Credit Union ATM Network Security

What ATM Networks Are

Credit union ATM networks consist of the machines members use, the communication infrastructure connecting them, and the backend systems that authorize transactions. A typical deployment includes:

ATM Hardware: Cash dispensers, card readers, PIN pads, receipt printers, deposit modules, and the embedded computer running ATM software

Network Infrastructure: Dedicated connections or VPN tunnels linking ATMs to your network, routing through switches and firewalls to reach authorization systems

Backend Systems: ATM controllers, switching software, connection to core banking, interface with card networks (STAR, NYCE, Allpoint), transaction processing and settlement systems

Shared Networks: For credit unions participating in CO-OP Network or other shared branching, connections to external authorization systems and surcharge-free network infrastructure

Each component introduces attack surface. ATMs sit in publicly accessible locations. Network connections traverse untrusted infrastructure. Backend systems bridge your secure network to external payment networks.

The Security Challenge

ATM networks face unique security problems:

Physical Access
ATMs sit in parking lots, convenience stores, and unsecured lobbies. Attackers have unlimited time to examine hardware, identify vulnerabilities, and install skimming devices or modify equipment. Physical security is the first line of defense—and the weakest.

Legacy Technology
Many ATMs still run Windows 7 or XP embedded systems that no longer receive security updates. The ATM software itself often hasn't been updated in years. Card readers use magnetic stripe technology that's inherently insecure. Upgrading is expensive, so vulnerabilities persist.

Network Exposure
ATM network traffic often travels over shared infrastructure. Connections to shared networks create trust relationships with external systems. Encryption is sometimes optional or poorly implemented. Network segmentation is inconsistent.

Regulatory Requirements
PCI DSS 4.0 includes specific requirements for ATM security. FFIEC expects physical security controls and network segmentation. NCUA examiners review ATM security during examinations, particularly for credit unions with large fleets or participation in shared networks.

Common ATM Security Vulnerabilities

Through ATM assessments across credit unions  we consistently find:

Compliance Considerations

Credit union ATM security directly impacts compliance with:

PCI DSS 4.0 — Requirement 9 addresses physical security for ATMs. Requirement 2.2.7 specifically covers hardening of ATM systems. Network segmentation requirements apply to ATM infrastructure. Regular vulnerability scanning is required.

FFIEC Guidance — The FFIEC IT Examination Handbook includes specific guidance on ATM security, covering physical controls, network architecture, and incident response. Examiners evaluate whether controls are appropriate to risk.

NCUA Part 748 Appendix A — Requires appropriate security controls for systems handling member information and transactions. This includes ATM networks, particularly authentication and authorization controls.

Card Network Rules — Visa, Mastercard, and shared networks have specific security requirements for ATM deployers. Non-compliance can result in fines or loss of network access.

Assessment Approach

Our ATM network assessments identify vulnerabilities across the entire infrastructure:

Physical Security Review — On-site inspection of ATM installations to evaluate physical security controls, tamper-evidence, anti-skimming measures, and surveillance coverage. We test physical access controls and document exposure risks.

Network Architecture Assessment — Evaluation of network segmentation, firewall rules, encryption implementation, and connection security. We map traffic flows from ATMs through your network to authorization systems and identify isolation failures.

Penetration Testing — Active testing of ATM network infrastructure, management interfaces, and backend systems. This includes authentication bypass attempts, privilege escalation testing, and exploitation of identified vulnerabilities.

Configuration Review — Analysis of ATM software configuration, operating system hardening, credential management, and security settings. We identify default configurations, weak passwords, and unnecessary services.

Transaction Security Testing — Review of authorization flows, settlement processes, and integration with core banking. We test for transaction manipulation opportunities and authorization bypass vulnerabilities.

Deliverables

Assessments include:

• Site-specific findings for each ATM location with photographic evidence
• Network architecture diagrams showing segmentation issues
• Prioritized remediation guidance based on risk and credit union resources
• PCI DSS and FFIEC compliance mapping
• Executive summary suitable for board presentation and examiner review
• Remediation roadmap with timeline and budget considerations

Testing Cadence

PCI DSS requires annual penetration testing and quarterly vulnerability scanning for environments handling card data. Many credit unions assess ATM networks annually, with interim reviews after network changes or ATM additions.

For credit unions with large ATM fleets, we can structure assessments to cover a representative sample annually with full fleet coverage over a multi-year cycle.