Fedora 36 : Rootkit Hunter tool.

rkhunter (Rootkit Hunter) is a Unix-based tool that scans for rootkits, backdoors and possible local exploits. It does this by comparing SHA-1 hashes of important files with known good ones in online databases, searching for default directories (of rootkits), wrong permissions, hidden files, suspicious strings in kernel modules, and special tests for Linux and FreeBSD..., see wikipedia .

You can find it on this website.

On Fedora 36 you can search and install with the DNF tool.

[root@fedora mythcat]# dnf search rkhunter
Last metadata expiration check: 3:38:34 ago on Sat 06 Aug 2022 10:35:34 AM EEST.
======================== Name Exactly Matched: rkhunter ========================
rkhunter.noarch : A host-based tool to scan for rootkits, backdoors and local exploits
[root@fedora mythcat]# dnf install rkhunter.noarch
Last metadata expiration check: 3:39:00 ago on Sat 06 Aug 2022 10:35:34 AM EEST.

The first step is to upgrade it and then you can check the system.

[root@fedora mythcat]# rkhunter --propupd
[ Rootkit Hunter version 1.4.6 ]
File created: searched for 179 files, found 139

[root@fedora mythcat]# rkhunter --check
[ Rootkit Hunter version 1.4.6 ]

Checking system commands...

  Performing 'strings' command checks

...

The result can be found on the log file and you can set settings on the conf file type.

[root@fedora mythcat]# vi /var/log/rkhunter/rkhunter.log
[root@fedora mythcat]# vi /etc/rkhunter.conf

Linux: tools to scan a Linux server for malware and rootkits.

This tools are: chkrootkit, rkhunter, fuser and ISPProtect. All of this tools can be install under Fedora 25 with dnf tool. First tool is chkrootkit is a classic rootkit scanner. It checks your server for suspicious rootkit processes and checks for a list of known rootkit files.

[root@localhost mythcat]# chkrootkit
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
...

The Rootkit Hunter named rkhunter is a Unix-based tool that scans for rootkits, backdoors and possible local exploits.

[root@localhost mythcat]# rkhunter --update
[ Rootkit Hunter version 1.4.2 ]

Checking rkhunter data files...
  Checking file mirrors.dat                                  [ No update ]
  Checking file programs_bad.dat                             [ No update ]
  Checking file backdoorports.dat                            [ No update ]
  Checking file suspscan.dat                                 [ No update ]
  Checking file i18n/cn                                      [ No update ]
  Checking file i18n/de                                      [ No update ]
  Checking file i18n/en                                      [ No update ]
  Checking file i18n/tr                                      [ No update ]
  Checking file i18n/tr.utf8                                 [ No update ]
  Checking file i18n/zh                                      [ No update ]
  Checking file i18n/zh.utf8                                 [ No update ]
[root@localhost mythcat]# rkhunter --propupd
[ Rootkit Hunter version 1.4.2 ]
File created: searched for 172 files, found 136
[root@localhost mythcat]# rkhunter -c --enable all --disable none
[ Rootkit Hunter version 1.4.2 ]

Checking system commands...

  Performing 'strings' command checks
    Checking 'strings' command                               [ OK ]

  Performing 'shared libraries' checks
    Checking for preloading variables                        [ None found ]
    Checking for preloaded libraries                         [ None found ]
    Checking LD_LIBRARY_PATH variable                        [ Not found ]

  Performing file properties checks
    Checking for prerequisites                               [ OK ]
    /usr/bin/awk                                             [ OK ]
    /usr/bin/basename                                        [ OK ]
    /usr/bin/bash                                            [ OK ]
    /usr/bin/cat                                             [ OK ]
    /usr/bin/chattr                                          [ OK ]
    /usr/bin/chmod                                           [ OK ]
    /usr/bin/chown                                           [ OK ]
    /usr/bin/cp                                              [ OK ]
...

Another tool is fuser

[root@localhost mythcat]# fuser -vn tcp 5222
...

The output of this command let you to see the recall of anything on your machine that should be listening on tcp port 5222.

[root@localhost mythcat]# fuser -vn tcp 19635
...

This output indicates that there is a process named "foo" running with PID number and listening on port 19635. The last tool is ISPProtect. ISPProtect is a malware scanner for web servers, it scans for malware in website files and CMS systems like Wordpress, Joomla, Drupal