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

Unix security audit: Perform an audit in 3 minutes

Unix security audit: Perform an audit in 3 minutes Want to know the vulnerabilities of a Unix/Linux system is in just 3 minutes? How? Perform a scan with Lynis, the open source Unix security audit tool! Lynis Lynis is open source software (GPLv3), released in 2007 and a popular choice by many security professionals and system administrators. Hundreds of downloads in the first week of each release and with a lot of community feedback, Lynis is the right tool for […]

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Become a Linux Auditor: What to know?

Linux Auditor: What to know? Now open source software and platforms are very common, the need for knowledge in this area is increasing. Becoming a technical auditor with specialized knowledge about Linux, might be a clever move. Technical When specializing in Linux, the auditing area is already more technically oriented, instead of the processes. A true Linux auditor knows more than the basics of Linux. In-depth knowledge is required, like what file systems are common, how permissions are arranged, popular […]

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Auditing Linux: what to audit?

Auditing Linux: what to audit? In this article we answer the big question on Linux systems “what to audit?”. Where do you start and what is useful to audit? We apply our three C‘s in this article to determine what we should look for when auditing a Linux system. Current state What is the current state of the system and how does it compare to previous time? Ideal situation: compare current state of the system with a predefined baseline or […]

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Central audit logging: Configuration and collecting of Linux audit events

Central audit logging: Configuration and collecting Linux audit events This guide is to help our users of the Lynis Enterprise Suite to configure a central node to receive Linux audit events. It provides some pointers on how to do a quick set-up, to store and forward events. This information is very valuable for forensic investigations and intrusion detection. Configure the server First start by configuring the server. Since this is a central log host, it should have enough disk capacity […]

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Become a Linux auditor: tips to start with auditing the Linux platform

Become a Linux auditor: tips to start with auditing the Linux platform This guide helps people new to the Linux platform to get a grasp on how the system works. Whenever you are an IT auditor, or simply want to know more about the basics, this guide helps you in determining where to start an audit. Processes Each operating system consists of smaller running processes. In case of Linux this is true as well and can be displayed with the […]

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How to: Using Lynis plugins

Within this “how to” we explain when and how to use Lynis plugins. What are plugins? Plugins are small extensions to an existing program. Also Lynis supports the use of external plugins to extend functionality. Lynis plugins are written in shell script and might use system binaries or external binaries to perform additional checks. The big difference between custom tests and plugins in Lynis, are the goal of the tests. If some logic function checks a value and can inform […]

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Linux Audit Framework: using aureport

Linux Audit Framework: using aureport The Linux audit framework logs events, as specified by the configured watches. To extract particular events we can use the ausearch or aureport tools. The latter is the one we will focus on in this article, to get the most out of the tool. Aureport The aureport utility can be executed without any parameters. It will then extract all audit events available from the log. Since the audit log can be very big, it might […]

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Linux server security: Three steps to secure each system

Linux server security: Three steps to secure each system Determining the level of Linux server security can only by measuring the actual implemented security safeguards. This process is called auditing and focuses on comparing common security measures with the ones implemented. While there is almost no system with all possible safeguards implemented, we still can determine how well (or badly) the system is protected. Security is about finding the weakest link(s) and associate risk with each weakness. Depending on the […]

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Linux audit log: dealing with audit.log file

Linux audit log: dealing with audit.log file The Linux kernel audit framework consists of several components including a daemon, control client, audit rules and Linux audit log. In this article we take additional measures to protect the audit.log file. Aureport The first useful utility to parse the audit.log is aureport. Without parameters it will give a summary of all events. This includes the files, users, audit keys and also items like suspicious events (anomalies). Each sub item can be read […]

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Linux kernel security and how to improve it

Every system is as strong as its weakest link. In the case of an operating system like Linux, one weakness in the kernel could result in a security breach. This article covers the Linux kernel features and how they work. Kernel features Live kernel patching As the kernel is similar to other software, it receives updates to improve it. Now and then a security weakness is discovered in one of the subsystems of the Linux kernel. This means that Linux […]

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Lynis for Auditors: Linux and Unix auditing

Lynis for Auditors: Linux and Unix auditing Auditing on Linux Although Unix and Linux based systems are not new, getting an extensive knowledge of the operating system takes years of practice. Even then, with all changes it might be hard to keep up, especially when being an auditor. Examples of these are the differences between package managers, the way services are started and where binaries or configuration files are located. But no worries, there is help! Why Lynis? The goal […]

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Conducting a Linux Server Security Audit

Conducting a Linux Server Security Audit Auditing a system can be a time-consuming job, which is no different when conducting a Linux server security audit. Within this article, we give some highlights regarding the audit and tips to automate them by using Lynis. The business goal Before auditing any system, determine the business goal of the system. How critical is this system for doing business? What if the system goes down? Usually each system has a clear role or multiple […]

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Difference between Lynis and Lynis Enterprise

Difference between Lynis and Lynis Enterprise People wonder about the main differences between Lynis and the Lynis Enterprise version. In this article we have a look on what both products are and how you can choose between the two. Lynis Lynis is a security auditing tool for Linux and Unix based systems. With its GPLv3 license it’s open source and freely available. The tool was first released in 2007 and has undergone a lot of development during the years. Lynis is […]

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Open source vulnerability scanner for Linux systems – Lynis

Open source vulnerability scanner for Linux There are several open source vulnerability scanners for Linux, like OpenVAS. While tools like these are powerful as well, we will have a look at Lynis, our auditing tool to detect vulnerabilities of Linux and Unix systems. Why is it different than others and how can it help you in securing your systems? Vulnerabilities Every piece of software will have sooner or later a vulnerability, a minor or major weakness which can be abused […]

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What is a security audit?

What is a security audit? In the world of compliance, reported break-ins on the news and many security incidents, it’s common to see a security audit showing up sooner or later. Still, many people in our field don’t like them. But what is a security audit and why should we actually embrace them? Why audit? Auditing has a simple goal: check if something is configured according to best practices, a baseline or a preferred state. In an ideal situation these […]

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