What Is Rkhunter?
Rkhunter (Rootkit Hunter) is an open source Unix/Linux based scanner tool for Linux systems released under GPL that scans backdoors, rootkits and local exploits on your systems. It scans hidden 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 into putty
# cd /tmp # wget http://rackmountain.com/scripts/rkhunter-1.4.2.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 id. 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 “email@example.com” with your “Email Id“.
#!/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)' firstname.lastname@example.org
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 information and options please run the following command.
# rkhunter --help