Overly broad permissions can turn one compromised account into a much larger security problem. Learn how to reduce unnecessary access, review privileges, and apply least privilege across modern Linux systems. Review Linux Privileges×
Let’s run a few commands to disable or turn off the SELinux on Rocky Linux 8 using the command terminal. . SELinux is now the standard in the Linux environment when it comes to the use of mandatory access control. Initially, the system had a reputation for being difficult to configure and only usable for experts. Those days are over. SELinux can now also be used and configured by “ordinary” admins. Well, in a conventional system, there are many different programs that all need to run with root privileges in order to be able to do their job, but should not have full root privileges (why should Apache have access to the mail pool files, for example?). SELinux is based on the TE principle (Type Enforcement): all resources are assigned to specific domains and access rules are defined on them. In short- all files are labeled, i.e. assigned to a specific domain; this means, for example, that all files belonging to Apache can be assigned the “apache_t” type. The Apache binary is also plugged into this domain. If the rest of the system is set up correctly, Apache can only access the data that is in its domain; any access to files located within other domains (e.g. “postfix_t”) is prevented by the kernel. . Learn the simple steps to turn off SELinux on Rocky Linux 8 with easy commands for improved system control.. SELinux Configuration, Turn Off SELinux, Rocky Linux Administration. . Brittany Day
Want to make dealing with SELinux considerably easier? Learn about three semanage commands that will help you accomplish this while not disabling the critical security system in this quick tutorial. . I get it--SELinux is challenging, and when your applications or services are prevented by the security layer, your first inclination is to set it to either Disabled or Permissive . In a time when security is at a premium, you can't afford to make that change, else you risk the security of your entire system or your network. You don't want that. Instead of putting everything at risk, why not make use of a tool that can help you out? That tool is semanage, which is the SELinux policy management tool. With semanage, you can adjust file contexts, port contexts and booleans, which will go a long way to help you make things workable, while not disabling the security system. . Unlock the power of SELinux using semanage commands for a fortified security stance while keeping your systems operational. Discover best practices in this comprehensive tutorial.. SELinux Management, semanage Commands, Security Configuration. . Brittany Day
Linux servers are already extremely secure by default that’s why 100% of supercomputers, most of the top 1 million servers , and top 25% of websites on the internet run on Linux. Besides having security tools in place, users should follow a few steps to further secure Linux servers. Learn about 10 steps you should take to secure your servers in this tutorial. . As we all know nothing is perfect. Things can go wrong if proper precautions are not taken. Once in a while, Linux tools encounter serious vulnerabilities and due to the nature of these tools (open-source), all tools quickly receive security fixes. When it comes to compromising a Linux server, most of the time users’ actions are responsible for it. After the compromise, we get to know the compromise could easily be prevented by implementing a simple firewall rule. The link for this article located at Linux and Ubuntu is no longer available. . Discover key measures for boosting the protection of your Unix-based server by utilizing effective strategies and recommended guidelines.. Linux Security Tips, Server Hardening, Best Practices for Open Source Security. . Brittany Day
Ever wanted to set up a robust, manageable and capable network monitoring system? How about one that is free to download? Look no further than Nagios with this HowTo from Rainer Brunold at Novell. With these basic steps you'll be able to pin down movement on your network in no time: Server Preparation Software Download and Extraction Security Preparation Software Compilation and Installation Installation of Plugins Configuration Apache Security Preparation Apache and Nagios Startup Testing and Next Steps Take Nagios for a spin and look out for more of the same soon! . The link for this article located at Novell is no longer available. . Explore streamlined approaches to configure Nagios for peak network surveillance and practical management techniques.. Nagios Monitoring, Network Management, Service Monitoring. . LinuxSecurity Contributors
For the Linux novice, installing a new build can be a daunting task. This chapter will help you figure out what you need and what you don't. Even Linux pros will find some tips on configuring a build that can help enhance security.. . Discover crucial guidelines for setting up Fedora 3 to ensure a safe and user-friendly experience for everyone involved.. Fedora Installation, System Configuration, Linux Security Tips, User Setup. . Anthony Pell
The first step to an attack is to see what services a server is running, which is done with a port scan of the server.. A cracker will usually first look to see what services a target is running and go from there to attempt to break into the target server. Doing a port scan, crackers go through all the common ports on a system looking for possibly flaws in the configuration or for a service with a known vulnerability. PortSentry is a program designed to detect and respond to port scans against a target host in real-time. It can run on multiple TCP and UDP sockets at once, detect stealth scans, report scan attempts to a local or remote logging facility, and take defensive actions against the attacker. Installation First, download PortSentry from here. Then, run: tar xvzf portsentry-1.0.tar.gz cd portsentry-1.0 make linux make install If you have any problems with this, read the portsentry-1.0/README.install file. Configuration The PortSentry configuration file is located at /usr/local/psionic/portsentry/portsentry.conf. If needed, change the configuration where necessary to suit the needs of the system. Blocking scans is recommended, but if ipchains is used, the -l options should be used with care because it can be used in a denial of service attack by filling up your /var partition. Once finished editing the configuration file, add any addresses that shouldn't be reported for scanning to the /usr/local/psionic/portsentry/portsentry.ignore file. At the very least, all local interfaces should be listed in the file along with 0.0.0.0. Here is an example portsentry.ignore file. 127.0.0.1 0.0.0.0 192.168.1.6 Using PortSentry The different options for running PortSentry are: portsentry -udp portsentry -tcp portsentry -audp portsentry -sudp portsentry -atcp portsentry -stcp With either the -udp or the -tcp options, normal scan detection is done. With -sudp and -stcp, normal stealth scan detection is done. With -audp or-atcp, advanced stealth scan detection is done. It is recommended that two instances of PortSentry are running. /usr/local/psionic/portsentry/portsentry -sudp and /usr/local/psionic/portsentry/portsentry -atcp Adding the above two commands to /etc/rc.d/rc.local will have PortSentry automatically started at boot up. More Information Check out this article. Also, here is an article about setting up PortSentry to log to a separate file. At DEFCON 7, the author of PortSentry made a presentation with the slides that are shown here. . Learn to harness the power of PortSentry for instantaneous threat identification and defense against port scanning attempts.. PortSentry Usage, Attack Detection Tool, Network Scanning Protection. . Anthony Pell
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