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Adding a malicious system call to the Linux kernel

Posted by Tariq • Thursday, December 11. 2008 • Category: Security
Today I am adding a malicious system call to the Linux kernel which will allow the caller to do something they cannot normally do in user mode. When attacking a Linux box our goal is usually to become root; as root we can do anything we like, so the system call I will add to the Linux kernel gives the caller real and effective user ids of zero.

There are relatively few tutorials out there on how to do this, unfortunately there a little differences between versions of Linux that can easily stump beginners, so this tutorial tries to give you an environment which you can easily replicate using a virtual machine and go through the tutorial.

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