Here is few interesting things regarding the “ShellShock” Vulnerability extracted …

Thursday, 28th March 2024

Comment on Fixing Shellshock new critical remote bash shell exploitable vulnerability on Debian / Ubuntu / CentOS / RHEL / Fedora / OpenSuSE and Slackware by admin.

Here is few interesting things regarding the “ShellShock” Vulnerability extracted from David A. Wheeler paper:

The probability of vulnerability was somewhat less on Debian and Ubuntu, because their default non-interactive shell is dash (which was not vulnerable) instead of bash, but there were still cases where they could be vulnerable. One point of confusion about Debian and Ubuntu is that their default interactive shell is bash, while their default non-interactive shell is dash, and it is primarily the non-interactive shell (aka /bin/sh) that matters in the shellshock vulnerability. Similarly, Apple MacOS does not use bash in many circumstances, but there were cases where it could be vulnerable. Android systems use Linux but normally use the MirBSD (mksh) shell, which was not vulnerable.

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Install and configure rkhunter for improved security on a PCI DSS Linux / BSD servers with no access to Internet
       –rwo, –report-warnings-only
              This option causes only warning messages to be displayed. This can be useful when rkhunter is run via cron. Other options may
              be used to force other items of information to be displayed.

       –sk, –skip-keypress
              When  the  –check command option is used, after certain sections of tests, the user will be prompted to press the return key
              in order to continue. This option disables that feature, and rkhunter will run until all the tests have completed.

         


Install and configure rkhunter for improved security on a PCI DSS Linux / BSD servers with no access to Internet
As rkhunter check, can be pretty annoying and ask you to press keypresses multiple times and spit you a lot of unnecessery data a very good useful option arguments are:

–rwo and –sk

# rkhunter -c –rwo –sk
Warning: The SSH and rkhunter configuration options should be the same:
         SSH configuration option 'PermitRootLogin': yes
         Rkhunter configuration option 'ALLOW_SSH_ROOT_USER': no


Fix eth changing network interface names from new Linux naming scheme ens, eno, em1 to legacy eth0, eth1, eth2 on CentOS Linux

Sorry for really late reply.

perhaps you have to create it or rename the ifcfg-eno1 to ifcfg-eth1 or you have some old ifcfg-enp1s0f0 or ifcfg-eno still under /etc/sysconfig/network-scripts/ interfering


How to RPM update Hypervisors and Virtual Machines running Haproxy High Availability cluster on KVM, Virtuozzo without a downtime on RHEL / CentOS Linux
if you happen to be missing versionlock plugin and you need to get use of it

yum versionlock capabilities

You will have to install yum-utils package:

For example on CentOS 8 Linux, to enable the yum versionlock plugiun

yum install yum-utils.noarch


How to log every Linux executed command by every running system program to separte log via rsyslog for better server Security and audit trails

In case if by default log is not configured for snoopy,
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Distribution Snoopy output location Notes
CentOS /var/log/secure  
Debian /var/log/auth.log  
Ubuntu /var/log/auth.log  
(others) /var/log/messages (potentially, could be elsewhere)

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