External CDE Footprint
In cybersecurity, the External CDE Footprint refers to the aggregate of all internet-facing assets, digital properties, and publicly discoverable information that could directly or indirectly impact the security of an organization's Cardholder Data Environment (CDE). The CDE is a network or system segment that stores, processes, or transmits sensitive payment card data.
The External CDE Footprint encompasses everything an attacker can observe and interact with from outside an organization's perimeter that might lead to a compromise of the CDE. This includes both explicitly known and often overlooked components:
Network Infrastructure: Public IP addresses, domains, subdomains, DNS records, and open ports that could be used as entry points or reveal network architecture related to the CDE.
Web and Mobile Applications: All public-facing web applications, mobile applications, and their associated APIs that handle or interact with payment card data, including login pages, e-commerce portals, and customer service interfaces.
Cloud and Third-Party Services: Any cloud storage buckets, SaaS applications, or other third-party services that store, process, or transmit cardholder data, or that, if compromised, could provide a pathway to the CDE. This also extends to the external security posture of those third-party providers.
Code and Development Exposures: Publicly accessible code repositories (e.g., GitHub, GitLab) that might inadvertently contain sensitive information like API keys, database credentials, or internal network configurations that could grant access to the CDE.
Digital Brand Presence: Typosquatted domains, look-alike websites, or social media accounts that could be used for phishing or social engineering attacks to steal credentials from employees with CDE access or directly from customers.
Sensitive Data Leaks: Any fragments of sensitive data, including compromised credentials, payment card numbers, or internal documents, found on the dark web, online forums, or other public data sources that originated from or could grant access to the CDE.
Vulnerabilities and Misconfigurations: Any security weaknesses or misconfigurations on external-facing assets that, if exploited, could provide a vector into the CDE. This includes outdated software, missing security headers, or insecure protocols.
The primary goal of understanding and managing the External CDE Footprint is to provide an "attacker-eye view" of potential entry points and vulnerabilities. By comprehensively mapping this footprint, organizations can proactively:
Accurately Scope PCI DSS: Ensure all relevant external assets are correctly identified and included in the scope of PCI DSS compliance, even those not initially recognized internally.
Identify Shadow IT and Unknown Assets: Discover unmanaged systems or applications that interact with CHD but are not formally tracked or secured by IT, posing significant risks.
Prioritize External Risk Remediation: Focus efforts on patching vulnerabilities and fixing misconfigurations on the most exposed assets that pose the highest risk to the CDE.
Enhance Threat Detection: Understand potential attack vectors to develop more effective monitoring and alert for suspicious activity from the external perimeter.
Strengthen Network Segmentation: Verify that external exposures do not inadvertently bypass or weaken existing CDE segmentation controls.
Managing the External CDE Footprint is a crucial, ongoing cybersecurity practice that helps organizations reduce their attack surface and protect payment card data from external threats.
ThreatNG, an all-in-one external attack surface management, digital risk protection, and security ratings solution, can significantly help organizations understand and manage their External CDE Footprint by providing an "outside-in" perspective of their digital presence related to cardholder data.
External Discovery & Continuous Monitoring
ThreatNG performs purely external, unauthenticated discovery, identifying assets and risks from an attacker's perspective without needing connectors. This is critical for understanding the External CDE Footprint, as it uncovers unknown or rogue assets that might be storing, processing, or transmitting cardholder data (CHD) and thus fall within PCI DSS scope. ThreatNG monitors an organization's external attack surface, digital risk, and security ratings. This ongoing monitoring ensures that new exposures or changes to existing assets that could impact the CDE's security are immediately identified and incorporated into the External CDE Footprint.
Examples of ThreatNG's help:
Identifying Undocumented Applications: ThreatNG can discover "Applications Identified" and login pages that the organization may not have formally tracked. If these applications handle CHD, their discovery is vital for understanding the External CDE Footprint, ensuring they are inventoried and secured according to PCI DSS Requirement 1.4.2. ThreatNG's continuous discovery helps ensure all such interfaces are known, tracked, and subject to proper security governance.
Detecting New Exposures from Misconfigurations: Through continuous monitoring, ThreatNG can identify newly exposed services on non-standard ports, as indicated by "Custom Port Scan" results or "Default Port Scan" findings. If these ports are open to services that could lead to the CDE, ThreatNG's immediate identification allows for proactive security measures, preventing potential entry points for attackers.
ThreatNG performs a variety of external assessments that directly contribute to understanding and managing the External CDE Footprint by highlighting potential attack vectors and data leakage points from an external perspective:
Cyber Risk Exposure: This assessment considers parameters like certificates, subdomain headers, vulnerabilities, and sensitive ports. It also factors in "Code Secret Exposure," which involves discovering code repositories and investigating their contents for sensitive data. These are all critical components for understanding external exposure that could lead to CDE compromise.
Example: ThreatNG detecting "Invalid Certificates" on a public-facing web application highlights a weakness in cryptographic protection. This contributes to understanding the External CDE Footprint by revealing a potential vulnerability that could be exploited for man-in-the-middle attacks, potentially affecting CHD in transit (PCI DSS 4.2.1).
Example: The discovery of "Private IPs Found" in public DNS reveals internal network architecture. ThreatNG identified this information, which can bypass network segmentation. It is a critical component of the External CDE Footprint as it exposes systems crucial for protecting cardholder data (PCI DSS 1.1.1).
Cloud and SaaS Exposure: ThreatNG evaluates sanctioned and unsanctioned cloud services and Software-as-a-Service (SaaS) solutions, including identifying "Open Exposed Cloud Buckets" of AWS, Microsoft Azure, and Google Cloud Platform. This is crucial for understanding the External CDE Footprint, as cloud environments are frequently used for storing or processing CHD, and unknown or misconfigured instances pose significant risk.
Example: ThreatNG discovering "Files in Open Cloud Buckets" directly highlights a data exposure risk that could include CHD. This finding immediately adds a critical, potentially overlooked, component to the External CDE Footprint that must be addressed per PCI DSS 3.1.1 (retain cardholder data only if required).
Mobile App Exposure: ThreatNG evaluates how exposed an organization's mobile apps are through discovery in marketplaces and by analyzing their content for "Access Credentials," "Security Credentials," and "Platform Specific ID” Mobile applications can directly interact with or expose CHD.
Example: ThreatNG identifying "Mobile Application Exposure Sensitive Information Found" means sensitive data, such as APIs or basic auth credentials, are present within mobile applications. This finding is critical for understanding the External CDE Footprint as it points to potential violations of PCI DSS requirements related to sensitive authentication data storage (PCI DSS 3.2).
Breach & Ransomware Susceptibility: This assessment considers exposed sensitive ports, private IPs, known vulnerabilities, compromised credentials, and ransomware events/gang activity. These findings directly inform the External CDE Footprint by identifying specific points of weakness and active threats that attackers could target to compromise the CDE.
Example: ThreatNG identifies "Ransomware events" associated with the organization and provides intelligence about active data availability and integrity threats. This directly contributes to understanding the External CDE Footprint, prompting immediate activation of incident response procedures (PCI DSS 12.10.5).
ThreatNG provides comprehensive reports, including an "Inventory" report, "Security Ratings," and "External GRC Assessment Mappings (eg, PCI DSS)". These reports are invaluable for building and maintaining a clear picture of the External CDE Footprint:
The Inventory report directly supports the ongoing cataloging of assets that are part of or linked to the CDE's external attack surface.
External GRC Assessment Mappings allow organizations to see how discovered external risks, like "Subdomains Missing Content Security Policy," align with specific PCI DSS requirements. This helps prioritize remediation efforts for exposures that most directly impact PCI DSS compliance and security, informing the management of the External CDE Footprint.
ThreatNG's core capability is "Continuous Monitoring of external attack surface, digital risk, and security ratings of all organizations". This is fundamental to managing the External CDE Footprint, as the external attack surface is dynamic. New assets can be deployed, configurations can change, or sensitive data can be inadvertently exposed. Continuous monitoring ensures that the External CDE Footprint remains current, providing real-time awareness of new components that fall into CDE scope or pose a risk to it.
ThreatNG's investigation modules provide detailed insights that are critical for populating and enriching the understanding of the External CDE Footprint:
Domain Intelligence: This module comprehensively overviews an organization's digital presence, including DNS Intelligence (Domain Record Analysis, Domain Name Permutations, Web3 Domains), Email Intelligence, WHOIS Intelligence, and Subdomain Intelligence.
Example: Through Subdomain Intelligence, ThreatNG can identify "APIs on Subdomains". If these APIs handle payment data, their discovery is vital for the External CDE Footprint, ensuring they are included in the CDE's security scope and subjected to secure coding practices (PCI DSS 6.5.1).
Example: When ThreatNG performs a "Default Port Scan" as part of its Subdomain Intelligence, it identifies externally exposed ports. Suppose sensitive ports like those for databases (e.g., SQL Server, MySQL) or remote access (e.g., RDP, SSH) are open externally. This indicates potential unauthorized access points that must be documented as part of the External CDE Footprint and secured with firewalls (PCI DSS 1.2.1).
Sensitive Code Exposure: This module discovers sensitive information within public code repositories.
Example: If ThreatNG finds "Code Secrets Found" such as API keys (e.g., Stripe API key) or cloud credentials (e.g., AWS Access Key ID Value) in a public repository, these represent potential backdoor access points to systems within or connected to the CDE. This provides critical data for the External CDE Footprint, demanding immediate credential revocation and secure development practices (PCI DSS 6.6).
Cloud and SaaS Exposure: ThreatNG discovers "Sanctioned Cloud Services," "Unsanctioned Cloud Services," "Cloud Service Impersonations," and "Open Exposed Cloud Buckets" across major providers.
Example: Discovering an "Open Exposed Cloud Bucket" through Cloud and SaaS Exposure directly reveals an unintended storage location that might contain CHD. This immediately becomes a critical piece of the External CDE Footprint, highlighting the need to restrict access based on need-to-know (PCI DSS 7.2.1) and ensure unreadable stored PAN (PCI DSS 3.4.1).
Intelligence Repositories (DarCache)
ThreatNG's continuously updated intelligence repositories provide vital context for enriching the understanding of the External CDE Footprint by providing threat context and vulnerability details:
Dark Web (DarCache Dark Web): This includes "Compromised Credentials (DarCache Rupture)" and "Ransomware Groups and Activities (DarCache Ransomware)".
Example: "DarCache Rupture" (Compromised Credentials) identifies leaked usernames and passwords. If these credentials belong to personnel with CDE access, this intelligence is critical for understanding the External CDE Footprint, as it indicates a direct pathway for unauthorized access (PCI DSS 8.3.1).
Vulnerabilities (DarCache Vulnerability): This includes NVD (DarCache NVD), EPSS (DarCache EPSS), KEV (DarCache KEV), and Verified Proof-of-Concept (PoC) Exploits (DarCache eXploit).
Example: "DarCache KEV" identifies "Vulnerabilities actively exploiting in the wild". Suppose ThreatNG detects an internet-facing asset (identified as part of the CDE's external footprint) with a KEV vulnerability. In that case, this intelligence immediately highlights an immediate, proven threat for the CDE, mandating rapid patching prioritization (PCI DSS 6.2.3). "DarCache eXploit" provides direct links to PoC exploits, enabling security teams to reproduce vulnerabilities and understand their real-world impact to develop effective mitigation strategies, enhancing the understanding of the External CDE Footprint.
Working with Complementary Solutions
ThreatNG's capabilities create powerful synergies when combined with other cybersecurity solutions, significantly enhancing an organization's efforts to manage its External CDE Footprint.
Configuration Management Databases (CMDBs): ThreatNG's external discovery directly feeds newly identified assets and misconfigurations into a CMDB.
Example: When ThreatNG identifies "Applications Identified" or "Private IPs Found" previously unknown to the organization, this data can be automatically populated into the CMDB. This ensures the CMDB, which serves as the core for tracking the CDE's components, is complete and accurate, aligning with PCI DSS Requirement 1.4.2 for maintaining an inventory of system components.
Vulnerability Management (VM) Platforms: ThreatNG's external assessment capabilities, particularly its identification of "Critical Severity Vulnerabilities Found" and "High Severity Vulnerabilities Found" on external subdomains, provide a crucial external perspective that complements VM platforms.
Example: ThreatNG can flag an exposed web application with a critical vulnerability. This External CDE Footprint insight can then be pushed to a VM platform to initiate deeper, authenticated scans of the application's internal components. This combined approach ensures that external and internal vulnerabilities that could expose the CDE are identified and prioritized for remediation, supporting PCI DSS 6.2.3 (addressing security vulnerabilities) and 11.3.1 (annual external penetration testing).
Cloud Security Posture Management (CSPM) Tools: ThreatNG's "Cloud and SaaS Exposure" capability identifies externally exposed cloud resources and misconfigurations.
Example: ThreatNG might discover an "Open Exposed Cloud Bucket" potentially containing CHD. This External CDE Footprint insight can trigger a more granular internal scan by a CSPM tool to confirm data presence, assess misconfigurations, and ensure access controls are aligned with PCI DSS 7.2.1 (restrict access based on need-to-know) and 3.4.1 (render stored PAN unreadable). The CSPM tool can then continuously monitor the cloud environment for new exposures, enriching the overall understanding of the External CDE Footprint.
Security Information and Event Management (SIEM) Systems: ThreatNG's findings from its various assessment modules can be integrated into a SIEM.
Example: Details about "Admin Page References" or "Custom Port Scan" results, revealing unexpected open ports on external interfaces, can be fed into the SIEM. The SIEM can then correlate these external insights with internal log data to detect suspicious access attempts or activities targeting these newly identified or unmanaged attack surface components, supporting PCI DSS 10.2.1 (logging access to system components) and 10.6.1 (monitoring and responding to security alerts).
