A "Zombie DNS record" is essentially synonymous with a "dangling," "stale," or "orphaned" DNS record. It refers to a DNS entry that continues to exist and resolve, even though it points to a resource (like a website or server) that is no longer active, available, or under the control of its original owner.

How it Can Lead to a Subdomain Takeover:

The mechanism by which a zombie DNS record leads to a subdomain takeover is identical to that of other dangling records:

1. Resource Decommissioning or Expiration: A company might shut down a service, migrate it to a new platform, or let a domain name expire without updating or removing the associated DNS records.

2. Zombie DNS Record Persists: The DNS record remains in the DNS zone file, even though the resource it points to no longer exists or is unclaimed.

3. Attacker Identification: A malicious actor discovers this zombie DNS record and recognizes the opportunity for exploitation.

4. Resource Recreation: The attacker creates a new resource on the same platform or with a configuration similar to the original.

5. Subdomain Takeover: Since the zombie DNS record is still active, it inadvertently directs traffic to the attacker's newly created resource.

6. Malicious Activity: The attacker gains control of the subdomain and can use it for phishing, malware distribution, or traffic redirection.

Key Points:

• Zombie DNS records pose a severe security threat as they can facilitate subdomain takeovers.

• Regular DNS audits and prompt cleanup of unused or outdated records are crucial for preventing such attacks.

• CNAME records are particularly vulnerable as they directly point to other domains or hostnames, making them easy targets for takeover if the target resource becomes unclaimed.

• Organizations must prioritize proper DNS hygiene to avoid the potential consequences of subdomain takeovers, including data breaches, financial loss, and damage to brand reputation.

Remember: The term "zombie" emphasizes that the DNS record, though technically still "alive" in the DNS system, points to a "dead" or defunct resource, creating a security loophole that attackers can exploit.

ThreatNG employs a proactive and comprehensive strategy to identify and mitigate vulnerabilities that could lead to subdomain takeovers:

Deep Discovery and Assessment:

• Domain Intelligence:

• DNS Intelligence: Continuously scans DNS records, meticulously examining CNAME, A, and other record types for misconfigurations or inconsistencies that might signal potential takeover opportunities.

• Subdomain Intelligence: Thoroughly maps and assesses all active and inactive subdomains, identifying any exhibiting vulnerabilities or signs of neglect.

• Certificate Intelligence: Monitors SSL certificates for expiration, mismatches, or other irregularities that could leave subdomains open to exploitation.

• Cloud and SaaS Exposure:

• Sanctioned/Unsanctioned Cloud Services: This tool discovers the organization's cloud resources, pinpointing any unmanaged or forgotten services with associated DNS records.

• Cloud Service Impersonations: This feature detects attempts to impersonate legitimate cloud services, which could be a precursor to a subdomain takeover.

• Exposed API Discovery & Exposed Development Environment Discovery:

• Uncovers publicly accessible APIs and development environments that might inadvertently expose sensitive subdomain information or provide an entry point for attackers.

• Technology Stack:

• Identifies the organization's technologies and services, allowing for targeted assessment of its known vulnerabilities and potential misconfigurations that could contribute to subdomain takeover susceptibility.

Continuous Monitoring and Alerting:

• Continuous monitoring of all discovered assets and configurations for any changes or anomalies that could indicate a heightened risk of subdomain takeover.

• Prompt alerts to security teams when vulnerabilities or suspicious activities are detected, enabling swift response and remediation.

• Integration with existing security solutions to automate workflows and facilitate efficient incident response.

Intelligence Enrichment and Contextualization:

• Dark Web Presence:

• Monitors underground forums and marketplaces for discussions or evidence of malicious actors targeting the organization's subdomains.

• Identifies any compromised credentials or sensitive data leaks that could be leveraged in a subdomain takeover attempt.

• Compromised Credentials:

• Tracks data breaches and credential leaks that could expose user accounts with access to DNS management or cloud services, increasing the risk of unauthorized subdomain changes.

• Known Vulnerabilities:

• Maintaining an up-to-date database of vulnerabilities affecting various technologies and services the organization uses enables proactive identification and remediation of weaknesses that could be exploited in a subdomain takeover.

Complementary Solutions Integration:

ThreatNG seamlessly integrates with other security tools to enhance its subdomain takeover prevention capabilities:

• Web Application Firewalls (WAFs): WAFs can be configured to block traffic to or from vulnerable subdomains, mitigating potential attacks.

• Vulnerability Scanners: Regular vulnerability scans can help identify and address subdomain weaknesses that could be exploited.

• Security Information and Event Management (SIEM) Systems: SIEMs can collect and correlate data from ThreatNG and other security tools to provide a holistic view of the organization's security posture and facilitate incident response.

Examples:

• Dangling CNAME Record: ThreatNG's DNS Intelligence module detects a CNAME record pointing to a decommissioned third-party service. The Subdomain Takeover Susceptibility assessment flags this as a high-risk vulnerability, prompting immediate action to remove the record or reconfigure the subdomain.

• Exposed Development Environment: The Discovery capability identifies a staging server accessible from the internet, potentially exposing sensitive subdomain information. ThreatNG alerts the security team, allowing them to secure the environment and prevent unauthorized access.

• Leaked Credentials on the Dark Web: ThreatNG's Dark Web Presence module uncovers leaked credentials for users accessing the organization's DNS management system. The security team is promptly alerted, enabling them to reset the compromised credentials and prevent a potential subdomain takeover.

ThreatNG's comprehensive capabilities and proactive approach make it a powerful tool for identifying and mitigating subdomain takeover susceptibility. By combining in-depth discovery, continuous monitoring, and intelligence enrichment with seamless integration with complementary solutions, ThreatNG empowers organizations to protect their critical assets and maintain a robust security posture in the face of evolving threats.