HackerOne: Lack of input sanitization in Marketo form leads to execution of HTML in lead emails

ID H1:220009
Type hackerone
Reporter encrypt
Modified 2017-10-03T17:35:47


Hi, There is SSRF vulnerability due to img tag injection in "Contact HackerOne Sales" form. Since vulnerability triggers after 18-20 minutes so I am not sure which site it affects. It might affect hackerone or marketo. So I thought it would be better to report it first on hackerone.


  1. Navigate to https://www.hackerone.com/product/features.
  2. Click on "Get Started".
  3. Fill FirstName, LastName, Company and Message by <img src=https://yourserver.com/f onerror=alert(1)>, <img src=https://yourserver.com/l onerror=alert(1)>, <img src=https://yourserver.com/c onerror=alert(1)> and <img src=https://yourserver.com/m onerror=alert(1)>.
  4. Fill the remaining details and submit the form.
  5. Wait 18-20 minutes and check server logs.

In this case ssrf triggers many times. Please check the screenshots.