> For the complete documentation index, see [llms.txt](https://utkarsh24122.gitbook.io/findings/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://utkarsh24122.gitbook.io/findings/oauth-misconfiguration.md).

# OAuth Misconfiguration

Modern Web And Android Apps use OAuth for easy authentication. I won't go into what it is and how it works because I have already shared the related learning resources in my Linkedin post : [Click here](https://www.linkedin.com/posts/utkarsh24122_websecurity-bugbounty-bugs-activity-6799341722955522048-IsvA) !

I have found various typical cases such as "missing state parameter" , "improper redirect\_uri validation" and others that one can learn from Portswigger's Web Security Academy <https://portswigger.net/web-security/oauth>. So I won't discuss those here.

Rather I will show how I found a logical flaw in the web app's OAuth implementation which is not described in Portswigger's article.

One of the public programs on Bugcrowd was using google OAuth. I tested the basic test cases but the functionality was quite well implemented.

However I noticed that immediate 'Email verification was not required to create an account.

I am putting the screenshots from the report so that I dont have to explain the impact here again 🤪.

![Description](/files/-MhrGZDw-JgRD8OVTUIG)

![Impact](/files/-MhrQUFQegkGcLhlKoyR)

I did some more research about this and found this amazing blog by [@harshbothra\_](https://twitter.com/harshbothra_) :\
<https://hbothra22.medium.com/attacking-social-logins-pre-authentication-account-takeover-790248cfdc3>\
&#x20;


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://utkarsh24122.gitbook.io/findings/oauth-misconfiguration.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.