Increase kernel integrity with disabled Linux kernel modules loading

Increasing Linux kernel integrity Disable loading kernel module on Linux systems The Linux kernel can be configured to disallow loading new kernel modules. This feature is especially useful for high secure systems, or if you care about securing your system to the fullest. In this article, we will have a look at the configuration of this option. At the same time¬†allowing legitimate kernel modules to be loaded. Disable kernel modules Newer kernel modules have a sysctl variable named kernel.modules_disabled. Sysctl […]

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Security Integration: Configuration Management and Auditing

Configuration Management and Auditing Increased strength when combining tools for automation and security of IT environments Tools like Ansible, Chef, and Puppet are used a lot for rapid deployment and keeping systems properly configured. These tools in itself are great for ensuring consistency over your systems. So what is Configuration Management? Configuration management is the art of keeping systems properly configured. Usually companies start small, which equals manual configuration. Each time a new system is deployed, it is configured manually. […]

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Password Security with Linux /etc/shadow file

Password Security on Linux Using the /etc/shadow file Linux systems use a password file to store accounts, commonly available as /etc/passwd. For additional safety measures, a shadow copy of this file is used which includes the passwords of your users. Or actually hashed password, for maximum security. An example of a password entry in /etc/shadow may look like this: user1:$6$6Y/fI1nx$zQJj6AH9asTNfhxV7NoVgxByJyE.rVKK6tKXiOGNCfWBsrTGY7wtC6Cep6co9eVNkRFrpK6koXs1NU3AZQF8v/:16092:0:99999:7::: For proper display, let’s split this up in several fields: user1 $6$6Y/fI1nx$zQJj6AH9asTNfhxV7NoVgxByJyE.rVKK6tK<truncated> 16092 0 99999 7 <nothing> <nothing> Field explanations […]

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PCI DSS (v3) Linux: Creation and deletion of system-level objects (10.2.7)

PCI DSS (v3) Linux: Creation and deletion of system-level objects (10.2.7) Some areas are within the PCI standard are definitely not directly clear when reading the description. Section 10.2.7 is one of them. It talks about the creation and deletion of system-level objects and specifically the ability to log them. System-level objects? The guidance in 10.2.7 speaks about malware and mentions database related items. That does not make auditing very obvious, as malware usually targets binaries. Therefore we have to […]

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An Introduction Into Linux Security Modules

An Introduction Into Linux Security Modules Background Like normal kernel modules, security modules extend the basic functionality of the Linux kernel. The need for a modular structure was proposed when SELinux was being introduced. There was a little discussion to use modules or not, as SELinux was the only one being available. Some people proposed apply it as a kernel patch, but in the end Linux creator Torvalds, decided to make this type of functionality modular. The first security module […]

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Docker Security: Best Practices for your Vessel and Containers

Docker Security Everything you need to know about Docker security.   Introduction into Docker Docker became very popular in a matter of just a few years. Operating systems like CoreOS use Docker to power the system by running applications on top of their own lightweight platform. Docker in its turn, provides utilities around technologies like Linux container technology (e.g. LXC, systemd-nspawn, libvirt). Previously Docker could be described as the “automated LXC”, now it’s actually even more powerful. What it definitely […]

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PCI DSS (v3) Linux: Invalid logical access attempts (10.2.4)

PCI DSS (v3) Linux: Invalid logical access attempts (10.2.4) PCI describes in control 10.2.4 to monitor for “invalid logical access attempts”. Another way of saying to monitor attempts which are not allowed, like accessing a file you are not supposed to. Another indication might be brute force attempts to log in, which result in several failed logins. To monitor for invalid access attempts, we can use the Linux audit framework. This framework has been created and maintained by Red Hat […]

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PCI DSS (v3) Linux: Logging of administrative actions with root privileges (10.2.2)

PCI DSS: Logging of administrative actions with root privileges Companies who need to comply with the PCI DSS standard need to log all actions which are executed by the root user, or similar administrative privileges. 10.2.2 Verify all actions taken by any individual with root or administrative privileges are logged. The Linux kernel allows to monitor commands. By configuring the Linux audit framework, we can monitor the right system calls and create an audit trail. Configure logging To capture executed […]

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