I wrote an article about this and at the time I was very unhappy with Google, because many innocent people and websites were being unfairly penalized by Google.
Also all the Google penalties back then was causing the Negative SEO market to grow fast. Luckily Google decided to slow down and be more careful about giving out penalties which in turn lowered the desire and demand for people to try Negative SEO. It can be done and I could do it Google, the only thing that stops me are my morals. Please keep that in mind, and understand there are Black Hat SEO experts that know exactly how to perform negative SEO. I have personally seen and suffered from their work and Google could not stop them and Google did not help. I have even sent in examples of Negative SEO to Senior Google management several years ago, because some evil person did Negative SEO successfully to one of my websites. I understand Google needs to keep people clam, yet I need to explain the truth to people.There are several different ways to perform Negative SEO, not just from low quality backlinks. The people that did it to me were in Canada, so that made it even more difficult to stop them. Basically the Black Hat SEO's won and I lost. I am still unhappy that I could not defeat the evil doers, I really hate losing to them!