Note: I’m not a negative SEO attack expert. There are people in this industry that are incredibly skilled at this one area in ways that I am not. However, I recently paused my Master’s in Cyber Security, and that has sparked my interest in exploitation techniques. With that out the way, let’s continue.
Negative SEO attacks are rife in the industry, yet are largely misunderstood. I’ve been wanting to put together a guide on various negative SEO attacks, but this is no trivial task. The attacker’s mind is a curious one—ever evolving, growing, and learning. By the time a technique is documented, its payoff may have already passed.
A friend recently contacted me about a peculiar situation on a website he was working on. He noticed that while their SEMRush authority score continued dropping, the velocity of referring domains and backlinks was strong—typical for spammy backlink attacks.
His notes included the following:
“Their backlink profile has a high toxicity score with thousands of domains that are being classed as toxic or potentially toxic in SEMrush.”
So far, this sounds like a classic negative SEO attack.
“I'm also noticing in their GSC that overall traffic has decreased in the last few months, particularly for their product pages. When I checked the page report, there was a massive increase in noindexed pages—automatically flagged by Google as 404s. And they are random, spammy internal pages.”
In GSC, it looks something like this:
[INSERT IMAGE HERE]
These backlinks are growing rapidly—from 25,000 in September to 40,000 in October and over 60,000 in December. Additionally, the crawl stats report shows intermittent spikes, as Google allocates CPU time to these falsely generated pages.
Because he has first-party data I don’t have access to, I know the website’s overall performance is declining. This has been a recurring theme in 2023—with updates in April, October, and the two November updates (core and secondary).
Based on his observations:
- The website’s authority score is dropping in SEMRush.
- Its rankings are falling in both GSC and SEMRush.
- Visibility for category and product pages is decreasing.
- There is a large influx of randomly generated 404 pages in GSC.
When he mentioned the auto-generated 404s, I was intrigued:
“Can you check their 404 template and tell me if it can be indexed?”
“Their 404 page is index follow.”
I advised him to create a deliberately random 404 page—something like:
domain.com/beachballpineapple
He did, confirmed via the meta robots tag that the page could indeed be indexed, and from there the investigation began.
Google will crawl 404 pages—sometimes repeatedly—to determine their value. While it’s normal for legacy pages with backlinks to be revisited, this scenario involves thousands of 404s generated within months, all stored in Google’s crawl report. Notably, these URLs aren’t entirely random; they return valid pages that redirect to functioning external websites, indicating human intervention. This is starting to look like a highly engineered attack.
Negative SEO Strategy One: Index, DoFollow Custom 404 Pages
The attacker has exploited a vulnerability in the custom 404 page template. Although the page returns an HTTP 404 status, it is marked as Index, Follow, instructing Google to crawl and index it.
If this were a one-off mistake, it might not matter. But these attackers aren’t novices—they’re part of an organized effort. Many of the URLs even redirect to spammy sites like OnlyFans or “dating” Instagram pages mimicking Instagram’s CSS. There are now over 60,000 crawlable 404 pages linked to this website.
Furthermore, while Google is smart, it might still be getting tripped up by the association of this website with a host of spammy sites. It’s also worth noting that the website is based in the Nordics—where spam filters might not be as robust as in other territories.
How This Strategy Affects Websites
- Influx of 404 Pages: A mass of 404 pages redirecting to “bad” websites.
- Crawl Budget Wastage: Google's crawl budget is gradually eaten up.
- Negative Signals: The website starts being associated with spammy sites.
For a site with around 2,500 indexed pages, crawl bloat might be minimal—but it quickly becomes a client management issue. When a client sees these pages in GSC, you need to have an insightful response ready.
Negative SEO Strategy Two: Spam Blast From “Bad” Websites
In addition to the custom 404 vulnerability, the site is facing another attack. Recently, incoming domains have started linking to the site—sometimes with 20K, 30K, or even 40K backlinks from a single referring domain.
While this may seem alarming, it’s a somewhat outdated tactic. Typically, these are GSA links sold on platforms like Fiverr. Google, however, has invested significant effort into fighting link spam. Most of these backlinks are likely to be flagged as junk and algorithmically disavowed.
How This Strategy Affects Websites
- Massive Influx of Backlinks: A sudden surge of links from low-quality sources.
- Panic for Website Owners: Clients may see these spikes and worry, even if Google eventually discounts them.
- Simple Fix: Often, adding a single domain to the disavow file resolves the issue.
Even though category and product pages might get blasted, this type of attack rarely tanks a site completely.
Negative SEO Strategy Three (Bonus): Indexing Internal Search Results
I label this as a “bonus” strategy because the site in question didn’t suffer from it, but I’ve seen similar issues on many eCommerce sites. This problem is more common in custom CMSs where developers aren’t well-versed in handling internal search results.
You should never index internal search result pages for two main reasons:
- Bloat: They are generated so frequently that they cause massive bloat.
- Manipulation: They can be exploited by attackers to build bad URL strings with manipulated page titles and content.
A better approach is to record actual search queries (via GA or backend systems) and then create static, live URLs that address those queries. You can also integrate auto-suggest features with popular plugins or Elastic for enhanced CRO.
How This Strategy Affects Websites
- Indexable Bloat: Uncontrolled internal search results create numerous indexable pages.
- Keyword Cannibalization: This can lead to large-scale keyword cannibalization, negatively impacting organic visibility.
If uncontrolled, these pages can compete with your primary category and product pages, undermining your overall SEO efforts.
In Closing: How I Would Negative SEO A Website
If I were inclined to launch a negative SEO attack—and trust me, I’m really not—I would use methods based on known ranking factors. A proper negative SEO attack would be expensive and methodical.
- I doubt that GSA’ing a website is as effective as many believe.
- I also question the efficacy of inducing large-scale crawl bloat.
Instead, I would begin with a “normal” link building campaign targeting money pages, using on-target anchors and essentially over-optimizing those pages. Initially, these pages might rank well and attract keywords, leading website owners to dismiss the attack. But when link footprint algorithms kick in, the negative effects will become apparent. With the next algorithm update, those pages could be flagged and suffer significant penalties.
Once the site’s performance starts declining, I would then unleash the aforementioned attacks—overloading the site and consistently driving it down. I believe this approach, though resource-intensive and requiring patience, is a viable strategy. After all, every experienced SEO has crashed and burned a few websites—it’s how we learn.
Note: This post is for educational purposes only. Negative SEO’ing websites can lead to serious consequences. If traced back to you, such actions could destroy a business and have lasting legal ramifications. Please think before you act maliciously on the internet.