MajesticSEO is a tool that is as well-known as it is respected. It is great for site audits and research, but it also has an important use in the current state of SEO where it has become clear that your site can be hurt externally, through bad links.
MajesticSEO can help you diagnose bad links, and possibly a bad linking campaign. Though, it is entirely possible the bad links dragging you down are not coming from external sources, but instead are caused by unscrupulous site owners or SEOs.
Search Engine Journal writer Irish Wonder helps walk you through identifying and understanding bad links with the use of this great SEO tool. They aren’t perfect means of diagnosing your problem, but they can help point you in the right direction if you can’t pinpoint the exact issue.