add link to blog post

Author: xcellerator

3_RootkitTechniques/3.3_set_root/README.md

@@ -4,6 +4,8 @@
 
 > Updated to use [ftrace](https://www.kernel.org/doc/html/latest/trace/ftrace.html) instead of directly modifying kernel memory
 
+> There is now a blog post explaining this module in more detail! Check it out [here](https://xcellerator.github.io/posts/linux_rootkits_03/)!
+
 Similar to [Section 3.2](../3.2_kill_signalling/), we can abuse hooking `sys_kill` to trigger a function that gives root to any process that sends a `64` signal to a process (as before, signal `64` is normally unused).
 
 According to [credentials.rst](https://github.com/torvalds/linux/blob/master/Documentation/security/credentials.rst#altering-credentials), we can only modify the `cred` struct of our own process, and not that of any other process. This means that we can't give an already running process root privileges unless we send the `64` signal from that process! Quite a clever security feature!