Passionate about Linux hardening, compliance, security management and new technologies.

How to use Lynis

How to use Lynis This article explains in a few quick steps how to start with using Lynis. A more extensive explanation can be found in the documentation of Lynis. Download Lynis: wget http://cisofy.com/files/lynis-version.tar.gz Unpack tarball: tar xfvz lynis-version.tar.gz This will unpack the tarball with a Lynis directory. Go into this directory: cd lynis-version When running Lynis for the very first time, just just the -c parameter. It will start the audit process and pauses after every batch of tests. […]

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Antivirus for Linux: is it really needed?

Antivirus for Linux The question regarding the need of antivirus for Linux is still a hot subject. Is it really needed or simply a nice-to-have? Within this article we have a look at antivirus for Linux and the alternative options. Malware Antivirus is a security measure to protect against malicious software, also known as malware. Most malware is still focused on Windows, followed by mobile devices and Mac OS. While there is malware for Linux, these pieces usually attack server […]

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How to secure Linux systems – Auditing, Hardening and Security

How to secure Linux systems Within this article we have a look on how to secure a Linux system. Focus of the article is providing tips regarding auditing, hardening and general security of Linux servers. Hardening Focus on minimizing By minimizing the footprint of the server, its data and users, we can more quickly determine if a system is running properly. Also risks will be reduced, as every part on a system might be something which can be sooner or […]

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Dealing with a compromised Linux system

Compromised Linux system Before we dive deep into this subject of dealing with a compromised Linux system, we have the answer the biggest question: how do we know we are compromised? Usually some signs are a clear give-away: The website hosted was altered and replaced with a “You have been hacked” page The system is missing essential binaries, or they all crash after executing Unauthorized users have been created and the system is hosting movies and music, which is not […]

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Auditing Linux: Software Packages and Managers

Auditing Linux: Software Packages and Managers No system can do its job without any installed software packages. However after installation of the system, or running it for a while, it often becomes unclear why some software was ever installed. This article looks at methods on auditing installed software, check for security updates and the related follow-up. Package managers To enable system administrators to properly manage software and upgrading them, Linux uses a package manager. This suite often consists of a […]

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Lynis Hardening Index

Lynis Hardening Index At the end of each Lynis scan the report will be displayed. This report will include the findings (warnings and suggestions) and general information like the amount of security tests performed. Additionally the location of the log file and report data will be displayed. Between all this information there is a “Lynis hardening index” displayed. This index is  unique to Lynis. The index gives the auditor an impression on how well a system is hardened. This number […]

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Securing Linux: Audit with Lynis (an introduction into auditing)

Introduction Securing a Linux system can take a lot of time. For this purpose we have written Lynis, a quick and small audit tool. It’s an open source tool and freely available. You just need root permissions and a common shell and you’re ready to do your first audit. The main audience for this tool is auditors, security professionals, penetrating testers and system administrators. First audit Most Linux distributions already have Lynis in their software repository. If not, then download Lynis […]

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Linux Audit: Auditing the Network Configuration

Introduction Within this article we have a look on how to audit and check the network configuration of Linux and other systems. The main focus is on gathering information and discover how systems are configured. By taking these steps we will do a manual audit. For efficiency reasons we suggest to use an automated tool like Lynis. Where to start? Each Linux distribution has their own way and files to configure the network. Therefore we look at the basic components […]

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