same-origin-xss - Same Origin XSS challenge

项目说明

soXSS - writeup

Introduction

The challenge consisted of two components:
1. Text input for HTML notes.
2. Rendered HTML page from textarea, rendered inside an iframe.

The embedded iframe was within the same origin, but data sent to it was sanitized by DOMPurify.

The idea

The idea for the challenge was rather simple:
1. Bypass the below snippet included inside iframe.

2. Steal the identifier.
3. Steal the saved note from the main page with a valid identifier.

*💡 The name of the challenge - soXSS - was referring to Same-Origin XSS.*

The solution

One could notice that the identifier was stored in a user's session and the session cookie was set to Lax. To solve the challenge the intended way was to bypass the following check e.origin !== window.origin. When //example.org is embeded into a sandboxed iframe, then the page's origin will be null, i.e. window.origin === 'null'. So just by embedding the iframe via <iframe sandbox="allow-scripts" src=" we could force the null origin, only if the page was embeddable and cookies set to SameSite=None, but it wasn't the case for the challenge. The lesser known fact is that when the sandbox value allow-popups is set then the opened popup will inherit all the sandboxed attributes unless allow-popups-to-escape-sandbox is set. And that is the solution to the challenge:
1. From a sandboxed page open a popup to .
2. From any other null origin send a simple XSS to the popup and steal the identifier.
3. Open and send XSS with stolen identifier so the origin is so-xss.terjanq.me.

All the steps are included in the below simple PoC:

Credits

项目信息

开发语言：HTML

Star 数：64

技术要点

该项目属于CTF思路方向的开源资源，代码结构清晰，适合安全研究人员学习参考。项目围绕Same Origin XSS challenge展开，提供了可运行的实现，对理解相关安全机制、工具原理与攻防技术具有较高的研究价值。

从技术实现角度看，此类项目的核心在于对底层原理的深入理解与工程化落地。开发者在研究过程中可以结合官方文档与社区讨论，梳理项目的初始化流程、核心模块职责与数据流转，逐步掌握其中的技术细节与设计思路。

使用与学习建议

1. 下载源码压缩包，解压到本地环境。

2. 根据项目类型准备对应的运行环境与依赖。

3. 按照 README 中的步骤完成配置与部署。

4. 在隔离的测试环境中运行验证，避免影响生产系统。

免责声明

本资源来源于开源社区，仅供安全研究、技术学习与合法授权范围内的攻防演练使用，请勿用于任何非法或侵害他人权益的用途。使用本项目产生的一切后果由使用者自行承担。