In cybersecurity, a wildcard domain refers to a domain name that uses a wildcard character (*) to represent one or more subdomains. It primarily simplifies DNS management by allowing a single DNS record to apply to all subdomains of a given domain. For example, a wildcard domain like *.example.com would match sub1.example.com, sub2.example.com, and any other subdomain under example.com.

Key Points about Wildcard Domains in Cybersecurity:

1. Simplification of DNS Management:

   • Efficiency: Reduces the need to create separate DNS records for each subdomain.

   • Flexibility: Allows for dynamic subdomain creation without needing to update DNS records.

2. Security Implications:

   • Expanded Attack Surface: Attackers can exploit wildcard domains to create subdomains for malicious activities, such as phishing or distributing malware.

   • DNS Hijacking Risks: If the DNS server managing the wildcard domain is compromised, all subdomains can be redirected to malicious sites.

   • Certificate Management: Wildcard SSL/TLS certificates can be issued for wildcard domains, meaning a single certificate can secure all subdomains. It can be convenient but poses risks if the private key is compromised.

3. Misuse and Abuse:

   • Phishing and Scams: Attackers can create convincing subdomains (e.g., login.example.com) to trick users into providing sensitive information.

   • Subdomain Takeover: If a subdomain points to a cloud service or third-party host and is not managed correctly, an attacker can take control of the subdomain if the original service is not in use.

4. Mitigation and Best Practices:

   • Monitoring and Auditing: Regularly monitor DNS records and audit subdomains to detect unauthorized or suspicious activities.

   • Access Controls: Implement strict access controls and robust authentication methods to secure DNS management interfaces.

   • Limit Wildcard Usage: Use wildcard domains sparingly and only when necessary to minimize the potential attack surface.

Example:

Consider the domain example.com. Setting up a wildcard DNS record for *.example.com means that any subdomain (like shop.example.com, blog.example.com, etc.) will resolve to the same IP address specified in the wildcard record.

While wildcard domains offer convenience and flexibility in managing DNS records, they must be carefully managed and secured to prevent potential abuse and security risks. Proper implementation, monitoring, and adherence to best practices are crucial to mitigating the associated risks in a cybersecurity context.

ThreatNG, as an EASM/DRP solution with its comprehensive Domain Intelligence Investigation Module, can significantly aid organizations, their third parties, and supply chains in managing the risks associated with wildcard domains. Here's how:

ThreatNG's Capabilities:

• Domain Intelligence Investigation Module: This module offers a combination of functionalities that directly address wildcard domain risks. These include:

  • Subdomain Intelligence: Identifies all subdomains associated with a domain, including those potentially created using a wildcard certificate.

  • Certificate Intelligence: Analyzes SSL/TLS certificates for validity, expiration, and type (including wildcard certificates).

  • Exposed API Discovery: Discovers APIs hosted on identified subdomains, which could be vulnerable if a wildcard certificate is compromised.

  • Web Application Hijack Susceptibility Assessment: This evaluation evaluates the likelihood of a subdomain being exploited for malicious purposes due to vulnerabilities.

Benefits for Organizations and Supply Chain:

1. Identifying Rogue Subdomains: ThreatNG's subdomain intelligence helps uncover all subdomains under a domain, including those potentially created with a wildcard certificate. It allows organizations to identify any unauthorized or unexpected subdomains that could be malicious.

2. Assessing Certificate Security: The certificate intelligence feature analyzes certificates for validity, expiration, and type. It allows organizations to ensure their wildcard certificates are valid, not nearing expiration, and not compromised.

3. Protecting APIs: Exposed API discovery helps identify APIs hosted on subdomains secured with wildcard certificates. This allows organizations to implement additional security measures to prevent unauthorized access in case of a certificate breach.

4. Prioritizing Remediation: The Web Application Hijack Susceptibility assessment helps prioritize which subdomains (potentially secured by wildcards) require the most urgent attention based on their vulnerability to hijacking attempts.

Collaboration with Complementary Solutions:

ThreatNG works seamlessly with other security solutions:

• Security Information and Event Management (SIEM): ThreatNG can integrate with SIEM systems to provide real-time alerts on suspicious subdomain activity or compromised certificates related to wildcard domains.

• Vulnerability Scanners: ThreatNG can share information about discovered subdomains with vulnerability scanners to prioritize vulnerability assessments on potentially vulnerable subdomains secured with wildcards.

• Phishing Detection Tools: ThreatNG can integrate with phishing detection tools to identify potential phishing attempts leveraging subdomains created with a wildcard certificate.

Handoff Examples:

1. ThreatNG identifies a new subdomain secured with a wildcard certificate. ThreatNG would alert the security team, who can investigate the subdomain's legitimacy. If unauthorized, they can contact the domain owner to take action.

2. ThreatNG detects an expiring wildcard certificate. ThreatNG would alert the security team, who can initiate the certificate renewal process before it expires and leaves subdomains vulnerable.

3. ThreatNG identifies an exposed API on a subdomain secured with a wildcard certificate. ThreatNG would alert the security team, which can investigate the API's purpose and implement additional access control measures to mitigate risks.

By providing comprehensive visibility into subdomains and their security posture, ThreatNG empowers organizations and their supply chain to manage the risks associated with wildcard certificates effectively. This collaborative approach and complementary security solutions allow for a proactive and layered defense against potential threats.