Category: System Administration

(last updated at ) Malware, System Administration 52 comments

Installing ClamAV on CentOS 7 and Using Freshclam

Install and Configure ClamAV on CentOS 7 Including the usage of Freshclam   To get ClamAV on CentOS installed, we have to use the EPEL repository (Extra Packages for Enterprise Linux). Fortunately, the Fedora project provides this with an easy installation. Unfortunately the default configuration is not properly working. In this post we collect some of the issues and required changes. Let’s start with installing the EPEL support. yum install epel-release Next step is installing all ClamAV components. yum install […]

Read more
System Administration 5 comments

Determine Processes Which Need a Restart with checkrestart/needrestart

Determine which processes need a restart after software patching 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 But even if you patched an outdated system, old processes and libraries can continue to run in memory.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 […]

Read more
(last updated at ) SSH, System Administration One comment

Using SSH keys instead of passwords

Using SSH keys instead of passwords Linux systems are usually managed remotely with SSH (secure shell). Still many administrators are using passwords, instead of keys. Keys not only boost security, it also makes managing systems much easier. Instead of entering your password for each server, you only have to do it once per session. When managing several systems per day, you will be wondering why you ever used password based authentication before. Creating the key Depending on your desktop platform, […]

Read more
(last updated at ) Performance, System Administration, Web 4 comments

Optimize SSL/TLS for Maximum Security and Speed

Optimize SSL/TLS for Maximum Security and Speed High Goal Setting Recently we changed our corporate website into a “HTTPS only” version. Most of the content is not secret information, still we have some sensitive areas. The ordering section and downloads, and additional our portal. While some areas were already covered with a lock, we felt it was time to make the jump to cover it all. Additionally, we believe that we doing everything we can on our website, practicing security […]

Read more
(last updated at ) Automation, Software, System Administration 3 comments

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 […]

Read more
(last updated at ) System Administration 2 comments

Updating all OpenBSD packages with pkg_add

Using pkg_add Keeping your systems stable and secure Every system needs to stay up-to-date with its packages, including OpenBSD. Most OpenBSD users already use pkg_add for the installation of packages. This utility can also be used for package upgrades. Option 1: Use /etc/installurl Newer OpenBSD versions use the file /etc/installurl to select the mirror for pkg_add. Option 2: PKG_PATH The first thing to do is defining your PKG_PATH. This will usually be the address of a FTP or HTTP server, which […]

Read more
(last updated at ) Software, System Administration 2 comments

Software Patch Management for Maximum Linux Security

Linux Patch Management Maximum Linux security with proper software patch management   Software upgrades are almost as old as the first lines of software code. Still companies struggle to properly update software, also when it comes to security patching. In this article we have a look at the reason behind patching and some methods to keep your systems humming, with fresh packages. Why Update? To most of us, it instantly makes sense to keep the software on your systems up-to-date. […]

Read more
(last updated at ) Accounting, Auditing, System Administration, Troubleshooting One comment

Linux Audit Framework 101 – Basic Rules for Configuration

Starting with Linux auditing can be overwhelming. Fortunately, there is a great feature in the Linux kernel to watch events and log them for us. To give you a quick start to use the Linux Audit Framework, we have collected some basic rules for configuring the audit daemon and its rules. Main Configuration By default the configuration values in /etc/audit/audit.conf are suitable for most systems. If you know your system is very low or very high (e.g. mainframe) on resources, […]

Read more
System Administration 2 comments

tlsdate: The Secure Alternative for ntpd, ntpdate and rdate

tlsdate The Secure Alternative for ntpd, ntpdate and rdate The common protocol to synchronize the time, is named Network Time Protocol, or NTP. While this protocol works great for synchronizing systems to one or more multiple time sources, it is not always easy to set-up. One alternative is using tlsdate, a secure replacement to keep your systems in sync. About the Project The software is written in 2012 by Jacob Appelbaum and can be found at GitHub: tlsdate. With the […]

Read more
(last updated at ) Linux, Monitoring, System Administration 9 comments

How to check if your Arch Linux system needs a reboot

Arch Linux reboots How to check if a reboot is needed By default Arch will install the kernel in /boot with the name vmlinuz-linux. To determine if the system is running the latest kernel, we can compare the running kernel and the one on disk. Running kernel One way to determine the running kernel is with the uname command. By default installed and with the -r parameter it will provide the kernel release version. [root@archlinux ~]# uname -r 3.17.4-1-ARCH Kernel […]

Read more
Auditing, System Administration, Vulnerabilities 4 comments

Perform NetBSD security audit with pkg_admin

Perform NetBSD security audit Security audit of NetBSD software packages with pkg_admin NetBSD is especially known for it’s diverse platforms it can run on. What is less known is the ability to audit the installed packages. In this article we have a look on how to audit NetBSD and ensure the file integrity of your packages. Performing a security audit is easy, as long as you use the right tool! Packages When using packages, their metadata will be installed in […]

Read more
(last updated at ) System Administration 2 comments

Finding boot logs in systemd journals

Finding boot logs in systemd journals Systemd used a binary log to store information about specific events. These events include the boot sequence and the related output. In this article we have a look at finding our boot logs in systemd journals. Binary logging When using systemd, boot data is stored in journals, a binary format. There is big benefit of saving boot data in a binary format: log information of each boot can be stored separately, linked to other […]

Read more
Network, System Administration Leave a comment

Alternative for netstat: ss tool

Alternative for netstat System administrators and security professionals searching for listening ports on a server, are definitely familiar with the netstat command. However, newer distributions do not have the tool default installed anymore. Time to start using ss besides our beloved netstat command. ss Socket statistics, or ss for short, is an easy replacement command for netstat. One way to use it, is with parameters ss -aut -a: show listening and non-listening sockets -u: show UDP -t: show TCP [root@archlinux […]

Read more
(last updated at ) Hardening, Linux, System Administration Leave a comment

Linux capabilities 101

Security of Linux systems and applications can be greatly improved by using hardening measures. One of these measures is called Linux capabilities. Capabilities are supported by the kernel for some while now. Using capabilities we can strengthen applications and containers. Unfortunately, this powerful tool is still underutilized. Time to change that! This article helps to understand and apply them. What are Linux capabilities? Normally the root user (or any ID with UID of 0) gets a special treatment when running processes. […]

Read more
System Administration One comment

Auditing systemd: solving failed units with systemctl

Auditing systemd Solving failed units with systemctl Systemd is an alternative service manager to the more traditional init system. To ensure the system is healthy, failed units should be investigated on a regular basis. Sooner or later a unit might fail and showing up the systemctl listing. In this article we have a look at how to solve it. Why do services fail? During the start of the system, enabled services are started and queued to be executed. Most processes […]

Read more
123