In 2025, hackers are predicted to increasingly manipulate search engine results to deceive users, making SEO poisoning a powerful weapon for phishing, malware distribution, and data theft. While subdomain takeovers were already one of the most common vulnerabilities found in 2024, attackers are expected to conduct not just hijacking of subdomains but actively ensuring they rank at the top of search results.
SEO Poisoning Explained
SEO poisoning (also known as search poisoning or malvertising) is a cyberattack technique where threat actors manipulate search engine optimization (SEO) tactics to make malicious websites appear at the top of search engine results.
Search engines like Google rank web pages based on factors like keywords, backlinks, and user engagement. Cybercriminals exploit these ranking systems using various deceptive techniques to push their malicious sites higher in search results.
Traditional SEO Poisoning Techniques
- Keyword Stuffing – Overloading webpages with popular search terms to trick search engine algorithms into ranking the site higher.
- Cloaking – Showing different content to search engine crawlers than what users see when they click the link. This makes the site appear legitimate in search results while actually hosting malicious content.
- Manipulating Search Rankings – Using bots or paid users to click on links and artificially increase the website’s ranking.
- Private Link Networks – Creating fake websites that link to the malicious site, making it appear more trustworthy to search engines.
Emerging SEO Poisoning Method
Instead of creating a new site and manipulating the search engine results Hadrian predicts that hackers will increasingly utilize the victim’s own website. Marketing teams spend a lot of time and effort to ensure their sites are ranked at the top of search results, by taking over a portion of a site a hacker can hijack the results so that their pages appear at the top.
How Subdomain Takeover (Hijacking) Works
Subdomain takeover (or subdomain hijacking) occurs when an attacker gains control of an organization's subdomain due to misconfigured or abandoned DNS settings. This typically happens when a subdomain still has a CNAME record in the DNS system, but no active host is providing content for it. This vulnerability is common when a site is abandoned, but its DNS records are not updated to remove the outdated subdomain.
DNS records guide browsers to the correct destination for a website, one type is called a CNAME record and points from one domain to another. For example, an organization with the domain example[.]com, may create a new subdomain name of blog[.]example[.]com. Typically this subdomain is set as an alias to the parent domain, in this case, blog[.]example[.]com, will have a CNAME record that points to example[.]com.
A common misconception is that a CNAME record must always resolve to the same website as the domain it points to, but this isn't always true. Hackers can abuse this to point seemingly trustworthy URLs to their own malicious content.
Subdomains become vulnerable to hijacking when an organization discontinues a cloud service but fails to update or remove the corresponding DNS records. Similarly, if an organization forgets to renew a domain name, it can be purchased by anyone, increasing the risk of exploitation.
The Impact of SEO Poisoning
The impact of these attacks extends beyond immediate financial loss. Companies that fall victim risk significant damage to their brand reputation and customer trust, as users mistakenly believe they are interacting with a legitimate website. Businesses that rely on online transactions, especially e-commerce, banking, and retail sectors, are prime targets due to the high value of user data.
In 2022, Google researchers uncovered a campaign leveraging SEO poisoning to trick victims into downloading BATLOADER malware as an initial entry point. The attackers used SEO keywords such as “free productivity app installation” and “free software development tool installation” to attract victims to compromised websites. Once on the site, users were prompted to download a malicious installer that bundled legitimate software with BATLOADER malware. The BATLOADER malware could be used to steal user credentials or install ransomware.
SEO Poisoning on the Rise
Hadrian has noted an increase in the number of tools used by hackers to identify dangling CNAME records that could be exploited. And, through the use of AI-generated content, cybercriminals can quickly make these malicious domains appear credible, luring unsuspecting users into revealing sensitive information or completing fraudulent transactions.
The tools used by hackers has steadily grown more sophisticated, increasingly relying on automation to conduct internet wide attacks. Pre-built tools can also lower the barrier of entry for attackers, enabling even less skilled individuals to execute large-scale attacks with little effort.
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Preventing Subdomain Takeovers
As organizations grow, DNS infrastructure becomes increasingly complex, heightening the risk of misconfigurations that can be exploited. Hadrian provides comprehensive DNS security to prevent subdomain hijacking.
Centralized DNS Visibility
Hadrian provides centralized visibility into your DNS infrastructure, identifying unclaimed or misconfigured subdomains before they become security risks. By detecting vulnerable subdomains early, organizations can proactively secure their attack surface.
Continuous Monitoring for Issues
Manually tracking dynamic DNS infrastructure is challenging, leaving organizations exposed to subdomain takeovers. Hadrian automates this process with continuous scanning, identifying subdomains that could be exploited for phishing, malware distribution, or other malicious activities. With real-time insights, security teams can remediate vulnerabilities before attackers exploit them.
By proactively monitoring and securing your DNS landscape, Hadrian helps organizations prevent subdomain takeovers and protect their brand, customers, and data. To learn more get in touch with one of our experts.
