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Linux Security & Hardening Tutorial

With access to the full logs via Log Explorer, you can now perform a search to find specific requests. Worth noting that /proc/kallsyms and the kernel log are not the only sources of potential kernel pointer leaks. There is a lot of legacy in the Linux kernel and [new sources are continuously being found and patched]. That’s why it is very important to stay up to date with the latest kernel bugfix releases. There are some flexibility downsides though, as we can’t “retrofit” a new kernel module for an already released kernel (for example, for a new piece of hardware we are adopting).

Linux Hardening and Security Lessons

With other legacy SWG and firewall tools, the process of blocking traffic by specifying only the well known port number (for example, port 22 for SSH) can be both insecure and inconvenient. For example, if you used SSH over any other port it would not be filtered properly, or if you tried using another protocol over a well known port, such as port 22, it would be blocked. An argument could also be made to lock down the destinations to only allow incoming connections over certain ports, but companies don’t often control their destination devices. Its capabilities and the volume of messages routed have grown significantly since launch. We know that application security logs are only part of the puzzle in understanding what’s going on in your environment. A 403 error occurs when a user’s request to a particular site is blocked.

Authentication

Each Log Explorer dataset is stored on a per-customer level, just like Cloudflare D1, so that your data isn’t placed with that of other customers. In the future, this single-tenant storage model will give you the flexibility to create your own retention policies and decide in which regions you want to store your data. In the sampled logs view, you can see that most of these requests are coming from a common client IP address. As a SOC analyst, your job is to monitor and respond to threats and incidents within your organization’s network.

Messages are encrypted in transit when the connection is made over TLS, while messages sent over unencrypted connections can potentially be read or modified in transit. Fortunately, the vast majority of messages received by Cloudflare’s email servers Linux Hardening and Security Lessons are made over encrypted connections, with just 6% sent unencrypted during February 2024. The summary and time series data for TLS usage are available through the Radar API. The share spiked several times throughout the month, reaching as high as 70%.

Learning

These are misconceptions, as Linux also requires diligent security practices. 2FA adds an extra layer of security by requiring two forms of identification before granting access. In Linux, it can be implemented using tools like Google Authenticator or Duo Security. Create a culture of high touch customer service in the area of Homeland Security and Emergency Management.

This is especially true if you are managing your MySQL server yourself. Alternatively, you could underblock and miss out on filtering your intended traffic, creating security risks for your organization. In order to power our rich analytics dashboards with fast query performance, we implemented data sampling using Adaptive Bit Rate (ABR) analytics. This is a great fit for providing high level aggregate views of the data.

Information Security (InfoSec)

JShielder is a security tool for Linux systems to make them more secure by adding system hardening measures. Each file is assigned an owner and a group and a set of file permissions. The Linux kernel uses file permissions as a first layer to see if a user is granted access to a particular file or directory. It also defines what type of access is granted, such as read-only access or more. Although there are several combinations possible, it is not fine-grained.

Linux Hardening and Security Lessons

The more changes, the bigger the risk that something will no longer work. Sometimes these changes might impact performance, but typically they may result in something like the inability to connect to a system, log in, or retrieve data from an application. Secure web servers by updating server software, configuring SSL/TLS for encrypted connections, implementing strong authentication methods, and regularly scanning for vulnerabilities. Kernel hardening involves securing the Linux kernel, the core of the operating system, against various types of attacks. This can be achieved through configuration changes, applying patches, and using security-focused kernel extensions.

Secure WordPress database: 13 MySQL security best practices (+1 bonus)

Therefore its original design has security flaws and is known to be able to bypass secure boot and potentially compromise system integrity. Secure boot is the cornerstone of any operating system security mechanism. The Linux kernel is the primary enforcer of the operating system security configuration and policy, so we have to be sure that the Linux kernel itself has not been tampered with. In our previous post about secure boot we showed how we use UEFI Secure Boot to ensure the integrity of the Linux kernel. Most Linux distributions use the modular framework named PAM, which is short for pluggable authentication module. The framework allows configuring most of the settings related to authentication, such as where to check that a user or account exists.

  • However, it’s also important that other Internet services begin to support and use IPv6, and this is an area where our recent research shows that providers may be lacking.
  • The Breach CTF virtual machines are all themed on the classic cult movie, Office Space.
  • While most changes are easy to undo, some might have a serious impact.
  • If you’re interested in using protocol detection or ready to explore more broadly how Cloudflare can help you modernize your security, request a workshop or contact your account manager.
  • So besides creating a new backup before you make changes, perform a test restore.