> For the complete documentation index, see [llms.txt](https://www.webhackingtips.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.webhackingtips.com/week-40-jwt-testing.md). # Week 40 - JWT Testing Looking for a quick way to test JSON Web Tokens (JWT's) during an [#AppSec](https://www.linkedin.com/feed/hashtag/?keywords=appsec\&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A6988868624044191744) engagement?\ \ I highly recommend using jwt\_tool! To get it running, just locate a GET request to an authenticated endpoint that uses a JWT in the Authorization header. Then run the following command:\ \ `python3`[`jwt_tool.py`](http://jwt_tool.py) `-M at -t "https[:]//staging[.]client[.]com/api/v3/endpoint" -rh "Authorization: Bearer eyJ0eHAiCiJKV1QiLCJhbGciO…"`\ \ The -M option sets the attack mode; in the above case we set ‘at’ for all tests. The -t option is the target URL. The -rh allows us to specify request headers, in this case, the Authorization request header containing the JWT.\ \ Then let it rip! It will auto-magically test common exploits, claim fuzzing, token misconfigurations, etc. Leaving you more time for that Business Logic!\ \ Let me know what tools you use for [#JWT](https://www.linkedin.com/feed/hashtag/?keywords=jwt\&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A6988868624044191744) testing in the comments below. ![](/files/4G6tErWD2X2YxEvvA2fm) --- # 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://www.webhackingtips.com/week-40-jwt-testing.md?ask= ``` 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.