Book Image

Android Security Cookbook

Book Image

Android Security Cookbook

Overview of this book

Android Security Cookbook discusses many common vulnerabilities and security related shortcomings in Android applications and operating systems. The book breaks down and enumerates the processes used to exploit and remediate these vulnerabilities in the form of detailed recipes and walkthroughs. The book also teaches readers to use an Android Security Assessment Framework called Drozer and how to develop plugins to customize the framework. Other topics covered include how to reverse-engineer Android applications to find common vulnerabilities, and how to find common memory corruption vulnerabilities on ARM devices. In terms of application protection this book will show various hardening techniques to protect application components, the data stored, secure networking. In summary, Android Security Cookbook provides a practical analysis into many areas of Android application and operating system security and gives the reader the required skills to analyze the security of their Android devices.
Table of Contents (16 chapters)
Android Security Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Application signature verification (anti-tamper)


One of the cornerstones of Android security is that all apps must be digitally signed. Application developers sign apps using a private key in the form of a certificate. There's no need to use a certificate authority, and in fact, it's more common to use self-signed certificates.

Certificates are usually defined with an expiration date, and the Google Play store requires a validity period ending after October 22, 2033. This highlights the fact that our app signing key stays consistent throughout the life of the app. One of the primary reasons is to protect and prevent app upgrades unless the signatures of the old and upgraded .apk files are identical.

So, if this verification already happens, why add a check for signature consistency?

Part of the process of an attacker modifying your application's .apk file breaks the digital signature. This means that, if they want to install the .apk file on an Android device, it will need to be resigned using...