A dangling DNS record is a CNAME record that points to a resource which no longer exists. A dangling DNS record can be exploited in what is known as subdomain takeover.

Let’s say we have a CNAME record which points to example.azurewebsites.net. example.azurewebsites.net is our Azure App Service instance. We no longer need our App Service instance, so we delete it, and in doing so our domain name example.azurewebsites.net is also deleted.

Our CNAME record is still pointing to example.azurewebsites.net so we should delete our CNAME record too. If we forget to delete our CNAME record, which sometimes happens, we…


Put simply, a blockchain is a distributed database, which stores records of values and transactions. Almost anything can be recorded on the blockchain. Most transactions would normally require some sort of intermediary to provide trust, security, and to facilitate the transactions. An intermediary is a person or organisation who acts as a link between two parties (i.e. banks, financial institutions etc.). Blockchain technology removes the need for an intermediary, allowing people to transact directly with each other. Bitcoin is probably the most well known blockchain-based system.

A library holds the central database of all their books. There’s a particular book…

James Borwick

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