Book Image

Learning Linux Binary Analysis

By : Ryan "elfmaster" O'Neill
Book Image

Learning Linux Binary Analysis

By: Ryan "elfmaster" O'Neill

Overview of this book

Learning Linux Binary Analysis is packed with knowledge and code that will teach you the inner workings of the ELF format, and the methods used by hackers and security analysts for virus analysis, binary patching, software protection and more. This book will start by taking you through UNIX/Linux object utilities, and will move on to teaching you all about the ELF specimen. You will learn about process tracing, and will explore the different types of Linux and UNIX viruses, and how you can make use of ELF Virus Technology to deal with them. The latter half of the book discusses the usage of Kprobe instrumentation for kernel hacking, code patching, and debugging. You will discover how to detect and disinfect kernel-mode rootkits, and move on to analyze static code. Finally, you will be walked through complex userspace memory infection analysis. This book will lead you into territory that is uncharted even by some experts; right into the world of the computer hacker.
Table of Contents (17 chapters)
Learning Linux Binary Analysis
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Kprobe rootkits


This particular type of kernel rootkit was originally conceived and described in great detail in a 2010 Phrack paper that I wrote. The paper can be found at http://phrack.org/issues/67/6.html.

This type of kernel rootkit is one of the more exotic brands in that it uses the Linux kernels Kprobe debugging hooks to set breakpoints on the target kernel function that the rootkit is attempting to modify. This particular technique has its limitations, but it can be quite powerful and stealthy. However, just like any of the other techniques, if the analyst knows what to look for, then the kernel rootkits that use kprobes can be quite easy to detect.

Detecting kprobe rootkits

Detecting the presence of kprobes by analyzing memory is quite easy. When a regular kprobe is set, a breakpoint is placed on either the entry point of a function (see jprobes) or on an arbitrary instruction. This is extremely easy to detect by scanning the entire code segment looking for breakpoints, as there is...