I’m writing this post because I often hear that kernel exploitation is intimidating or difficult to learn. As a result, I’ve decided to start a series of basic bugs and exercises to get you started! Prerequisites Knowledge of the Linux command line Knowing how to read and write basic C may be beneficial Being able to debug with the help of a virtual computer or another system Able to install the kernel module compilation build requirements A basic understanding of the difference between userland and kernelland could be helpful Having a basic understanding of assembly can be beneficial for future episodes For this part, I wrote a simple Linux character device , /dev/shell . This driver will take two arguments, uid and cmd , and it will execute the cmd command as the specified uid . To understand how this driver works, I’ll explain a few things! . . Dive into the fundamentals of kernel exploitation and enhance your skills with straightforward Linux challenges and practical exercises.. Kernel Exploitation, Linux Challenges, C Programming. . LinuxSecurity.com Team
Every self-respecting Linux guru should be familiar with firewalls and how to install and configure them. With this in mind, Linux gurus also should be curious about how firewalls function and how to build a firewall of his or her own. . . .. Every self-respecting Linux guru should be familiar with firewalls and how to install and configure them. With this in mind, Linux gurus also should be curious about how firewalls function and how to build a firewall of his or her own. Explaining exactly these two things is the goal of this article. Here, we attempt to write a firewall in less than 60 lines of C code. As impossible as this may sound, it actually is quite simple to do using the power of Linux kernel modules and Netfilter. Netfilter is a packet filtering subsystem in the Linux kernel stack and has been there since kernel 2.4.x. Netfilter's core consists of five hook functions declared in linux/netfilter_ipv4.h. Although these functions are for IPv4, they aren't much different from those used in the IPv6 counterpart. The hooks are used to analyze packets in various locations on the network stack. The link for this article located at Linux Journal is no longer available. . Learn how to build a personal firewall in Linux using Netfilter with this sample C code that blocks incoming connections on a specified port. Linux Firewall, Netfilter Setup, Packet Filtering, Network Security Guide. . Anthony Pell
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