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

What is the ‘toor’ user on FreeBSD?

What is the ‘toor’ user on FreeBSD? Linux and *BSD systems have by default a root user installed. As it has a user ID of zero (0), it gains the highest level of permissions from the kernel. On FreeBSD systems, there is also the ‘toor’ user, with the equal high-level user ID of zero. It is simply the reversed version of ‘root’, and installed as a backup account. By default, it has no shell assigned, so it can’t log in. […]

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Understanding Linux Privilege Escalation and Defending Against It

Linux Privilege Escalation How it works, and what steps you can take to protect yourself Privilege escalation in another term for the elevation of permissions, of a normal user. This means that a normal user on Linux can become root, or get the same permissions as root. This can be authorized usage, with the use of the su or sudo command. It can also be unauthorized, for example when an attacker gains too many permissions. In this case often with […]

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Troubleshooting Linux Time Synchronization with NTP

Time Synchronization The network time protocol helps computer systems to synchronize their time. We know this protocol by its shorter name NTP. In the past, it was not really a big issue if your system was a few minutes off. This changed with the interconnected world we are now living in. One of the better examples is networks relying on the authentication protocol Kerberos. If your system time is not correct, you may not be able to authenticate. This is because […]

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The Non-Technical Changelog: Insights of 6 Months Development

The Non-Technical Changelog Lessons learned between our last and current release The Lynis project team is proud to announce a new release of our security auditing tool. With months of work and a variety of changes, we bumped up the version to a “zero release” (2.2.0). The technical changelog is included in the download. We consider it to be a stable release, yet ask all to test it first. Being the original author of Lynis, there is an additional background […]

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Upgrading External Packages with unattended-upgrade

Upgrading External Packages with unattended-upgrade The unattended-upgrade tool is a great way to keep your system automatically updated. While you might not always want to do that for all packages, it definitely can be a great way to assist in your security efforts. In that case, tell it to track security updates and install the related packages. If you are using third-party packages (e.g. via PPAs), the system has no idea about security updates for those packages. So you need […]

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Find and Disable Insecure Services on Linux

Insecure Services on Linux The world has changed a lot in the last era, especially when it comes to computing. This applies also to the services we run on our Linux systems. Some of these services (like rlogin), were previously the defacto tools to do administration. Now they are considered to be bad and insecure. What makes a service insecure? Services can become insecure when they have characteristics like: No (or weak) authentication No (or weak) encryption Insecure protocols Running as […]

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Mosh, the SSH Alternative Option for System Administration

Reasons to use Mosh instead of SSH Mosh, or mobile shell, is the ideal tool for remote system administration. While SSH is great, Mosh beats it in several areas. Let’s dive into the reasons why it makes sense to learn about Mosh. Pros Session Resumption Remember the last time your connection was interrupted? It it frustrating and sometimes even leads to losing some of your work. The stable TCP connection is not always a blessing. Mosh comes to the rescue, especially […]

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Best Open Source Security Tools of 2015 (and 2016)

Best Open Source Security Tools Always looking for a better tool to help you in your work? If there is one website who knows what is happening in the field of security tools, it is ToolsWatch. The site covers new tools, and promotes existing projects when they release a new version. Every year ToolsWatch ask their readers to vote for their favorite security tool. Here are the recent results of 2015: 01 – OWASP ZAP – Zed Attack Proxy Project (+1↑) […]

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