Tags: Medium WebExploitation picoCTF2023

  1. Launch the instance
  2. Open the URL
  3. On inspecting the source code, we can see that the input text of the form is being validated by fetch() with a get request to the /flag endpoint.
  4. Not really a regex match but we’ll try matching the known first characters of a flag, i.e. picoCTF. And it works!