HI Viki,
Absolutely, as you keep maintaining the application you see what visitors are trying to achieve. The more they try, the better your analysis is. The better results you achieve.
You can use standard Apache rewrite rules to kick out any unwanted visitors, here I'm showing forbidden.
RewriteRule ^content/xyz/example/[^/]+/https://example.com$ - [F]
Or it can come up as a more complicated rule that attempt to block all the cases:
RewriteRule ^content/xyz/example/[^/]+(?!mailto:)(?:(?:http|https|ftp)://)(?:\\S+(?::\\S*)?@)?(?:(?:(?:[1-9]\\d?|1\\d\\d|2[01]\\d|22[0-3])(?:\\.(?:1?\\d{1,2}|2[0-4]\\d|25[0-5])){2}(?:\\.(?:[0-9]\\d?|1\\d\\d|2[0-4]\\d|25[0-4]))|(?:(?:[a-z\\u00a1-\\uffff0-9]+-?)*[a-z\\u00a1-\\uffff0-9]+)(?:\\.(?:[a-z\\u00a1-\\uffff0-9]+-?)*[a-z\\u00a1-\\uffff0-9]+)*(?:\\.(?:[a-z\\u00a1-\\uffff]{2,})))|localhost)(?::\\d{2,5})?(?:(/|\\?|#)[^\\s]*)?$ - [F]
However, no matter how hard you try the user will still win and unwanted requests will reach Publisher, if someone really tries.
Regards,
Peter