Getting started

YARA is a multi-platform program running on Windows, Linux and Mac OS X. You can find the latest release at https://github.com/VirusTotal/yara/releases.

Compiling and installing YARA

Download the source tarball and get prepared for compiling it:

tar -zxf yara-3.8.1.tar.gz
cd yara-3.8.1
./bootstrap.sh

Make sure you have automake, libtool, make and gcc installed in your system. Ubuntu and Debian users can use:

sudo apt-get install automake libtool make gcc

If you plan to modify YARA’s source code you may also need flex and bison for generating lexers and parsers:

sudo apt-get install flex bison

Compile and install YARA in the standard way:

./configure
make
sudo make install

Run the test cases to make sure that everything is fine:

make check

Some of YARA’s features depend on the OpenSSL library. Those features are enabled only if you have the OpenSSL library installed in your system. If not, YARA is going to work fine but you won’t be able to use the disabled features. The configure script will automatically detect if OpenSSL is installed or not. If you want to enforce the OpenSSL-dependent features you must pass --with-crypto to the configure script. Ubuntu and Debian users can use sudo apt-get install libssl-dev to install the OpenSSL library.

The following modules are not compiled into YARA by default:

  • cuckoo
  • magic
  • dotnet

If you plan to use them you must pass the corresponding --enable-<module name> arguments to the configure script.

For example:

./configure --enable-cuckoo
./configure --enable-magic
./configure --enable-dotnet
./configure --enable-cuckoo --enable-magic --enable-dotnet

Modules usually depend on external libraries, depending on the modules you choose to install you’ll need the following libraries:

  • cuckoo:
    Depends on Jansson for parsing JSON. Some Ubuntu and Debian versions already include a package named libjansson-dev, if sudo apt-get install libjansson-dev doesn’t work for you then get the source code from its repository.
  • magic:
    Depends on libmagic, a library used by the Unix standard program file. Ubuntu, Debian and CentOS include a package libmagic-dev. The source code can be found here.

Installing on Windows

Compiled binaries for Windows in both 32 and 64 bit flavors can be found in the link below. Just download the version you want, unzip the archive, and put the yara.exe and yarac.exe binaries anywhere in your disk.

To install the yara-python extension download and execute the installer corresponding to the version of Python you’re using.

Download Windows binaries

Installing on Mac OS X with Homebrew

To install YARA using Homebrew, simply type brew install yara.

Installing yara-python

If you plan to use YARA from your Python scripts you need to install the yara-python extension. Please refer to https://github.com/VirusTotal/yara-python for instructions on how to install it.

Running YARA for the first time

Now that you have installed YARA you can write a very simple rule and use the command-line tool to scan some file:

echo "rule dummy { condition: true }" > my_first_rule
yara my_first_rule my_first_rule

Don’t get confused by the repeated my_first_rule in the arguments to yara, I’m just passing the same file as both the rules and the file to be scanned. You can pass any file you want to be scanned (second argument).

If everything goes fine you should get the following output:

dummy my_first_rule

Which means that the file my_first_rule is matching the rule named dummy.

If you get an error like this:

yara: error while loading shared libraries: libyara.so.2: cannot open shared
object file: No such file or directory

It means that the loader is not finding the libyara library which is located in /usr/local/lib. In some Linux flavors the loader doesn’t look for libraries in this path by default, we must instruct it to do so by adding /usr/local/lib to the loader configuration file /etc/ld.so.conf:

sudo sh -c 'echo "/usr/local/lib" >> /etc/ld.so.conf'
sudo ldconfig