Subdomain Takeover Vulnerability
A subdomain takeover vulnerability occurs when an attacker gains control of a subdomain no longer actively used by its legitimate owner.
Here's a breakdown of how it happens:
Subdomains: Organizations often organize different parts of their online presence. For example, a company might use "blog.example.com," "store.example.com," or "support.example.com."
Third-Party Services: Companies frequently use third-party services to host content or provide subdomain functionality. Common examples include:
Cloud storage services (e.g., Amazon S3 buckets)
Content Delivery Networks (CDNs)
Website hosting platforms
Email marketing services
DNS Records: A DNS (Domain Name System) record is created to connect a subdomain to a specific service. This record tells browsers where to go when someone types in that subdomain.
The Vulnerability: The problem arises when a company stops using a particular third-party service but fails to remove the corresponding DNS record.
The Takeover: An attacker can create an account with that same third-party service and claim the abandoned subdomain. Because the DNS record still points to that service, the attacker can host their own content on that subdomain.
Consequences of a Subdomain Takeover:
Phishing Attacks: Attackers can use the hijacked subdomain to host phishing pages that mimic the legitimate website, tricking users into providing sensitive information.
Malware Distribution: Attackers can distribute malware from the subdomain, infecting visitors' computers.
Website Defacement: Attackers can replace the original content with their own, damaging the organization's reputation.
Search Engine Optimization (SEO) Harm: Attackers can negatively impact the organization's SEO by posting irrelevant or harmful content on the subdomain.
ThreatNG offers powerful capabilities to help organizations defend against subdomain takeover vulnerabilities. Here's a detailed explanation of how ThreatNG addresses this specific threat:
ThreatNG's external discovery process is the first line of defense. ThreatNG identifies all of an organization's subdomains by performing purely external and unauthenticated discovery. This comprehensive enumeration is critical because attackers often look for forgotten or abandoned subdomains to target. ThreatNG's ability to discover these subdomains, even those that might not be well-documented, provides a complete picture of the organization's attack surface.
ThreatNG's external assessment capabilities include a specific "Subdomain Takeover Susceptibility" rating. This assessment pinpoints vulnerabilities that make subdomains susceptible to takeover.
Domain Intelligence Analysis: ThreatNG's assessment heavily relies on its Domain Intelligence module. This module analyzes various aspects of an organization's subdomains, including:
DNS Records: ThreatNG examines DNS records associated with each subdomain. This is crucial because outdated or misconfigured DNS records are the primary cause of subdomain takeover vulnerabilities. For example, ThreatNG can detect CNAME records pointing to a service the organization no longer uses.
SSL Certificate Statuses: ThreatNG also assesses the status of SSL certificates associated with subdomains. Inconsistencies or missing certificates can also indicate potential vulnerabilities.
By analyzing these factors, ThreatNG provides a clear picture of which subdomains are at risk.
3. Reporting
ThreatNG's reporting capabilities are vital for communicating the risk of subdomain takeovers to relevant stakeholders.
Prioritized Reports: ThreatNG's reports prioritize vulnerabilities based on their severity. This allows security teams to focus on the subdomains that pose the most immediate risk of being taken over.
Technical Reports: Detailed technical reports provide security teams with the specific information they need to remediate subdomain takeover vulnerabilities, such as the exact DNS records that need to be updated.
Executive Reports: Executive summaries can help management understand the business impact of subdomain takeovers, such as potential damage to brand reputation or loss of customer trust.
ThreatNG's continuous monitoring feature is essential for promptly detecting subdomain takeover vulnerabilities.
Dynamic Changes: DNS records and third-party service usage can change frequently. Continuous monitoring ensures that ThreatNG detects any new or emerging subdomain takeover risks.
Proactive Alerts: ThreatNG can alert security teams to any changes that increase a subdomain's susceptibility to takeover, allowing for rapid response.
ThreatNG's investigation modules provide security teams with the tools to investigate and understand subdomain takeover vulnerabilities in greater detail.
Domain Intelligence Module: The Domain Intelligence module is particularly relevant. It allows security teams to:
Drill down into DNS Records: Security teams can use this module to examine the DNS records of any subdomain in detail, identifying the exact misconfigurations that make it vulnerable to takeover.
Track Changes Over Time: The module may also allow security teams to track changes to DNS records over time, which can help identify when a vulnerability was introduced.
Enumerate Subdomains: The module provides a comprehensive list of subdomains, ensuring that none are overlooked in the investigation.
ThreatNG's general intelligence repositories contribute to a broader understanding of risks.
Threat Intelligence: Information on common attacker tactics and techniques can help security teams understand how subdomains are typically targeted.
7. Synergies with Complementary Solutions
ThreatNG's capabilities can be significantly enhanced by working with other security solutions:
DNS Management Tools: ThreatNG can complement DNS management tools by providing alerts about vulnerable DNS configurations. DNS management tools can then quickly and easily remediate those vulnerabilities.
Asset Management Systems: ThreatNG's subdomain inventory can be integrated with asset management systems to provide a more complete view of an organization's digital assets. This integration can help ensure that all subdomains are correctly managed and secured.
Web Application Firewalls (WAFs): If a subdomain is being used to host a web application, a WAF can provide an additional layer of protection against attacks that might be launched through that subdomain, even if it is not taken over.
Examples of ThreatNG Helping:
Detecting Orphaned CNAME Records: ThreatNG can identify subdomains with CNAME records pointing to cloud storage services that the organization no longer uses, preventing attackers from claiming those subdomains.
Alerting to DNS Changes: ThreatNG can alert security teams to unauthorized or suspicious changes to DNS records, which could indicate an attempted takeover.
Providing a Subdomain Inventory: ThreatNG provides a complete inventory of all subdomains, including those not actively used, ensuring that none are forgotten and left vulnerable.
By combining these capabilities, ThreatNG offers a robust solution for identifying, assessing, and mitigating the risk of subdomain takeover vulnerabilities.
