.200.44 dstport=445 dstintf="port23" dstintfrole="undefined" proto=6 service="CIFS" profile="filefilter" direction="incoming" action="blocked" filtername="1" filename="sample\\putty.exe" filesize=454656 filetype="exe" msg="File was blocked by file filter."

date=2020-04-21 time=17:03:54 logid="1900064000" type="utm" subtype="file-filter" eventtype="file-filter" level="warning" vd="root" eventtime=1587513834376811325 tz="-0700" policyid=1 sessionid=1742 srcip=10.1.100.22 srcport=36754 srcintf="port21" srcintfrole="undefined" dstip=172.16.200.44 dstport=22 dstintf="port23" dstintfrole="undefined" proto=6 service="SSH" subservice="SCP" profile="filefilter" direction="incoming" action="blocked" filtername="1" filename="test.pdf" filesize=571051 filetype="pdf" msg="File was blocked by file filter."

date=2020-04-21 time=17:00:30 logid="1900064000" type="utm" subtype="file-filter" eventtype="file-filter" level="warning" vd="root" eventtime=1587513630482716465 tz="-0700" policyid=1 sessionid=1684 srcip=10.1.100.22 srcport=58524 srcintf="port21" srcintfrole="undefined" dstip=172.16.200.44 dstport=143 dstintf="port23" dstintfrole="undefined" proto=6 service="IMAP" profile="filefilter" direction="incoming" action="blocked" from="pc4user1@qa.fortinet.com" to="pc4user2@qa.fortinet.com" recipient="pc4user2" subject="QA Test" filtername="1" filename="test.JPG" filesize=48079 filetype="jpeg" msg="File was blocked by file filter."

date=2020-04-21 time=16:59:58 logid="1900064000" type="utm" subtype="file-filter" eventtype="file-filter" level="warning" vd="root" eventtime=1587513598866551739 tz="-0700" policyid=1 sessionid=1674 srcip=10.1.100.22 srcport=39854 srcintf="port21" srcintfrole="undefined" dstip=172.16.200.44 dstport=110 dstintf="port23" dstintfrole="undefined" proto=6 service="POP3" profile="filefilter" direction="incoming" action="blocked" from="pc4user1@qa.fortinet.com" to="pc4user2@qa.fortinet.com" recipient="pc4user2" subject="QA Test" filtername="1" filename="test.JPG" filesize=48079 filetype="jpeg" msg="File was blocked by file filter."

date=2020-04-21 time=16:58:31 logid="1900064000" type="utm" subtype="file-filter" eventtype="file-filter" level="warning" vd="root" eventtime=1587513511516745955 tz="-0700" policyid=1 sessionid=1619 srcip=10.1.100.22 srcport=53144 srcintf="port21" srcintfrole="undefined" dstip=172.16.200.44 dstport=25 dstintf="port23" dstintfrole="undefined" proto=6 service="SMTP" profile="filefilter" direction="outgoing" action="blocked" from="pc4user1@qa.fortinet.com" to="pc4user2@qa.fortinet.com" sender="pc4user1@qa.fortinet.com" recipient="pc4user2@qa.fortinet.com" subject="QA Test" filtername="1" filename="test.PNG" filesize=65173 filetype="png" msg="File was blocked by file filter."

date=2020-04-21 time=16:58:14 logid="1900064000" type="utm" subtype="file-filter" eventtype="file-filter" level="warning" vd="root" eventtime=1587513494608988795 tz="-0700" policyid=1 sessionid=1605 srcip=10.1.100.22 srcport=43186 srcintf="port21" srcintfrole="undefined" dstip=172.16.200.44 dstport=21 dstintf="port23" dstintfrole="undefined" proto=6 service="FTP" profile="filefilter" direction="incoming" action="blocked" filtername="1" filename="index.html" filesize=21 filetype="html" msg="File was blocked by file filter."