alt Hacker NewsI'd advocate for actually believing the HTTPD in this case. In the main, if it says '403 Forbidden', then it is forbidden. If it says '200 OK', then it is ok.
I would argue that the web server's reply counts as a communication. The argument "but we didn't intend to grant access" goes so far, because what other information do I base myself on to guess that you didn't?
Roughly speaking, that is. Because, despite the fact that this would appear to be a straightforward uncontested and literal communication logged and timestamped by both sides and their respective server and user agents; lawyers somehow fall back to analogies instead.
If I repeat my credit card number example above:
Assume that an attacker generates a random credit number and attempts to make a purchase online. VISA honours the number and processes the payment. Is the attacker not guilty because VISA's server didn't return a 403 Forbidden (or 401)?
When you download a file from a public S3 bucket, for example, you get a signed URL that expires after a certain date. If someone guesses the signature and downloads the file, are they not guilty because the web server did not return a 200?
If someone guesses your password and reads your mail, is it ok because the IMAP server did not return an error?