Negative SEO

How does Google know you didn't buy last weeks WSO blast-o-matic link package for $7?

You can bet they're harvesting data but I seriously doubt it's for making friends with webmasters.

Is fiverr in your web history?

I doubt you would be able to find the "source" of the negative seo attack. Maybe it's competition? In regards to using the disavow tool.... There are mixed feelings about it. Either use the tool or do a redirect to a new domain.

I'd count yourself lucky, that all your getting hit with are some spammy links. Linkspam is probably bottom of my list when it comes to Neg-SEO. 99% of the time it doesn't work, because 99% of the fools doing it, don't know how to do it properly. It's the same people that where trying to rank with it unsuccessfully 2 years ago. You need to know how to rank a page with spam, before you could ever know how to tank a page with spam.

I could think of a dozen far more immediate and effective ways to perform Neg-SEO, none of which I would be willing to discuss here. But in short, Neg-SEO existed long before linkspam was ever included into the frame. A marginal addition to a long list of applicable negative acts that could be performed, is all it really is. It's just a lot more accessible and less intuitive weapon available.

An existing strong link profile can mitigate against a linkspam attack, so that discounts the vast majority of affiliate and small business sites from surviving. The bad news is however, that linkspam Neg is a 0 numbers game. The more instances of it occurring the more popular it will become.

It suits the current group of large Corpa sites who dominate most of the current commercial SERPs also. As they have the power to almost ignore linkspam attacks, while new start-ups entering the market have their necks stood on every time they hit page 1 for a keyword. And when the would be attackers take their place, they will be hit. And on the circle will go to infinity. All the while, the already established authority sites will just keep growing exponentially in strength.

Give them guns, and watch them kill each other. Google is laughing.

The only way to combat negative SEO is via link removals. Disavow tool doesn't work.