I generated 16 character (upper/lower) subdomain and set up a virtual host for it in Apache, and within an hour was seeing vulnerability scans.

How are folks digging this up? What’s the strategy to avoid this?

I am serving it all with a single wildcard SSL cert, if that’s relevant.

Thanks

Edit:

  • I am using a single wildcard cert, with no subdomains attached/embedded/however those work
  • I don’t have any subdomains registered with DNS.
  • I attempted dig axfr example.com @ns1.example.com returned zone transfer DENIED

Edit 2: I’m left wondering, is there an apache endpoint that returns all configured virtual hosts?

Edit 3: I’m going to go through this hardening guide and try against with a new random subdomain https://www.tecmint.com/apache-security-tips/

  • Keelhaul@sh.itjust.worksEnglish
    4·
    20 hours ago

    Have you also tried making a subdomain and not making any requests to it yourself? So no browser access or other DNS resolution requests for the new subdomain. That should rule out some of the other possible causes suggested in the other comments.

    • Morphit @feddit.ukEnglish
      1·
      4 hours ago

      Dang, it could be the upstream DNS server passing along client queries. Maybe the ISP?

      In that case not even curl would be safe unless you could ensure all queries only resolve on your gear. Either use a host file entry or local DNS server.