Ubuntu Server Hardening Guide: Quick and Secure

Ubuntu Server Hardening Guide The system hardening process of a server is critical during and after installation. It helps the system to perform its duties properly and stay secured as much as possible. This blog post about Ubuntu system hardening will look into the most critical steps to take first. More detailed system hardening steps can be added on top of these, for which we will share some tools and guides at the end. As most security guides only tell […]

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Discover to which package a file belongs to

Determine the package a file belongs do Sometimes you want to know the related package of a file, before installation, or when it is already there. This is of great help during system hardening or general system cleanups. In this article we have a look at several ways to determine the relationships between files and the package they belong to. CentOS, Fedora, RHEL Show files per installed package To show what files are in a package, use the rpm command. rpm -ql […]

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How to solve an expired key (KEYEXPIRED) with apt

Updating expired keys on Debian and Ubuntu 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. root# 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 […]

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How to Disable “System program problem detected”

Quick Ubuntu Tips: System program problem detected   Sometimes programs crash, usually for a different variety of reasons. While it is good to do research and find the underlying cause, sometimes you simply want to disable any reporting. Clean up /var/crash First thing to do is check your /var/crash directory and see if there are any “crash” files. These are just normal text files and include details about a process. If you have a process crashing regularly, you most likely want to […]

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Linux Vulnerabilities Explained: From Detection to Treatment

Linux Vulnerabilities Explained 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 GNU/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. The goals? Know which vulnerabilities exists […]

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Using unattended-upgrades on Debian and Ubuntu

Using unattended-upgrades on Debian and Ubuntu 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. root@system:~# apt-get install unattended-upgrades If you are […]

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What’s New in Lynis 2: Features

Lynis 2.x Features Lynis 2.x will bring security auditing of Linux and Unix systems to a new level. In this blog post we share some exciting new features. Release of Lynis 2 is planned for February 2015. Overview: History Lynis 2.x Plugins Systemd Support File Integrity Monitoring Containers & Virtualization Operating Systems Focus on Simplicity Free and Commercial Support   History Lynis has been created in 2007, as a follow-up on the well-known tool Rootkit Hunter (rkhunter). Both tools are […]

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How to solve Shellshock on Debian and Ubuntu

Protect against Shellshock For Debian and Ubuntu 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 efforts 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 […]

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