Virus Scanner Support¶
Overview¶
ClamAV is the only _officially_ supported virus scanner available for use with ownCloud. However, other anti-virus software can be used, so long as they:
- Can receive data streams via pipe on the command-line and return an exit code
- Return a parsable result, on stdout
How ClamAV Works With ownCloud¶
Before you go about installing and configuring it, here is a bit of background which may be handy to know. ownCloud integrates with anti-virus tools by connecting to them via:
- A URL and port
- A socket
- Streaming the data from the command-line via a pipe with a configured executable
Files are checked when they are either uploaded or updated, whether that’s when they’re edited or saved, but not when they are downloaded.
The ownCloud Antivirus extension sends files as streams to a ClamAV service (which can be on the same ownCloud server or on another server within the same network) which in turn scans them and returns a scan result.
ownCloud evaluates either the exit code returned from ClamAV or parses the stdout response to retrieve the result of the scan. Based on ownCloud’s evaluation of the response, an appropriate response is then taken, such as recording a log message, or deleting the file.
Important
File Cache
ownCloud doesn’t support a file cache of previously scanned files.
Configuring the ClamAV Antivirus Scanner¶
You can configure your ownCloud server to automatically run a virus scan on newly-uploaded files using the Antivirus App for Files. The Antivirus App for Files integrates the open source anti-virus engine ClamAV with ownCloud.
ClamAV detects all forms of malware including Trojan horses, viruses, and worms. What’s more, it operates on all the key operating systems, including Windows, Linux, and Mac files, and can scan compressed files, executables, image files, Flash, PDF, as well as many others.
ClamAV’s Freshclam daemon automatically updates its malware signature database at scheduled intervals. ClamAV runs on Linux and any Unix-type operating system, and Microsoft Windows. You must first install ClamAV, and then install and configure the Antivirus App for Files on ownCloud.
Important
Operating System Note
ownCloud has only been tested with ownCloud on Linux, so these instructions are for Linux systems.
Installing ClamAV¶
As always, the various Linux distributions manage installing and configuring ClamAV in different ways.
Debian, Ubuntu, Linux Mint¶
On Debian and Ubuntu systems, and their many variants, install ClamAV with these commands:
apt-get install clamav clamav-daemon
The installer automatically creates default configuration files and launches the
clamd
and freshclam
daemons. You don’t have to do anything more, though
it’s a good idea to review the ClamAV documentation and your settings in
/etc/clamav/
. Enable verbose logging in both clamd.conf
and
freshclam.conf
until you get any kinks worked out.
Red Hat 7, CentOS 7¶
On Red Hat 7 and related systems, you must install the Extra Packages for Enterprise Linux (EPEL) repository, and then install ClamAV:
yum install epel-release
yum install clamav clamav-scanner clamav-scanner-systemd clamav-server
clamav-server-systemd clamav-update
This installs two configuration files: /etc/freshclam.conf
and
/etc/clamd.d/scan.conf
. You must edit both of these before you can run
ClamAV. Both files are well-commented, and man clamd.conf
and man
freshclam.conf
explain all the options. Refer to /etc/passwd
and
/etc/group
when you need to verify the ClamAV user and group.
First, edit /etc/freshclam.conf
and configure your options.
freshclam
updates your malware database, so you want it to run frequently to
get updated malware signatures. Run it manually post-installation to download
your first set of malware signatures:
freshclam
The EPEL packages do not include an init file for freshclam
, so the quick
and easy way to set it up for regular checks is with a cron job. This example
runs it every hour at 47 minutes past the hour:
# m h dom mon dow command
47 * * * * /usr/bin/freshclam --quiet
Please avoid any multiples of 10, because those are when the ClamAV servers are hit the hardest for updates.
Next, edit /etc/clamd.d/scan.conf
. When you’re finished you must enable
the clamd
service file and start clamd
:
systemctl enable clamav-daemon.service
systemctl start clamav-daemon.service
That should take care of everything. Enable verbose logging in scan.conf
and freshclam.conf
until it is running the way you want.
Enabling the Antivirus App for Files¶
To enable the Antivirus App for Files, go to your ownCloud Apps page to enable it.

Configuring ClamAV on ownCloud¶
Next, go to your ownCloud Admin page and set your ownCloud logging level to Everything.

Now, find your Antivirus Configuration panel on your Admin page.

ClamAV runs in one of three modes:
Daemon (Socket)
In this mode, ClamAV runs in the background on the same server as the ownCloud
installation. When there is no activity clamd
places a minimal load on your
system. However, if your users upload large volumes of files, you will see high
CPU usage. So, please keep this in mind.
Daemon Via Host:Port
In this mode, ClamAV runs on a different server. This is a good option for ownCloud servers with high volumes of file uploads.
Executable
In this mode, ClamAV runs on the same server as the ownCloud installation, and
the clamscan
command only runs when a file is uploaded. clamscan
is slow
and not always reliable for on-demand usage; it is better to use one of the
daemon modes.
Daemon (Socket)¶
ownCloud should detect your clamd
socket and fill in the Socket
field. This is the LocalSocket
option in clamd.conf
. You can
run netstat
to verify:
netstat -a|grep clam
unix 2 [ ACC ] STREAM LISTENING 15857 /var/run/clamav/clamd.ctl
.. figure:: ../images/antivirus-daemon-socket.png
The Stream Length
value sets the number of bytes read in one pass.
10485760 bytes, or ten megabytes, is the default. This value should be
no larger than the PHP memory_limit
settings, or physical memory if
memory_limit
is set to -1 (no limit).
Action for infected files found while scanning
gives you the choice of
logging any alerts without deleting the files, or immediately deleting
infected files.
Daemon¶
For the Daemon option, you need the hostname or IP address of the remote server running ClamAV and the server’s port number.
Executable¶
The Executable option requires the path to clamscan
, which is the
interactive ClamAV scanning command. ownCloud should find it automatically.
When you are satisfied with how ClamAV is operating, you might want to go back and change all of your logging to less verbose levels.
Rule Configuration¶
ownCloud provides the ability to customize how ownCloud reacts to the
response provided by an anti-virus scan. To do so, under Admin -> Antivirus
Configuration -> Advanced
, which you can see in the screenshot below, you can
view and change the existing rules. You can also add new ones.
Rules can match on either an exit status (e.g., 0, 1, or 40) or
a pattern in the string returned from ClamAV (e.g., /.*: (.*) FOUND$/
).
Update An Existing Rule¶
To match on an exit status, change the “Match by” dropdown list to “Scanner exit status” and in the “Scanner exit status or signature to search” field, add the status code to match on.
To match on the scanner’s output, change the “Match by” dropdown list to “Scanner output” and in the “Scanner exit status or signature to search” field, add the regular expression to match against the scanner’s output.
Then, while not mandatory, add a description of what the status or scan output means. After that, set what ownCloud should do when the exit status or regular expression you set matches the value returned by ClamAV. To do so change the value of the dropdown in the “Mark as” column.
The dropdown supports the following three options:
Option | Description |
---|---|
Clean | The file is clean, and contains no viruses |
Infected | The file contains a virus |
Unchecked | No action should be taken |
With all these changes made, click the check mark on the left-hand side of the “Match by” column, to confirm the change to the rule.
Add A New Rule¶
To add a new rule, click the button marked “Add a rule” at the bottom left of the rules table. Then follow the process outlined in Update An Existing Rule.
Delete An Existing Rule¶
To delete an existing rule, click the rubbish bin icon on the far right-hand side of the rule that you want to delete.