This guide will show you how to increase the security of an Invision Power Board (IPB) installation. We’ll walk through practical examples for you to follow to harden IPB, reducing your attack surface.
There are a lot of insecure default options which unless modified will put you at a higher risk of being compromised by an attacker. Here we will outline what should be modified to increase security of IPB.
Yellowdog Updater Modifier (yum) is an RPM based package manager which is used to install and update packages in various Linux distributions including CentOS, RHEL and Fedora.
Yum is quite powerful as it’s capable of automatically resolving dependency issues, and is similar to other package managers such as ‘apt-get’ in Debian based distributions.
These examples should serve as a useful introduction, guide or cheat sheet style resource for how to use the yum command in Linux.
The ‘history’ command available in Bash can be used to simply display your shell history, however there’s also a whole lot more that you can do with it, which we’ll demonstrate here.
Bash history allows us to quickly see what has been executed previously on a system, allowing you to hold users at least somewhat accountable for their actions (more on this later). It’s also useful if you’ve run something before and forgot the command, I can’t begin to tell you the number of times that I’ve done this!
Security Enhanced Linux (SELinux) is enabled and running in enforcing mode by default in CentOS/RHEL based Linux operating systems, and with good reason as it increases overall system security.
Despite this there may be times when you want to temporarily or permanently disable SELinux, which is what we’ll cover here.
Normally resetting the root password is a simple task if you’re logged in already with root privileges, however if you forget the password and need to change it things become a little more difficult.
The process has changed from CentOS/RHEL (Red Hat Enterprise Linux) version 6 to 7, as previously you would boot into single user mode and then change the password as root. From version 7 the equivalent modes are the rescue or emergency targets, however these require the root password before you can do anything which doesn’t help us here, so we’ll take you through the new process to change the lost root password.
This is also a task that you will need to know how to perform for the RHCSA exam.
Earlier this month Microsoft announced that PowerShell had been open sourced and would be available for use in Linux. As a result of this, PowerShell is now available for Ubuntu 14.04 and 16.04, CentOS/RHEL 7, and macOS 10.11.
If your first thought is along the lines of “who would use this abomination?”, then you’re in good company. My best thought at who this is targeted towards is the Windows system administrator that needs to be able to manage Linux systems as they are likely already quite familiar with PowerShell and perhaps unwilling to change.
Personally I’d look at using a tool such as Puppet for managing systems running various operating systems, however here’s how you can install PowerShell in Linux should you want to take this path.
This guide will show you how to add a Nessus scanner into Tenable’s SecurityCenter using certificate based authentication, rather than standard username and password authentication.
In this example we will be upgrading from an older instance of the ejabberd-15.04 XMPP server to the current latest version ejabberd-16.06. Operating system specific packages such as RPM and DEB files were not provided until ejabberd-15.06, so our existing instance was not installed with the RPM file but instead from the binary file, meaning there is no existing ejabberd RPM installed for us to simply upgrade.
While this upgrade is taking place on the same server, these steps can also be used to perform a migration from one server to another with a fresh installation of ejabberd, as the new version will install to a new directory.
Here we’re going to cover how to migrate an existing running instance of Tenable SecurityCenter from one Linux server to another.
I was not able to find great documentation around this process, and after contacting Tenable support for instructions I found that the steps provided were very basic and did not actually include everything needed, so I have documented everything that I needed to do here.
In Linux we can delete local user accounts with the ‘userdel’ command. Here we will cover some examples of using the various syntax options with userdel in order to remove a local user account in Linux.