Subdomain Takeover in Interactsh server

A domain configured with interactsh server was vulnerable to subdomain takeover for specfic subdomain, i.e app, Interactsh server before < 1.0.0 used to create cname entries for app pointing to projectdiscovery.github.io as default which intended to used for hosting interactsh web client using GitHub pages. It turns out to be a security issue with a self-hosted interactsh server in which the user may not have configured a web client but still have a cname entry pointing to GitHub pages, making them vulnerable to subdomain takeover.

This issue was initially reported to us as a subdomain takeover for one of our domains that runs interactsh server by Melih at [email protected], and after conducting an internal investigation, we determined that it was an issue with the default config of interactsh server affecting all the server running self-hosted instance of interactsh, as a result - cname entry has been removed in the latest release.

Impact

This allows one to host / run arbitrary client side code (XSS) in a user's browser when browsing the vulnerable subdomain, for more details on the impact, please read this detailed blogpost from Detectify.

Patches

Update to Interactsh server v1.0.0 with go install -v github.com/projectdiscovery/interactsh/cmd/interactsh-server@latest

References

https://github.com/projectdiscovery/interactsh/issues/136

For more information

If you have any questions or comments about this advisory:

• Email us at [email protected]