Skip to content
Chrome extension to inspect and find domains that don't resolve or have expired
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.

This is a chrome extension which inspects and find domains that don't resolve. This is primarily to help detect Second Order Subdomain Takeover. A second order subdomain takeover is when you're able to register a domain (expired, typoed, etc.) which are being referenced by some pages on some other domains. This may allow full or parital control over the page where the resource is being included/referenced.

These are some resources on the very topic:

And these are some relevant tools:


  1. Clone this repository
$ git clone
  1. Open chrome's extension page i.e. chrome://extensions
  2. Enable Developer mode (slider on the top-right)
  3. Click "Load upacked" and select the directory


  • Send email notification **
  • Get publicsuffix list from cache, if possible (doesn't seem necessary)
  • Avoid intercepting already scanned domains, if possible (doesn't seem necessary)
  • Check response to determine if the requested domain is parked (need more data)
  • Check for 1st order subdomain hijacking from domains listed in can-i-takeover-xyz (usefulness??)
  • Add persistent notification or whatever ** (Stacked notifications, clicking opens all previously discovered results)
You can’t perform that action at this time.