Subdomain Takeover Mandates
Subdomain Takeover Mandates, in the context of cybersecurity and External Attack Surface Management (EASM), are explicit, prioritized, and non-negotiable operational directives issued to security and IT teams to identify, confirm, and remediate Subdomain Takeover vulnerabilities immediately.
Purpose and Function
The primary purpose of a Subdomain Takeover Mandate is to establish a high-certainty, rapid-response process that eliminates "dangling DNS" risks, which are critical external attack vectors. These mandates move the responsibility from general policy compliance to specific, actionable security engineering tasks with defined deadlines.
High-Priority Directive: Subdomain takeovers exploit a specific condition: a Canonical Name (CNAME) record in a company's DNS points to a third-party service (such as an external cloud provider, SaaS platform, or content delivery network) that the company no longer uses or has neglected to provision. The mandate elevates the remediation of this specific, confirmed vulnerability above most other issues due to the high risk of severe consequences, including brand damage, session hijacking, phishing attacks, and data theft.
Evidence-Based Requirement: Effective mandates are driven by irrefutable evidence from continuous monitoring systems confirming the target external resource's inactive or unclaimed status. The mandate is not based on a general audit finding, but on the certainty that a hostile actor can register the unclaimed external resource and effectively "take over" the company's subdomain.
Required Remediation Actions: The mandate typically enforces one of two immediate, prescribed remediation actions:
DNS Record Removal: The most secure resolution is to immediately delete the CNAME record from the authoritative DNS zone, severing the dangling connection.
External Resource Claim: If the subdomain is still needed, the mandate requires the immediate provisioning or claiming of the external resource (e.g., creating the bucket or application instance) on the third-party platform to prevent an attacker from claiming it first.
Governance and Audit Trail: The mandate requires strict logging and reporting of the remediation timeline, the responsible team, and the final state (i.e., whether the record was removed or the resource was claimed). This creates a clear audit trail demonstrating regulatory compliance with controls over external assets and the ability to mitigate high-risk exposures proactively.
These mandates transform the mitigation of a complex, infrastructure-level vulnerability into a standardized, urgent security operation.
The concept of Subdomain Takeover Mandates is directly supported and operationalized by ThreatNG's capabilities, providing the necessary certainty and high-priority context to transform a potential vulnerability into a non-negotiable, urgent remediation task.
ThreatNG’s Role in Enforcing Subdomain Takeover Mandates
ThreatNG’s external, unauthenticated assessment provides the irrefutable evidence—known as Legal-Grade Attribution—that forms the basis of the mandate, ensuring the risk is immediately prioritized and resolved.
1. External Discovery
ThreatNG performs purely external unauthenticated discovery, identifying all associated subdomains of an organization. This ensures that all potential targets for a takeover, including forgotten or unmonitored assets with "dangling DNS" records, are visible and included in the mandate's scope.
2. External Assessment
The Subdomain Takeover Susceptibility assessment is the specific mechanism that provides the mandatory evidence.
Evidence Generation: ThreatNG's core check uses DNS enumeration to identify CNAME records pointing to third-party services, such as Cloud & Infrastructure (e.g., AWS/S3 or Heroku), Development & DevOps (e.g., GitHub or Vercel), or Website & Content platforms (e.g., Shopify or WordPress).
Certainty and Prioritization: The crucial step is the specific validation check to determine whether the CNAME is currently pointing to an inactive or unclaimed resourceon that vendor's platform. This confirmation of the "dangling DNS" state provides the irrefutable proof necessary to issue a mandate and prioritize the risk.
Example: ThreatNG discovers the subdomain staging.companydomain.com has a CNAME record pointing to an unclaimed Amazon S3 bucket on a third-party AWS service. The resulting Subdomain Takeover Mandate would demand: "Immediately remove the CNAME record for staging.companydomain.com by 5:00 PM today, as ThreatNG has confirmed the destination AWS/S3 bucket is unclaimed, posing an immediate takeover threat." The accompanying security rating (A-F, with A being good and F being bad) dictates the urgency of the mandate.
3. Investigation Modules
The Investigation Modules provide the contextual backing and formal directive needed to make the mandate effective.
Contextual Risk Intelligence (Context Engine™): This solution achieves Irrefutable Attribution by correlating the technical finding (the dangling DNS) with decisive business context. This correlation, which delivers Legal-Grade Attribution, provides the absolute certainty required to justify the mandate to the boardroom and eliminate the Contextual Certainty Deficit. It converts the technical vulnerability into a known, high-impact business risk.
Correlation Evidence Questionnaire (CEQ): This dynamically generated solution leverages the Context Engine™ to find irrefutable, observed evidence. While focused on questionnaires, its underlying function is to validate external risk. If a subdomain takeover risk is found, the CEQ can be used to generate a mandate-focused question: "Confirm the current business owner of the asset using the unclaimed CNAME staging.companydomain.com and provide photographic evidence of DNS record deletion by the deadline."
4. Intelligence Repositories
The repositories provide the necessary reference data and threat context to justify the mandates' extreme urgency.
Vulnerabilities (DarCache Vulnerability): While not a direct takeover check, the repository’s inclusion of KEV (Known Exploited Vulnerabilities) provides context on how actively external exposures are being weaponized. An organization can strengthen its mandate by referencing that subdomain takeover is a well-known initial access vector used in many KEV-related attacks.
Technology Stack: The Technology Stack Investigation Module provides exhaustive, unauthenticated discovery of the technologies on the target's external attack surface. By confirming the specific vendors (e.g., Vercel, Heroku, Shopify) that the CNAME is pointing toward, the mandate gains specificity. It allows the remediation team to know which third-party cloud platform is involved immediately.
5. Continuous Monitoring
Continuous Monitoring is essential to ensure compliance with the mandate. Once a subdomain is flagged as a risk, ThreatNG’s continuous monitoring capability ensures that if the record is not removed, the high-risk finding persists, continuously flagging the compliance failure until the mandate is satisfied.
Collaboration with Complementary Solutions
ThreatNG's high-certainty findings are used to support solutions that manage compliance and incident response.
Complementary Solutions for IT Service Management (ITSM) and Ticketing: The high-certainty finding of a confirmed subdomain takeover susceptibility (Legal-Grade Attribution) and its high-risk prioritization can be automatically pushed to an ITSM solution like ServiceNow. This immediately generates a high-priority, non-negotiable ticket with a strict service level agreement (SLA) for the DNS/Network team, bypassing standard low-priority ticket queues that might delay critical remediation.
Complementary Solutions for GRC Platforms: The External GRC Assessment mapping, which includes PCI DSS and ISO 27001, can cooperate with a GRC platform. The confirmed subdomain takeover vulnerability constitutes a severe control failure in external asset management. ThreatNG feeds this verifiable evidence into the GRC platform, allowing it to instantly update the overall risk posture and compliance score with a high-confidence failing mark, thereby demonstrating to auditors why the mandate was necessary.
