Debian
Apt cheat sheet
The package manager apt gots much more options than one could think. In this cheat sheet they get uncovered.
Summary
Managing packages
Discover to which package a file belongs to
With the right Linux software tools, it is easy to find to which package a file belongs. Or the opposite, what files are part of an installed package.
Summary
Discover quickly which file(s) and package are matched together.
How to solve an expired key (KEYEXPIRED) with apt
Software updates and package management is easy, until you get a KEYEXPIRED message. In this article we should how it happens and the way to solve it.
Summary
Software updates and package management is easy with systems based on Debian or Ubuntu. Just apt-get update (or apt update) and run an upgrade. But sometimes you may encounter the following situation: a KEYEXPIRED message. KEYEXPIRED message # apt-get update && apt-get upgrade Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [94.5 kB] Hit:2 http://nl.archive.ubuntu.com/ubuntu xenial InRelease Get:3 http://nl.archive.ubuntu.com/ubuntu xenial-updates InRelease [95.7 kB] Hit:4 http://nl.archive.ubuntu.com/ubuntu xenial-backports InRelease Hit:5 https://packages.cisofy.com/community/lynis/deb stable InRelease Get:6 http://nl.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [373 kB] Ign:7 http://nginx.
Linux vulnerabilities: from detection to treatment
How to deal with Linux vulnerabilities? This article shares the insights, methods, and tools to help with detection and prevention on Linux systems.
Summary
If you worked with a computer the last decade, you know the importance of keeping your software up-to-date. Those who don’t, are stacking up vulnerabilities, waiting for them to being exploited by others. Although Linux and most software are open source and can be reviewed, security flaws in software packages remain. While it isn’t easy to close every vulnerability on your system, we can at least create a stable process around it.
Determine Processes Which Need a Restart with checkrestart/needrestart
Just patching software packages is not enough. We cover some tools to determine which processes need a restart to complete software patch management.
Summary
Proper software patch management helps reducing weaknesses on your systems. But even if you patched an outdated system, old processes and libraries can continue to run in memory. For example when a library is updated, an active program might still use the old version. To really finish the process of software patching, we have to do more. This includes preparation, performing the update and finally check if we need a restart of software components.
Using unattended-upgrades on Debian and Ubuntu
To counter the biggest threat to software packages, Debian and Ubuntu based systems can use unattended-upgrades, to install security patches automatically.
Summary
To counter the biggest threat to software packages, they should be updated on a regular basis. Vulnerabilities are discovered on a daily basis, which also requires we monitor daily. Software patching takes time, especially when testing and reboots are needed. Fortunately, systems running Debian and Ubuntu can use unattended-upgrades to achieve automated patch management for security updates. Installation With most software packages, unattended-upgrades has to be installed. apt install unattended-upgrades
How to solve Shellshock on Debian and Ubuntu
Also Debian and Ubuntu are vulnerable for Shellshock vulnerability in Bash. That's why it is important to run apt update and perform an upgrade of Bash.
Summary
Protect against Shellshock Shellshock is a serious software weakness, or vulnerability, in Bash. This shell is used on almost all Unix based systems, including Debian and Ubuntu. As it can be used without much effort and remotely exploit systems, it has a maximum vulnerability score according to CVSS. Upgrade Bash First update the software repository with apt-get, using the update parameter. apt-get update && apt-get install -only-upgrade bash Your system should now have a newer version of bash.
Check for a required reboot on Debian and Ubuntu systems
Debian based systems, like Ubuntu, need sometimes a reboot as well. We have a look on determining if a required reboot is needed and due to what packages.
Summary
Administrators of Debian-based systems know they have to reboot their systems, just like any other Linux distribution. However, why is the reboot needed? Could we monitor for which systems need an actual reboot? Required restart required? This Ubuntu system needs a restart Required reboot Software can contain issues, which we call bugs. Most bugs are just annoying if you encounter them and can be fixed by upgrading to a newer version of the software.