You can view the documentation below, or browse our GitHub Repository, where you can contribute to user manual and FAQ.
The following is an overview of the tools, libraries, and steps needed to build ClamAV.
gmakeon UNIX systems)
checkunit testing framework
Required libraries (including development sources (i.e.
Recommended libraries (including development sources (i.e.
Optional libraries (including development sources (i.e.
ClamAV may execute Bytecode signatures using:
ClamAV’s built-in version of LLVM 2.8
*The performance difference between using LLVM and using the interpeter is negligible. If you prefer to use LLVM / JIT for bytecode signature execution, be advised that we presently only support up to LLVM version 3.6.
The following are thus optional, but required to use LLVM in place of the bytecode interpeter:
The following are optional, but needed for the LLVM JIT unit tests:
Certain versions on certain OSes will cause failures loading virus database:
To install ClamAV locally on an unprivileged shell account you need not create any additional users or groups. Assuming your home directory is
/home/gary you should build it as follows:
./configure --prefix=/home/gary/clamav --disable-clamav make; make install
--disable-clamav switch disables the check for existence of the
clamav user and group but
clamscan would still require an unprivileged account to work in a superuser mode.
If installing to the system, it is recommended to set up at least one special user account to run
clamd. You may choose to set up two separate accounts, one for each. You only need to create these accounts the first time you install ClamAV.
These are instructions specific to some popular operating systems:
If your operating system isn’t specified above, and your OS does not have the
useradd utilities, consult a system manual. Don’t forget to lock access to the account!
Once you have created the clamav user and group, please extract the archive:
tar xzf clamav-[ver].tar.gz cd clamav-[ver]
Assuming you want to install the configuration files in
/etc, configure and build the software as follows:
./configure --sysconfdir=/etc make su -c "make install"
In the last step, the software is installed into the
/usr/local directory and the config files into
/etc. WARNING: Never enable the SUID or SGID bits for Clam AntiVirus binaries.
First, create a database directory. This would be located under the install path
share/clamav. For example:
You will need to create
clamd.conf files in the config directory. In the above example, we chose
/etc, so run the following.
sudo cp /etc/freshclam.conf.sample /etc/freshclam.conf sudo cp /etc/clamd.conf.sample /etc/clamd.conf
At a minimum, you will need to edit each file and remove or comment-out the
Example line. In addition, for
clamd.conf you will need to enable either
For additional recommendations, please read:
To test your local installation execute:
~/clamav/bin/freshclam ~/clamav/bin/clamscan ~
To test your system installation execute:
sudo freshclam sudo clamscan ~
libmilter package and its development files are required. To enable clamav-milter, configure ClamAV with
To configure ClamAV to use a system-installed LLVM library:
./configure --with-system-llvm=/myllvm/bin/llvm-config make sudo make install
The argument to
--with-system-llvm indicates the path name of the LLVM configuration utility (llvm-config). Alternatively, you may use
./configure will search for LLVM in /usr/local/ and then /usr.
Recommended versions of LLVM are 3.2 - 3.6. Some installations have reported problems using earlier LLVM versions. Versions of LLVM beyond 3.6 are not currently supported in ClamAV.
ClamAV includes unit tests that allow you to test that the compiled binaries work correctly on your platform.
The first step is to use your OS’s package manager to install the
check package. If your OS doesn’t have that package, you can download it from SourceForge, build it and install it.
To help clamav’s configure script locate
check, it is recommended that you install
pkg-config, preferably using your OS’s package manager, or from FreeDesktop.org.
The recommended way to run unit-tests is the following, which ensures you will get an error if unit tests cannot be built:
./configure --enable-check make make check
make check is finished, you should get a message similar to this:
================== All 8 tests passed ==================
If a unit test fails, you get a message similar to the following. Note that in older versions of make check may report failures due to the absence of optional packages. Please make sure you have the latest versions of the components noted in section /refsec:components. See the next section on how to report a bug when a unit test fails.
======================================== 1 of 8 tests failed Please report to https://bugzilla.clamav.net/ ========================================
If unit tests are disabled (and you didn’t use -–enable-check), you will get this message:
*** Unit tests disabled in this build *** Use ./configure --enable-check to enable them SKIP: check_clamav PASS: check_clamd.sh PASS: check_freshclam.sh PASS: check_sigtool.sh PASS: check_clamscan.sh ====================== All 4 tests passed (1 tests were not run) ======================
./configure --enable-check should tell you why.
make check reports failed tests, we encourage you to report a bug on bugzilla.
When writing a bug report regarding failed unit tests, please provide the following:
/tmp/clamd-test.logif it exists
pkg-config check --cflags --libs
valgrindis available on your platform, the output of the following:
make check CK_FORK=no ./libtool --mode=execute valgrind unit_tests/check_clamav
Before you can run
clamscan, you must have ClamAV Virus Database (.cvd) file(s) installed in the appropriate location on your system. The default location for these database files are
Here is a listing of currently available ClamAV Virus Database Files:
These files should be downloaded using the
freshclam utility on a periodic basis. While using HTTPS to directly download the CVDs is possible, using
freshclam is the preferred method of keeping the ClamAV virus database files up to date.
freshclam can download database difference files (
.cdiff) to get the latest signature definitions without downloading whole CVD files. This saves a considerable amount of bandwidth.
Please see the freshclam usage section for additional details on freshclam).
As an alternative to building and installing from source, most Linux package managers provide pre-compiled ClamAV packages.
For more information about installing ClamAV via a Package Manager, please visit the “other versions” section on the ClamAV.net Downloads page.