I operate a simple lead-generation website for a friend, consisting of a single page with an HTML form with just one field: email address.
We are getting an unexpected number of POSTs to the form's action URL.
Each one has a different, and apparently genuine, email address, but we are getting way more than we would expect for our little website.
What possible malicious purpose could these POSTs have? We have never sent email to any of the addresses submitted, yet the POSTs continue.
There is nothing else in the POST request. Nothing else in the body, nothing added to the URL, no query parameters, nothing that looks like SQL injection attempts, no unique IDs to identify the request, no garbage, nothing.
The rate is less than a hundred a day. Nothing that could suggest a DOS attempt.
The source IPs are different, but the User Agent strings are always the same, which suggests the requests are coming from a bot or a script.
It all seems pretty harmless, but I'm curious what the purpose could be in abusing our form like this?