Host Header Poisoning in thisdata.com

Summary

ThisData made inappropriate use of the user-supplied host header, which could have resulted in a user being redirected to an arbitrary domain under some circumstances. On other pages, the header was used within metadata values like the canonical URL.

7H0R4PP4N was very thorough and helpful as we resolved this issue!

The application appears to trust the user-supplied host header. The user is redirected to any domain as set in host header. In certain pages like /signup or the homepage itself, the header is used to build links within the page rather than redirecting the user. This could also be used for cache poisoning attacks.