How to Install and Use Linux Malware Detect (LMD) with ClamAV as Antivirus EngineMalware
, or malicious
software, is the designation given to any program that aims at
disrupting the normal operation of a computing system. Although the most
well known forms of malware are viruses, spyware, and adware, the harm
that they intend to cause may range from stealing private information to
deleting personal data, and everything in between, while another
classic use of malware is to control the system in order to use it to
launch botnets in a (D)DoS attack.
other words, you can’t afford to think, “I don’t need to secure my
system(s) against malware since I’m not storing any sensitive or
important data”, because those are not the only targets of malware.
For that reason, in this article we will explain how to install and configure Linux Malware Detect
for short) along with ClamAV
(Antivirus Engine) in RHEL 7.0/6.x
(where x is the version number), CentOS 7.0/6.x
and Fedora 21-12
malware scanner released under the GPL v2 license, specially designed
for hosting environments. However, you will quickly realize that you
will benefit from MalDet
no matter what kind of environment you’re working on.
Installing LMD on RHEL/CentOS 7.0/6.x and Fedora 21-12LMD
is not available from online repositories, but is distributed as a
tarball from the project’s web site. The tarball containing the source
code of the latest version is always available at the following link,
where it can be downloaded with:
# wget http://www.rfxn.com/downloads/maldetect-current.tar.gz
Then we need to unpack the tarball and enter the directory where its contents were extracted. Since current version is 1.4.2
, the directory is maldetect-1.4.2
. There we will find the installation script, install.sh
# tar -xvf maldetect-current.tar.gz
# ls -l | grep maldetect
lines long (including comments), we will see that it not only installs
the tool, but also performs a pre-check to see if the default
installation directory (/usr/local/maldetect
) exists. If not, the script creates the installation directory before proceeding.
Finally, after the installation is completed, a daily execution via cron
is scheduled by placing the cron.daily
script (refer to the image above) in /etc/cron.daily
This helper script will, among other things, clear old temporary data,
check for new LMD releases, and scan the default Apache and web control
panels (i.e., CPanel, DirectAdmin, to name a few) default data
That being said, run the installation script as usual:
Configuring Linux Malware DetectThe configuration of LMD is handled through /usr/local/maldetect/conf.maldet
and all options are well commented to make configuration a rather easy task. In case you get stuck, you can also refer to /usr/local/src/maldetect-1.4.2/README
for further instructions.
In the configuration file you will find the following sections, enclosed inside square brackets:
- EMAIL ALERTS
- QUARANTINE OPTIONS
- SCAN OPTIONS
- STATISTICAL ANALYSIS
- MONITORING OPTIONS
Each of these sections contains several variables that indicate how LMD
will behave and what features are available.
- Set email_alert=1
if you want to receive email notifications of malware inspection
results. For the sake of brevity, we will only relay mail to local
system users, but you can explore other options such as sending mail
alerts to the outside as well.
- Set email_subj=”Your subject here” and [email protected] if you have previously set email_alert=1.
- With quar_hits,
the default quarantine action for malware hits (0 = alert only, 1 =
move to quarantine & alert) you will tell LMD what to do when
malware is detected.
- quar_clean will let you
decide whether you want to clean string-based malware injections. Keep
in mind that a string signature is, by definition, “a contiguous byte
sequence that potentially can match many variants of a malware family”.
the default suspend action for users with hits, will allow you to
disable an account whose owned files have been identified as hits.
- clamav_scan=1 will tell LMD to attempt to detect the presence of ClamAV binary and use as default scanner engine. This yields an up to four times faster scan performance and superior hex analysis. This option only uses ClamAV as the scanner engine, and LMD signatures are still the basis for detecting threats.
: Please note that quar_clean
require that quar_hits
be enabled (=1).
Summing up, the lines with these variables should look as follows in /usr/local/maldetect/conf.maldet
email_subj="Malware alerts for $HOSTNAME - $(date +%Y-%m-%d)"
To install ClamAV
in order to take advantage of the clamav_scan
setting, follow these steps:
Create the repo file /etc/yum.repos.d/dag.repo
name=Dag RPM Repository for Red Hat Enterprise Linux
# yum update && yum install clamdNote
That these are only the basic instructions to install ClamAV in order
to integrate it with LMD. We will not go into detail as far as ClamAV
settings are concerned since as we said earlier, LMD signatures are
still the basis for detecting and cleaning threats.
Testing Linux Malware Detect
Now it’s time to test our recent LMD
installation. Instead of using real malware, we will use the EICAR test files
, which are available for download from the EICAR web site.
# cd /var/www/html
# wget http://www.eicar.org/download/eicar.com
# wget http://www.eicar.org/download/eicar.com.txt
# wget http://www.eicar.org/download/eicar_com.zip
# wget http://www.eicar.org/download/eicarcom2.zip
At this point you can either wait for the next cron
job to run, or execute maldet
manually yourself. We’ll go with the second option:
# maldet --scan-all /var/www/LMD
also accepts wildcards, so if you want to scan only a certain type of file, (i.e. zip files, for example), you can do so:
# maldet --scan-all /var/www/*.zip
# maldet --report REPORT-NUMBER
REPORT-NUMBER is the SCANID
(the SCANID will be slightly different in your case).Important
: Please note that LMD found 5 hits since the eicar.com file was downloaded twice (thus resulting in eicar.com and eicar.com.1).
If you check the quarantine folder (I just left one of the files and deleted the rest), we will see the following:
# ls -l
You can then remove all quarantined files with:
# rm -rf /usr/local/maldetect/quarantine/*
In case that,
# maldet --clean SCANID
get the job done for some reason. You may refer to the following screen
cast for a step-by-step explanation of the above process:
How to Scan and Quarantine Malware in Linux Using LMD (MalDet)
needs to be integrated with cron
, you need to set the following variables in root’s crontab (type crontab -e
as root and hit the Enter
key) in case that you notice that LMD is not running correctly on a daily basis:
This will help provide the necessary debugging information.
In this article we have discussed how to install and configure Linux Malware Detect
, along with ClamAV
, a powerful ally. With the help of these 2 tools, detecting malware should be a rather easy task.
However, do yourself a favor and become familiar with the README
file as explained earlier, and you’ll be able to rest assured that your system is being well accounted for and well managed.
Do not hesitate to leave your comments or questions, if any, using the form below.
Reference LinksLMD Homepage