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Securd's Greywall: Improve Cybersecurity with Advanced DNS Filtering and Threat Hunting


The cybersecurity landscape is a continually evolving battlefield. Security solutions must innovate and adapt dynamically to keep pace with sophisticated threats and persistent threat actors. One such innovative solution is Securd's Greywall.


Greywall, a proprietary feature offered by Securd, revolutionizes how DNS filtering and threat hunting are exercised, enhancing the security posture of organizations by intelligently blocking potential threats. This blog explores how Securd's Greywall works and presents an illustrative example demonstrating its effectiveness in mitigating cyber threats.

Securd's Greywall: A Sentry on Watch

Picture the Greywall as an astute gatekeeper. Instead of blindly trusting or denying entry to all guests, it analyzes each visitor based on their past behavior and the current scenario. Here's what makes the Greywall stand out:

  • It learns which domains are trustworthy and allows them to be resolved.

  • It is aware of untrusted domains and temporarily blocks them.

  • The security administrator sets the temporary block duration in the Greywall. This block can range from an hour to 90 days.

  • This temporary block buys time for security tools and the information security community to assess and mitigate a cyber threat.

The Greywall provides a dynamically controlled environment, ensuring that only validated and safe domain requests are resolved.

Breaking Free from the Constraints of Global Blocklists

Global blocklists can sometimes miss malicious domains, especially those that threat actors "groom" to make them appear trustworthy. Here's where Securd's Greywall offers an enhanced solution:

  • It allows you to create multiple companies, with each Greywall being isolated.

  • New domain observation and Greywall analytics are contained within that tenant.

  • What matters is when the domain first interacted with your endpoints, not when it was observed globally.

  • Administrators set the rules on when a new domain can be resolved, if at all.

These configuration options make Securd's Greywall a more targeted and efficient solution than traditional blocklists.


Greywall in Action: Thwarting a Phishing Threat


Let's consider an example to understand Greywall's utility better. Imagine a scenario where a threat actor registers a domain and launches a phishing campaign within 15 minutes. An end-user is tricked into clicking on a phishing link, which initiates a DNS lookup.

Here's how Greywall steps in:

  1. The Greywall checks if the DNS query to the malicious domain has been observed before or if the domain possesses characteristics that disallow it to be implicitly trusted.

  2. If it matches any block criteria, the query will be denied, redirecting the user to a block page and logging the blocked traffic for review.

  3. Once the Greywall criteria for the domain expire, the Greywall will allow the DNS query to continue, subjecting it to additional security measures to ensure it is not an active threat.

In essence, Greywall acts as an intelligent sentry, regulating traffic based on its threat level and ensuring an adaptable and robust line of defense.


Evolving with Cyber Threats: Greywall's Proactive Approach


Securd's Greywall feature signifies a new DNS filtering and threat-hunting era. It takes a proactive stance, constantly learning and adapting to new threats, making it an invaluable ally in an organization's cybersecurity arsenal. The flexibility to set the rules based on individual company needs adds further customization, strengthening the security posture against evolving cyber threats.


Securd's Greywall stands as a testament to the evolving nature of cybersecurity solutions by adapting to new threats and offering a proactive defense mechanism. As the world of cyber threats grows more complex, solutions like our Greywall, offering adaptive and intelligent defense mechanisms, will continue to be crucial components in the cybersecurity toolkit.

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