How to prevent people spamming out.php with their malicious links?
Is there some checksum system or something to prevent this issue in the future?
Google has detected a significant portion of your site being abused with spam that violates Google's Webmaster Guidelines and adds little or no value to the web. The spammy content may appear in your forums, guestbooks, social media platforms, file uploader, free hosting services, or internal search pages.
This spammy content is possibly generated by site users or other third-parties, and it leverages your site to promote spam rather than the actual subject matter of your site.
Therefore, a manual spam action has been applied to appropriate URLs matching this pattern: domain.com/out.php?p=100&link=main&url=
Following are some example URLs where we found pages that have been compromised. Please review them to gain a better sense of where these spammy content appears. Please note that the list is not exhaustive.
URL: https://domain.com/out.php?p=100&link=m ... mainDXG651