Buy a Burp Suite Certified Practitioner exam, pass before 15 Dec, and we'll refund your $99.  –   Find out more
  1. Web Security Academy
  2. Cross-site scripting
  3. Contexts
  4. Lab

Lab: Reflected XSS in a JavaScript URL with some characters blocked

EXPERT

This lab reflects your input in a JavaScript URL, but all is not as it seems. This initially seems like a trivial challenge; however, the application is blocking some characters in an attempt to prevent XSS attacks.

To solve the lab, perform a cross-site scripting attack that calls the alert function with the string 1337 contained somewhere in the alert message.

Register for free to track your learning progress

The benefits of working through PortSwigger's Web Security Academy
  • Practise exploiting vulnerabilities on realistic targets.

  • Record your progression from Apprentice to Expert.

  • See where you rank in our Hall of Fame.

Already got an account? Login here