Trackback Spammers Are Getting Smarter

The trackback spammers are getting clever it seems. Tonight 5 spams got through for the first time in months.

My antispam system visits the URL submitted on the site to see if they link back to me. If they do, they are probably genuine so get let through. If they don't they are flagged as suspicious and if an IP address is flagged more than 3 times anything from there is classed as spam.

The spammers have actually done something quite clever. When I request the page to check, they detect my IP address and they match it to any domain they have in their database and append the domain name as dummy links under the closing html </html> tag. So when I try to check from the server hosting robertprice.co.uk it appends robertprice.co.uk links to the page, when I check from another, it gives the real page minus the links.

The new solution is to detect these bogus links as they are invalid html and treat them as spam.

Ideally I should be using something like Akismet, but that's not as much fun. :-)