Web Hacking 101
Web Hacking 101
How to Make Money Hacking Ethically
About the Book
With a Foreword written by HackerOne Co-Founders Michiel Prins and Jobert Abma, Web Hacking 101 is about the ethical exploration of software for security issues but learning to hack isn't always easy. With few exceptions, existing books are overly technical, only dedicate a single chapter to website vulnerabilies or don't include any real world examples. This book is different.
Using publicly disclosed vulnerabilities, Web Hacking 101 explains common web vulnerabilities and will show you how to start finding vulnerabilities and collecting bounties. With over 30 examples, the book covers topics like:
- HTML Injection
- Cross site scripting (XSS)
- Cross site request forgery (CSRF)
- Open Redirects
- Remote Code Execution (RCE)
- Application Logic
- and more...
Each example includes a classification of the attack, a report link, the bounty paid, easy to understand description and key takeaways. After reading this book, your eyes will be opened to the wide array of vulnerabilities that exist and you'll likely never look at a website or API the same way.
Reader Testimonials

Danil Gribkov
@danilgribkov
I highly recommend Web Hacking 101. The $10 I paid was more than worth it when I got a $500 bounty from PayPal using examples Pete provided. Combined with the constant updates he provides, which I have access to for life, it's a great buy.

Jason Haddix
Father, hacker, Director of Technical Operations @Bugcrowd, blogger, & nerd
I support Bounty Hunters, #reading Web Hacking 101: How to Make Money Hacking Ethically by @yaworsk #bugbounty - leanpub.com/web-hacking-101 --Twitter

Michiel Prins
Co-Found of HackerOne
Want to explore the art and skill of hacking? Try the latest release of @yaworsk's book! --Twitter

Jobert Abma
Co-Founder of HackerOne
Anyone who's interested in web hacking and making money with it, I'd recommend reading this book: leanpub.com/web-hacking-101! #bugbounty --Twitter

Leo Niemelä
CSO at LocalTapiola Group
Worth to read (just bought my copy): How to Make Money Hacking Ethically by @yaworsk leanpub.com/web-hacking-101 #bugbounty --Twitter

Ben Sadeghipour
Bug Bounty participant. Blogger. Gamer.
Awesome book written by @yaworsk. If for some reason you haven't read it yet make sure you do! --Twitter

Jonathan Avery
Hacker
Real-world case studies that helped me score a $600 "Hack The Pentagon" bounty. This book also gave me the confidence boost I needed to land a high paying job as a security engineer at a top aerospace defense company.

@brutelogic
Security researcher @sucurisecurity
Superb work by @yaworsk in leanpub.com/web-hacking-101 I couldn't recommend it more, awesome writing style, you definitely should get it! --Twitter

Ebrietas
Pseudo hacker, information security lover, and bug bounty participant
Web hacking 101 is an amazing beginners guide to breaking web applications as a bug bounty hunter. All sections of the book are backed up by references from actual publicly disclosed vulnerabilities. The focus on the unique findings for each category will more than likely teach some new tricks. It is well worth double the asking price.

Andy Grunwald
Software Engineer (Site Reliability and Platform Engineering) at @trivago. I solve problems and put things into production.
I recommend "Web Hacking 101" about bug bounties and web security. Great book. Thank you @yaworsk leanpub.com/web-hacking-101 #bugbounty --Twitter
Table of Contents
- 1. Foreword
-
2. Introduction
-
- How It All Started
- Just 30 Examples and My First Sale
- Who This Book Is Written For
- Chapter Overview
- Word of Warning and a Favour
-
- 3. Background
-
4. Open Redirect Vulnerabilities
- Description
-
Examples
- 1. Shopify Theme Install Open Redirect
- 2. Shopify Login Open Redirect
- 3. HackerOne Interstitial Redirect
- Summary
-
5. HTTP Parameter Pollution
- Description
-
Examples
- 1. HackerOne Social Sharing Buttons
- 2. Twitter Unsubscribe Notifications
- 3. Twitter Web Intents
- Summary
-
6. Cross-Site Request Forgery
- Description
-
Examples
- 1. Shopify Twitter Disconnect
- 2. Change Users Instacart Zones
- 3. Badoo Full Account Takeover
- Summary
-
7. HTML Injection
- Description
-
Examples
- 1. Coinbase Comments
- 2. HackerOne Unintended HTML Inclusion
- 3. Within Security Content Spoofing
- Summary
-
8. CRLF Injection
-
Description
- 1. Twitter HTTP Response Splitting
- 2. v.shopify.com Response Splitting
- Summary
-
Description
-
9. Cross-Site Scripting
- Description
-
Examples
- 1. Shopify Wholesale
- 2. Shopify Giftcard Cart
- 3. Shopify Currency Formatting
- 4. Yahoo Mail Stored XSS
- 5. Google Image Search
- 6. Google Tagmanager Stored XSS
- 7. United Airlines XSS
- Summary
-
10. Template Injection
-
Description
- Server Side Template Injections
- Client Side Template Injections
-
Examples
- 1. Uber Angular Template Injection
- 2. Uber Template Injection
- 3. Rails Dynamic Render
- Summary
-
Description
-
11. SQL Injection
-
Description
- SQL Databases
- Countermeasures Against SQLi
-
Examples
- 1. Drupal SQL Injection
- 2. Yahoo Sports Blind SQL
- 3. Uber Blind SQLi
- Summary
-
Description
-
12. Server Side Request Forgery
-
Description
- HTTP Request Location
- Invoking GET Versus POST Requests
- Blind SSRFs
- Leveraging SSRF
-
Examples
- 1. ESEA SSRF and Querying AWS Metadata
- 2. Google Internal DNS SSRF
- 3. Internal Port Scanning
- Summary
-
Description
-
13. XML External Entity Vulnerability
- Description
-
Examples
- 1. Read Access to Google
- 2. Facebook XXE with Word
- 3. Wikiloc XXE
- Summary
-
14. Remote Code Execution
- Description
-
Examples
- 1. Polyvore ImageMagick
- 2. Algolia RCE on facebooksearch.algolia.com
- 3. Foobar Smarty Template Injection RCE
- Summary
-
15. Memory
-
Description
- Buffer Overflow
- Read out of Bounds
- Memory Corruption
-
Examples
- 1. PHP ftp_genlist()
- 2. Python Hotshot Module
- 3. Libcurl Read Out of Bounds
- 4. PHP Memory Corruption
- Summary
-
Description
-
16. Sub Domain Takeover
- Description
-
Examples
- 1. Ubiquiti Sub Domain Takeover
- 2. Scan.me Pointing to Zendesk
- 3. Shopify Windsor Sub Domain Takeover
- 4. Snapchat Fastly Takeover
- 5. api.legalrobot.com
- 6. Uber SendGrid Mail Takeover
- Summary
-
17. Race Conditions
- Description
-
Examples
- 1. Starbucks Race Conditions
- 2. Accepting HackerOne Invites Multiple Times
- 3. Exceeding Keybase Invitation Limits
- 4. HackerOne Payments
- Summary
-
18. Insecure Direct Object References
- Description
-
Examples
- 1. Binary.com Privilege Escalation
- 2. Moneybird App Creation
- 3. Twitter Mopub API Token Stealing
- Summary
-
19. OAuth
- Description
-
Examples
- 1. Swiping Facebook Official Access Tokens
- 2. Stealing Slack OAuth Tokens
- 3. Stealing Google Drive Spreadsheets
- Summary
-
20. Application Logic Vulnerabilities
- Description
-
Examples
- 1. Shopify Administrator Privilege Bypass
- 2. HackerOne Signal Manipulation
- 3. Shopify S3 Buckets Open
- 4. HackerOne S3 Buckets Open
- 5. Bypassing GitLab Two Factor Authentication
- 6. Yahoo PHP Info Disclosure
- 7. HackerOne Hacktivity Voting
- 8. Accessing PornHub’s Memcache Installation
- 9. Bypassing Twitter Account Protections
- Summary
-
21. Getting Started
-
Reconnaissance
- Subdomain Enumeration
- Port Scanning
- Screenshotting
- Content Discovery
- Previous Bugs
-
Testing the Application
- The Technology Stack
- Functionality Mapping
- Finding Vulnerabilities
- Going Further
- Summary
-
Reconnaissance
-
22. Vulnerability Reports
- Read the disclosure guidelines.
- Include Details. Then Include More.
- Confirm the Vulnerability
- Show Respect for the Company
- Bounties
- Don’t Shout Hello Before Crossing the Pond
- Parting Words
-
23. Tools
- Burp Suite
- ZAP Proxy
- Knockpy
- HostileSubBruteforcer
- Sublist3r
- crt.sh
- IPV4info.com
- SecLists
- XSSHunter
- sqlmap
- Nmap
- Eyewitness
- Gowitness
- Gobuster
- Meg
- Shodan
- Censys
- What CMS
- BuiltWith
- Nikto
- Recon-ng
- GitRob
- CyberChef
- OnlineHashCrack.com
- idb
- Wireshark
- Bucket Finder
- Race the Web
- Google Dorks
- JD GUI
- Mobile Security Framework
- Ysoserial
-
Firefox Plugins
- FoxyProxy
- User Agent Switcher
- Firebug
- Hackbar
- Websecurify
- Cookie Manager+
- XSS Me
- Offsec Exploit-db Search
- Wappalyzer
-
24. Resources
-
Online Training
- Web Application Exploits and Defenses
- The Exploit Database
- Udacity
-
Bug Bounty Platforms
- Hackerone.com
- Bugcrowd.com
- Synack.com
- Cobalt.io
- Video Tutorials
- youtube.com/yaworsk1
- Seccasts.com
- How to Shot Web
-
Further Reading
- OWASP.com
- Hackerone.com/hacktivity
- https://bugzilla.mozilla.org
- Twitter #infosec and #bugbounty
- Twitter @disclosedh1
- Web Application Hackers Handbook
- Bug Hunters Methodology
-
Recommended Blogs
- philippeharewood.com
- Philippe’s Facebook Page - www.facebook.com/phwd-113702895386410
- fin1te.net
- NahamSec.com
- blog.it-securityguard.com
- blog.innerht.ml
- blog.orange.tw
- Portswigger Blog
- Nvisium Blog
- blog.zsec.uk
- brutelogic.com.br
- lcamtuf.blogspot.ca
- Bug Crowd Blog
- HackerOne Blog
- Cheatsheets
-
Online Training
-
25. Glossary
-
- Black Hat Hacker
- Buffer Overflow
- Bug Bounty Program
- Bug Report
- CRLF Injection
- Cross Site Request Forgery
- Cross Site Scripting
- HTML Injection
- HTTP Parameter Pollution
- HTTP Response Splitting
- Memory Corruption
- Open Redirect
- Penetration Testing
- Researchers
- Response Team
- Responsible Disclosure
- Vulnerability
- Vulnerability Coordination
- Vulnerability Disclosure
- White Hat Hacker
-
-
26. Appendix A - Take Aways
- Open Redirects
- HTTP Parameter Pollution
- Cross Site Request Forgery
- HTML Injection
- CRLF Injections
- Cross-Site Scripting
- SSTI
- SQL Injection
- Server Side Request Forgery
- XML External Entity Vulnerability
- Remote Code Execution
- Memory
- Sub Domain Takeover
- Race Conditions
- Insecure Direct Object References
- OAuth
- Application Logic Vulnerabilities
- 27. Appendix B - Web Hacking 101 Changelog
Authors have earned$9,893,383writing, publishing and selling on Leanpub, earning 80% royalties while saving up to 25 million pounds of CO2 and up to 46,000 trees.
Learn more about writing on Leanpub
The Leanpub 45-day 100% Happiness Guarantee
Within 45 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers), EPUB (for phones and tablets) and MOBI (for Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.
Learn more about Leanpub's ebook formats and where to read them
Top Books
C++ Best Practices
Jason TurnerLevel up your C++, get the tools working for you, eliminate common problems, and move on to more exciting things!
OpenIntro Statistics
David Diez, Christopher Barr, Mine Cetinkaya-Rundel, and OpenIntroA complete foundation for Statistics, also serving as a foundation for Data Science.
Leanpub revenue supports OpenIntro (US-based nonprofit) so we can provide free desk copies to teachers interested in using OpenIntro Statistics in the classroom and expand the project to support free textbooks in other subjects.
More resources: openintro.org.
Functional Design and Architecture
Alexander GraninSoftware Design in Functional Programming, Design Patterns and Practices, Methodologies and Application Architectures. How to build real software in Haskell with less efforts and low risks. The first complete source of knowledge.
Atomic Kotlin
Bruce Eckel and Svetlana IsakovaFor both beginning and experienced programmers! From the author of the multi-award-winning Thinking in C++ and Thinking in Java together with a member of the Kotlin language team comes a book that breaks the concepts into small, easy-to-digest "atoms," along with exercises supported by hints and solutions directly inside IntelliJ IDEA!
C++20
Rainer GrimmC++20 is the next big C++ standard after C++11. As C++11 did it, C++20 changes the way we program modern C++. This change is, in particular, due to the big four of C++20: ranges, coroutines, concepts, and modules.
The book is almost daily updated. These incremental updates ease my interaction with the proofreaders.
Introductory Statistics with Randomization and Simulation
Mine Cetinkaya-Rundel, Christopher Barr, OpenIntro, and David DiezA complete foundation for Statistics, also serving as a foundation for Data Science, that introduces inference using randomization and simulation while covering traditional methods.
Leanpub revenue supports OpenIntro, so we can provide free desk copies to teachers interested in using our books in the classroom.
More resources: openintro.org.
Java OOP Done Right
Alan MellorObject Oriented Programming is still a great way to create clean, maintainable code. But only if you use it right.
This book gives you 25 years of OO best practice, ready to use.
You'll learn to design objects behaviour-first, use TDD to help, then confidently apply Design Patterns, SOLID principles and Refactoring to make clean, crafted code.
Ansible for DevOps
Jeff GeerlingAnsible is a simple, but powerful, server and configuration management tool. Learn to use Ansible effectively, whether you manage one server—or thousands.
Composing Software
Eric ElliottAll software design is composition: the act of breaking complex problems down into smaller problems and composing those solutions. Most developers have a limited understanding of compositional techniques. It's time for that to change.
Cloud Strategy
Gregor Hohpe“Strategy is the difference between making a wish and making it come true.” A successful migration to the cloud shouldn’t be driven by wishes, but guided by a sound strategy, frameworks, and decision models. This book tells you how—without becoming superficial nor getting lost in technology and product details.
Top Bundles
- #1
Software Architecture for Developers: Volumes 1 & 2 - Technical leadership and communication
2 Books
"Software Architecture for Developers" is a practical and pragmatic guide to modern, lightweight software architecture, specifically aimed at developers. You'll learn:The essence of software architecture.Why the software architecture role should include coding, coaching and collaboration.The things that you really need to think about before... - #2
CCIE Service Provider Ultimate Study Bundle
2 Books
Piotr Jablonski, Lukasz Bromirski, and Nick Russo have joined forces to deliver the only CCIE Service Provider training resource you'll ever need. This bundle contains a detailed and challenging collection of workbook labs, plus an extensively detailed technical reference guide. All of us have earned the CCIE Service Provider certification... - #3
Cisco CCNA 200-301 Complet
4 Books
Ce lot comprend les quatre volumes du guide préparation à l'examen de certification Cisco CCNA 200-301. - #4
CCDE Practical Studies (All labs)
3 Books
CCDE lab - #5
Modern Management Made Easy
3 Books
Read all three Modern Management Made Easy books. Learn to manage yourself, lead and serve others, and lead the organization. - #6
The Future of Digital Health
6 Books
We put together the most popular books from The Medical Futurist to provide a clear picture about the major trends shaping the future of medicine and healthcare. Digital health technologies, artificial intelligence, the future of 20 medical specialties, big pharma, data privacy and how technology giants such as Amazon or Google want to conquer... - #7
Modern C++ by Nicolai Josuttis
2 Books
- #8
Django for Beginners/APIs/Professionals
3 Books
- #9
"The C++ Standard Library" and "Concurrency with Modern C++"
2 Books
Get my books "The C++ Standard Library" and "Concurrency with Modern C++" in a bundle. The first book gives you the details you should know about the C++ standard library; the second one dives deeper into concurrency with modern C++. In sum, you get more than 600 pages full of modern C++ and about 250 source files presenting the standard library... - #10
Linux Administration Complet
4 Books
Ce lot comprend les quatre volumes du Guide Linux Administration :Linux Administration, Volume 1, Administration fondamentale : Guide pratique de préparation aux examens de certification LPIC 1, Linux Essentials, RHCSA et LFCS. Administration fondamentale. Introduction à Linux. Le Shell. Traitement du texte. Arborescence de fichiers. Sécurité...