rkhunter software - Install Linux Rkhunter in RHEL, CentOS and Fedora

rkhunter (Rootkit Hunter) is a open source Unix/Linux based tool released under GPL  that scans for rootkits, backdoors and possible local exploits. rkhunter is a shell script which carries out various checks on the local system to try and detect known rootkits and malware. It also performs checks to see if commands have been modified, if the system startup files have been modified, and various checks on the network interfaces, including checks for listening applications. It scans haddressden files, wrong permissions set on binaries, suspicious strings in kernel etc. To know more about Rkhunter and its features visit http://www.rootkit.nl/.

Installing Rkhunter (Rootkit Hunter) in RHEL, CentOS and Fedora

Step 1: Downloading Rkhunter

Login to your server if you enter via SSH as root and download the latest stable version of Rkhunter tool by going to http://www.rootkit.nl/projects/rootkit_hunter.html or use below Wget command to download it on your systems.

# cd /tmp
# wget http://ncu.dl.sourceforge.net/project/rkhunter/rkhunter/1.4.0/rkhunter-1.4.0.tar.gz

Step 2: Installing Rkhunter

Once you have downloaded the latest version, run the following commands as a root user to install it.

# tar -xvf rkhunter-1.4.0.tar.gz
# cd rkhunter-1.4.0
# ./installer.sh --layout default --install

Step 3: Updating Rkhunter

Run the RKH updater to fill the database properties by running the following command.

# /usr/local/bin/rkhunter --update
# /usr/local/bin/rkhunter --propupd

Step 4: Setting Cronjob and Email Alerts

Create a file called rkhunter.sh under /etc/cron.daily/, which then scans your file system every day and sends email notifications to your email address. Create following file with the help of your favourite editor.

# vi /etc/cron.daily/rkhunter.sh

Add the following lines of code to it and replace “YourServerNameHere” with your “Server Name” and “you@yourdomain.com” with your “Email address“.

#!/bin/sh
(
/usr/local/bin/rkhunter --versioncheck
/usr/local/bin/rkhunter --update
/usr/local/bin/rkhunter --cronjob --report-warnings-only
) | /bin/mail -s 'rkhunter Daily Run (PutYourServerNameHere)' you@yourdomain.com

Set execute permission on the file.

# chmod 755 /etc/cron.daily/rkhunter.sh

Step 5: Manual Scan and Usage

To scan the entire file system, run the Rkhunter as a root user.

# rkhunter --check

The above command generates log file under /var/log/rkhunter.log with the checks results made by Rkhunter. For more help or information please run the following command.

# rkhunter --help