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Administration Guide

File filter

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 > Security Events and select the File Filter card 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."

More Links

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 > Security Events and select the File Filter card 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."