My client (white hat) has a ton of backlinks like this: backlink from randomwebsite.com with target URL = clientwebsite.com/redirect?url=pornwebsite.com My client is ranking well but there are about 5,000 of these links... how much harm are they causing? and what should be my course of action if they need to be removed? disavow?
If all the links are from the same domain you can disavow the entire domain and all links from it will be ignored. I've never been a fan of the disavow tool, but if there are a lot of spammy backlinks you don't recognize, it's worth considering to use it.
Seems like a nasty blast. Disavow those links as soon as possible before getting into serious trouble.