Negative SEO refers to the placement of "bad links", content theft, the use of fake profiles on social networks and website hacking. These "black" methods are used to displace a competitor's resource from its positions for the purposes of commercial espionage. The affected site faces manual sanctions or an automatic filter.
Bad links refer to those that lead to pornographic sites, gambling sites, doorways, and non-thematic resources. They may appear on the site as a result of automatic purchase of links from link exchanges, or someone places them manually.
No less common is the theft of content before the page with it has been indexed by a search engine. This is done through an RSS feed or parsing. In the event that the plagiarist resource is older and more authoritative, authorship will be automatically assigned to it. And its owners will even be able to complain to Google about the true original source.

Malicious promotion specialists can also delete high-quality and useful links. To do this, they contact webmasters of donor sites and refer to copyright law. When faced with such a request, it is worth remembering that, according to the decision of the European Court, links cannot be subject to copyright.
Another way to harm a site is to slow down its speed by making multiple requests to the page. This is very difficult for a webmaster to notice. But if a search robot records this, the site loses positions.
Review bombing is also used to attack a competitive resource - creating hundreds of five-star ratings in a very short time. No less effective are complaints about a site, including viruses and spam mailings, which the "complainants" themselves and implemented by hacking the resource.
It is worth remembering that the funds invested in the negative SEO of competitors would be better invested in the development of your own resource. After all, if the attacked site is authoritative enough, attacks can not only harm its positions, but even improve ranking.

Link tracking tools:
- Screaming Frog
- Majesticseo. com
- Webmeup. com
- Web counter
- Ahrefs. com
- GWT
- Google Alerts
- Opensiteexplorer. org
- Raven-seo-tools
- Linkresearchtools. com
- Linkquidator. com
- Lenkdelete. com
- Ganbox
- Removeem. com
- Linkrisk. com
- Linksremove. com
What to do if you find low-quality links?
- try to contact the administrator and ask them to remove them,
- use the Google Disavow tool with the owner's rights,
- change the page URL so as not to lose content.
As a last resort, you can create a new domain, but in no case should you redirect to it from the downgraded site. In addition, you can write a letter to Google — but only if you follow all of its instructions perfectly.