Book Image

Learning Linux Binary Analysis

By : Ryan "elfmaster" O'Neill
5 (1)
Book Image

Learning Linux Binary Analysis

5 (1)
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

The PT_NOTE to PT_LOAD conversion infection method


This method is extremely powerful and, although easily detectable, is also relatively easy to implement and provides reliable code insertion. The idea is to convert the PT_NOTE segment to the PT_LOAD type and move its position to go after all of the other segments. Of course, you could also just create an entirely new segment by creating a PT_LOAD phdr entry, but since a program will still execute without a PT_NOTE segment, you might as well convert it to PT_LOAD. I have not personally implemented this technique for a virus, but I have designed a feature in Quenya v0.1 that allows you to add a new segment. I also did an analysis of the Retaliation Linux virus authored by Jpanic, which uses this method for infection:

http://www.bitlackeys.org/#retaliation.

Figure 4.5: PT_LOAD infection

There are no strict rules about the PT_LOAD infection. As mentioned here, you may convert PT_NOTE into PT_LOAD or create an entirely new PT_LOAD phdr and segment...