Public-Facing Payment Application Security
In cybersecurity, Public-Facing Payment Application Security refers to the specialized discipline of protecting web and mobile applications, as well as their underlying infrastructure, that are accessible from the internet and directly involved in handling, transmitting, or processing payment card data. This security focus is critical because these applications are often the primary entry point for attackers seeking to compromise sensitive financial information.
The scope of Public-Facing Payment Application Security extends beyond generic application security and specifically addresses the unique risks associated with payment card industry (PCI) data. It encompasses a range of proactive and continuous measures, including:
Secure Software Development Lifecycle (SSDLC): Integrating security considerations into every application development phase, from design and coding to testing, deployment, and maintenance. This involves secure coding practices, regular code reviews, and threat modeling to prevent vulnerabilities.
Vulnerability Management: Proactively identifying and remedying security flaws within the application code and its components. This includes:
Dynamic Application Security Testing (DAST): Black-box testing that simulates attacks on a running application.
Static Application Security Testing (SAST): White-box testing that analyzes source code for vulnerabilities without executing the application.
Interactive Application Security Testing (IAST): A hybrid approach combining elements of DAST and SAST, running within the application.
Software Composition Analysis (SCA): Identifying vulnerabilities in open-source and third-party components used within the application.
Penetration Testing: Ethical hacking simulations targeting the application from an external perspective to uncover exploitable weaknesses.
Protection Against Common Web Attacks: Implementing robust defenses against well-known attack vectors such as:
SQL Injection: Preventing malicious SQL queries from being injected into input fields to manipulate databases.
Cross-Site Scripting (XSS): Protecting against the injection of malicious scripts into web pages viewed by other users.
Broken Authentication and Session Management: Ensuring secure handling of user identities and session tokens to prevent unauthorized access.
Insecure Deserialization, Server-Side Request Forgery (SSRF), XML External Entities (XXE): Defending against these complex vulnerabilities that can lead to remote code execution or data exposure.
Payment Data Protection: Ensuring that sensitive payment card data is never stored in plaintext within the application or its associated systems (e.g., logs, databases) and that strong encryption is used for data in transit and at rest. This also includes adherence to PCI DSS rules prohibiting storing sensitive authentication data (CVV, PIN).
Input Validation and Output Encoding: Rigorously validate all user input to prevent malicious data from entering the application and properly encode all output to avoid injection attacks.
Web Application Firewalls (WAFs): Deploying WAFs as a protective layer in front of payment applications to detect and block malicious traffic and attacks, serving as a virtual patch for specific vulnerabilities.
Secure API Design and Management: Protecting APIs that handle payment data through strong authentication, authorization, rate limiting, and input validation.
Configuration Hardening: Ensuring that web servers, application servers, databases, and operating systems supporting the payment application are securely configured, with unnecessary services disabled and default credentials changed.
Error Handling and Logging: Implementing secure error handling that avoids revealing sensitive information to attackers, and maintaining comprehensive, secure audit logs for all application activity.
The ultimate goal of Public-Facing Payment Application Security is to create a robust, resilient barrier against attacks, thereby safeguarding sensitive payment card data and ensuring continuous compliance with PCI DSS requirements.
ThreatNG, an all-in-one external attack surface management, digital risk protection, and security ratings solution, can significantly help organizations ensure Public-Facing Payment Application Security by providing a continuous, attacker-eye view of their external applications and related infrastructure.
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 Public-Facing Payment Application Security because it uncovers unknown or rogue web and mobile applications that might be storing, processing, or transmitting cardholder data (CHD). ThreatNG monitors an organization's external attack surface, digital risk, and security ratings. This ongoing monitoring ensures that new exposures or changes to existing applications that could impact CHD security are immediately identified, providing real-time visibility into the security posture of public-facing payment applications.
Examples of ThreatNG's help:
Identifying Undocumented Payment 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 Public-Facing Payment Application Security, ensuring they are inventoried and secured according to PCI DSS Requirement 1.4.2 (maintaining an inventory of system components in scope). 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. This directly relates to PCI DSS Requirement 1.1.6 (restricting traffic to necessary ports).
ThreatNG performs a variety of external assessments that directly contribute to Public-Facing Payment Application Security by highlighting potential attack vectors and data leakage points from an external perspective:
Web Application Hijack Susceptibility: ThreatNG analyzes the external attack surface of web applications, including Domain Intelligence, to identify potential entry points for attackers. This directly supports PCI DSS Requirement 6.4.3, which mandates protections for public-facing web applications against attacks.
Example: If ThreatNG identifies "Subdomains Missing Content Security Policy", it signals a vulnerability that attackers could use for Cross-Site Scripting (XSS) or other injection attacks. Proactively addressing this finding, often discovered during vulnerability scans or penetration tests (PCI DSS 11.3.1), directly enhances Public-Facing Payment Application Security by reducing the web application attack surface.
Mobile App Exposure: ThreatNG evaluates an organization's mobile app exposure through discovery in marketplaces and by analyzing its content for "Access Credentials," "Security Credentials," and "Platform Specific Id.” Mobile applications that handle payments represent critical public-facing components.
Example: ThreatNG identifying "Mobile Application Exposure Sensitive Information Found" means sensitive data, such as "Amazon AWS Access Key ID" or "APIs", is present within mobile applications. This finding is critical for Public-Facing Payment Application Security as it points to potential violations of PCI DSS requirements related to not storing sensitive authentication data after authorization (PCI DSS 3.2) and secure data storage (PCI DSS 3.4).
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 the presence of sensitive data. These are all critical components for understanding external exposure that could lead to CDE compromise through public-facing applications.
Example: ThreatNG detecting "Invalid Certificates" on a public-facing web application highlights a weakness in cryptographic protection (PCI DSS 4.2.1). Proactively updating these certificates removes an avenue for man-in-the-middle attacks, which can compromise data sent to public-facing payment applications.
Example: The discovery of "Private IPs Found" in public DNS reveals internal network architecture. ThreatNG identified this information, which can bypass network segmentation. This makes it a critical component for Public-Facing Payment Application Security as it exposes systems crucial for protecting cardholder data.
Web Application Firewalls (WAFs) Missing: ThreatNG explicitly identifies when "Web Application Firewalls (WAFs) Missing" on subdomains. The absence of a WAF means public-facing web applications are more exposed to vulnerabilities (PCI DSS 6.6), and intrusion detection/prevention systems may be inadequate (PCI DSS 11.4).
Example: ThreatNG reporting "Web Application Firewalls (WAFs) Missing" on a subdomain directly indicates a critical gap in protecting public-facing web applications (PCI DSS 6.6) and a weakness in intrusion prevention capabilities (PCI DSS 11.4). Proactively deploying a WAF significantly enhances Public-Facing Payment Application Security.
ThreatNG provides comprehensive reports, including "Prioritized (High, Medium, Low, and Informational)" reports, "Security Ratings", and "External GRC Assessment Mappings (eg, PCI DSS)". These reports are invaluable for informing and driving Public-Facing Payment Application Security efforts:
The Prioritized reports help organizations focus on the most critical external risks, including those specific to public-facing payment applications, allowing them to allocate resources effectively.
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 directly impact CHD security in payment applications.
ThreatNG's core capability is "Continuous Monitoring of external attack surface, digital risk, and security ratings of all organizations". This is fundamental to Public-Facing Payment Application Security, as the attack surface of these applications is dynamic. New features, integrations, or misconfigurations can introduce vulnerabilities at any time. Continuous monitoring ensures that new potential attack vectors specific to payment applications are identified as soon as they appear, providing real-time awareness and allowing for prompt, proactive security.
ThreatNG's investigation modules provide detailed insights that are critical for identifying and understanding the components of Public-Facing Payment Application Security that need to be addressed:
Domain Intelligence: This module provides a comprehensive overview of an organization's digital presence, including DNS Intelligence, 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 Public-Facing Payment Application Security, ensuring they are included in the CDE's security scope and subjected to secure coding practices (PCI DSS 6.5.1).
Example: ThreatNG identifying "Subdomains with No Automatic HTTPS Redirect" or "Subdomains Missing Strict Transport Security (HSTS) Header" indicates data-in-transit vulnerabilities. These issues create a weaker security posture for public-facing payment applications as unencrypted HTTP connections could expose CHD during transmission (PCI DSS 4.2.1.1).
Sensitive Code Exposure: This module discovers public code repositories and uncovers digital risks, including "Access Credentials" (like API Keys, Access Tokens, and Cloud Credentials) and "Security Credentials" (like Cryptographic Keys).
Example: If ThreatNG finds "Code Secrets Found" such as a "Stripe API key" or "PayPal Braintree Access Token" in a public repository, these represent direct avenues for attack on payment applications. Proactively revoking these credentials and implementing secure development practices reduces a critical attack surface vector (PCI DSS 6.6).
Mobile Application Discovery: ThreatNG discovers mobile apps related to the organization within marketplaces and analyzes their content for sensitive credentials and platform-specific identifiers.
Example: ThreatNG identifying "Access Credentials" like "Stripe API Key" or "PayPal Braintree Access Token" directly within a discovered mobile app signals a critical exposure. Proactively addressing these findings enhances Public-Facing Payment Application Security and helps meet PCI DSS 3.2 (not storing sensitive authentication data).
Intelligence Repositories (DarCache)
ThreatNG's continuously updated intelligence repositories provide vital context for informing Public-Facing Payment Application Security efforts by providing threat context and vulnerability details.
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". If ThreatNG detects a public-facing payment application with a KEV vulnerability, proactively patching this immediately reduces a critical part of the attack surface (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 Public-Facing Payment Application Security.
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 are for a public-facing payment application, proactively forcing password resets and enforcing MFA reduces the attack surface by negating the value of these leaked credentials (PCI DSS 8.3.1).
Working with Complementary Solutions
ThreatNG's capabilities create powerful synergies when combined with other cybersecurity solutions, significantly enhancing an organization's efforts to achieve Public-Facing Payment Application Security.
Web Application Firewalls (WAFs): ThreatNG's assessments related to web application security, such as identifying "Subdomains Missing Content Security Policy" or "Subdomains Missing X-Content-Type Header", provide actionable intelligence for WAF configuration.
Example: If ThreatNG flags missing security headers on a public-facing payment application, this insight can be pushed to a WAF to implement those headers or to block traffic attempting to exploit such weaknesses. This combined approach strengthens application security, serving as a proactive layer of defense for PCI DSS 6.6 (secure web applications).
Dynamic Application Security Testing (DAST) / Static Application Security Testing (SAST) Tools: ThreatNG's external discovery of payment applications and its identification of "Code Secret Exposure" or "Errors on Subdomains" provide valuable context for DAST/SAST tools.
Example: When ThreatNG identifies an "API on Subdomains" or "Assets with PHP" that are part of a payment application, this discovery can trigger more granular DAST or SAST scans on these components. This ensures a deeper analysis of the application's code and runtime behavior, helping to find vulnerabilities that impact PCI DSS 6.5.1 (secure coding practices).
Security Information and Event Management (SIEM) Systems: ThreatNG's findings from its various assessment modules related to public-facing payment applications 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 application logs (PCI DSS 10.2.1) to detect suspicious access attempts or attacks targeting the payment application, supporting PCI DSS 10.6.1 (monitoring and responding to security alerts).
Content Delivery Networks (CDNs) / Edge Security Platforms: ThreatNG's identification of issues like "Subdomains with No Automatic HTTPS Redirect" or "Subdomains Missing Strict Transport Security (HSTS) Header" are critical for edge security.
Example: This insight can be provided to a CDN or edge security platform to enforce HTTPS redirection and HSTS headers at the network edge. This proactively secures data in transit for public-facing payment applications (PCI DSS 4.2.1.1).
