How to Install Chkrootkit on Ubuntu 16.04

July 15, 2018 in Tutorial5 minutes

Overview

In this tutorial we’ll learn how to install chkrootkit on Ubuntu 16.04 (Xenial Xerus). Chkrootkit is a tool that will check locally for a sign of a rootkit. It will check the following items:

Modification of system binaries
Check whether network interface is in promiscuous mode or not
Deletion of lastlog, utmp and wtmp
Signs for LKM trojans

Objectives

In this tutorial we’ll learn how to install chkrootkit from Ubuntu repository and also install chkrootkit from source.

Prerequisite

Ubuntu 16.04 installation, you can use any flavor of Ubuntu 16.04 like Kubuntu or Xubuntu. In this tutorial I use Ubuntu Server 16.04. Let’s get started.

Install Chkrootkit on Ubuntu 16.04

Update apt repository metadata:

sudo apt-get update

Install chkrootkit using command below:

sudo apt-get -y install chkrootkit

When we run chkrootkit without root privileges:

chkrootkit

We will get error similar to output below:

/usr/sbin/chkrootkit need root privileges

We can run chkrootkit using sudo:

sudo chkrootkit

Sample of chkrootkit scanning output:

ROOTDIR is `/'

    Checking `amd'... not found
Checking `basename'...                                      not infected
    Checking `biff'... not found
Checking `chfn'...                                          not infected
    Checking `chsh'... not infected
Checking `cron'...                                          not infected
    Checking `crontab'... not infected
Checking `date'...                                          not infected
    Checking `du'... not infected
Checking `dirname'...                                       not infected
    Checking `echo'... not infected
Checking `egrep'...                                         not infected
    Checking `env'... not infected
Checking `find'...                                          not infected
    Checking `fingerd'... not found
Checking `gpm'...                                           not found
    Checking `grep'... not infected
Checking `hdparm'...                                        not infected
    Checking `su'... not infected
Checking `ifconfig'...                                      not infected
    Checking `inetd'... not infected
Checking `inetdconf'...                                     not found
    Checking `identd'... not found
Checking `init'...                                          not infected
    Checking `killall'... not infected
Checking `ldsopreload'...                                   not infected
    Checking `login'... not infected
Checking `ls'...                                            not infected
    Checking `lsof'... not infected
Checking `mail'...                                          not found
    Checking `mingetty'... not found
Checking `netstat'...                                       not infected
    Checking `named'... not found
Checking `passwd'...                                        not infected
    Checking `pidof'... not infected
Checking `pop2'...                                          not found
    Checking `pop3'... not found
Checking `ps'...                                            not infected
    Checking `pstree'... not infected
Checking `rpcinfo'...                                       not found
    Checking `rlogind'... not found
Checking `rshd'...                                          not found
    Checking `slogin'... not infected
Checking `sendmail'...                                      not found
    Checking `sshd'... not infected
Checking `syslogd'...                                       not tested
    Checking `tar'... not infected
Checking `tcpd'...                                          not infected
    Checking `tcpdump'... not infected
Checking `top'...                                           not infected
    Checking `telnetd'... not found
Checking `timed'...                                         not found
    Checking `traceroute'... not found
Checking `vdir'...                                          not infected
    Checking `w'... not infected
Checking `write'...                                         not infected
    Checking `aliens'... no suspect files
Searching for sniffer's logs, it may take a while... nothing found
Searching for rootkit HiDrootkit's default files... nothing found
Searching for rootkit t0rn's default files... nothing found
Searching for t0rn's v8 defaults... nothing found
Searching for rootkit Lion's default files... nothing found
Searching for rootkit RSHA's default files... nothing found
Searching for rootkit RH-Sharpe's default files... nothing found
Searching for Ambient's rootkit (ark) default files and dirs... nothing found
Searching for suspicious files and dirs, it may take a while... The following suspicious files and directories were found:
 /lib/modules/4.4.0-130-generic/vdso/.build-id
/lib/modules/4.4.0-130-generic/vdso/.build-id
Searching for LPD Worm files and dirs... nothing found
Searching for Ramen Worm files and dirs... nothing found
Searching for Maniac files and dirs... nothing found
Searching for RK17 files and dirs... nothing found
Searching for Ducoci rootkit... nothing found
Searching for Adore Worm... nothing found
Searching for ShitC Worm... nothing found
Searching for Omega Worm... nothing found
Searching for Sadmind/IIS Worm... nothing found
Searching for MonKit... nothing found
Searching for Showtee... nothing found
Searching for OpticKit... nothing found
Searching for T.R.K... nothing found
Searching for Mithra... nothing found
Searching for LOC rootkit... nothing found
Searching for Romanian rootkit... nothing found
Searching for Suckit rootkit... nothing found
Searching for Volc rootkit... nothing found
Searching for Gold2 rootkit... nothing found
Searching for TC2 Worm default files and dirs... nothing found
Searching for Anonoying rootkit default files and dirs... nothing found
Searching for ZK rootkit default files and dirs... nothing found
Searching for ShKit rootkit default files and dirs... nothing found
Searching for AjaKit rootkit default files and dirs... nothing found
Searching for zaRwT rootkit default files and dirs... nothing found
Searching for Madalin rootkit default files... nothing found
Searching for Fu rootkit default files... nothing found
Searching for ESRK rootkit default files... nothing found
Searching for rootedoor... nothing found
Searching for ENYELKM rootkit default files... nothing found
Searching for common ssh-scanners default files... nothing found
Searching for Linux/Ebury - Operation Windigo ssh... Possible Linux/Ebury - Operation Windigo installetd
Searching for 64-bit Linux Rootkit ... nothing found
Searching for 64-bit Linux Rootkit modules... nothing found
Searching for suspect PHP files... nothing found
Searching for anomalies in shell history files... nothing found
Checking `asp'...                                           not infected
    Checking `bindshell'... not infected
Checking `lkm'...                                           chkproc: nothing detected
    chkdirs: nothing detected
    Checking `rexedcs'... not found
Checking `sniffer'...                                       lo: not promisc and no packet sniffer sockets
    enp0s3: PACKET SNIFFER(/sbin/dhclient[882])
    Checking `w55808'... not infected
Checking `wted'...                                          chkwtmp: nothing deleted
    Checking `scalper'... not infected
Checking `slapper'...                                       not infected
    Checking `z2'... chklastlog: nothing deleted
Checking `chkutmp'...                                       chkutmp: nothing deleted
    Checking `OSX_RSPLUG'... not infected

Enable Daily Check of chkrootkit

We can enable daily check by changing configuration file. Open /etc/chkrootkit.conf

Find line:

RUN_DAILY="false"

Replace with:

RUN_DAILY="true"

Install Latest Version of Chkrootkit from Source

Chkrootkit shipped with Ubuntu 16.04 (Xenial Xerus) is not the latest version of chkrootkit.

We can check using dpkg with option -l:

dpkg -l | grep chkrootkit
ii chkrootkit 0.50-3.2 amd64 rootkit detector

At the time of this writing, the latest stable version of chkrootkit is version 0.52. We can download latest stable version of chkrootkit from [chkrootkit download page][1].

Before we download and compile chkrootkit let’s install make and gcc:

sudo apt-get install -y make gcc

Download chkrootkit source code:

wget -c ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit-0.52.tar.gz

Extract downloaded archive. This will create new directory named chkrootkit-0.52:

tar xzf chkrootkit-0.52.tar.gz

Go to extracted directory:

cd chkrootkit-0.52/

Compile chkrootkit using command below:

make sense

We can check chkrootkit that we just compiled:

./chkrootkit -V
chkrootkit version 0.52

Summary

In this tutorial we learned how to install chkrootkit on Ubuntu 16.04 (Xenial Xerus). We also learned enabling daily check of chkrootkit.

To get the updated chkrootkit version we learn compiling chkrootkit from source.

Hope this tutorial helps you secure your system from potential rootkit by scanning your systems for known rootkits.

 [1]: http://www.chkrootkit.org/download/