How to Detect Look-alike Domain Registrations

Posted on November 25, 2020
Last updated on August 05, 2025.
Malicious domains play a central role in a wide range of cyberattacks that can severely damage a brand’s reputation. Spoofed domains are often quick and inexpensive to create, making them effective tools for launching phishing campaigns and distributing malicious emails. To identify and respond to domain-based threats targeting your organization, security teams must adopt advanced, well-defined processes for collecting and curating threat intelligence.
 
There's a massive number of suspicious domains across the threat landscape and threat actors increasingly improve look-alike domains to promote their trustworthiness. Among the methods used to evade detection is secure socket layer (SSL) certificates for phishing sites. 
 
To effectively protect against the high volume and growing sophistication of suspicious domains, security teams need to source and develop domain intelligence to identify potential threats and compile sufficient evidence for takedown. 
 

Collecting Domain Intelligence

Ongoing visibility into newly registered and existing domain registrations is necessary to proactively identify unauthorized domains. There are many different sources security teams can use to detect look-alike domains:
 
  • TLD zone files list every active, registered domain for that specific TLD created on a daily basis.
  • Secure Socket Layer certificate transparency logs present domains, subdomains, and so on for the millions of new SSL certificates issued daily.
  • DNS traffic contains domain names being queried and can be monitored for new domains.
  • DNS queries can be performed using look-alike variations of legitimate domains to see if variations currently exist.
 
Intelligence collected from these sources produces massive amounts of domain data and enables security teams to identify various domain threats. Using these resources also increases the speed of domain threat detection. For collection to be effective, security teams should continuously monitor for indicators of domain impersonation.
 

Curating Domain Intelligence

To accurately distinguish real domain threats from false positives, collected intelligence must be analyzed using a combination of automated tools and expert human review. Domain strings often include related or misleading terms, so analysts must evaluate both keywords and variations to assess whether a domain poses a legitimate threat.

Effective domain intelligence analysis involves three key steps:

  1. Score domain feed entries based on severity.

  2. Review each result in detail.

  3. Categorize the domain accordingly.

Key indicators that help determine whether a domain is a threat include:

The Domain String

Analysts need to determine if there are letters or symbols that would confuse an end user as well as how closely the domain string matches keywords. After review, the domain string should be scored based on its likelihood of being a legitimate threat. 
 

The Content

Analysts also should examine the content hosted on associated web pages. Key indicators of a suspicious domain include the presence of relevant data and whether the site appears to impersonate or reference a legitimate brand. In many cases, the relationship between the content and the domain is ambiguous, requiring further evaluation by appropriate business units.

If either the domain string or the hosted content raises suspicion, security teams should conduct a thorough review of all available data to identify any signs of malicious behavior. Additionally, it’s important to determine whether the domain has an active Mail Exchanger (MX) record, which designates the mail server responsible for handling email. The presence of an MX record may indicate the domain is being used for business email compromise (BEC), phishing, or spam campaigns.

Malicious domains can be leveraged in numerous ways to harm an organization. As threat actors continue to refine their evasion techniques, the ability to rapidly identify and analyze suspicious domains is essential. Implementing robust, end-to-end processes for threat collection and curation is critical to enabling timely and effective mitigation.

Ready to break the attack chain of fraud and brand Impersonation? Schedule a demo with Fortra Brand Protection to see us in action.

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