So your card acquirer or payment processor said you need to be compliant with Payment Card Industry Data Security Standard (PCI DSS). This standard breaks down into almost 300 requirements, and it is really hard to implement them all on every system in scope, so your first task is to shrink the scope as much as possible. For the rest of the systems - you’ll set up a bunch of various security controls, and there are lots of enterprise-grade software to cover all needs.
But what if we want to cut costs? I’ll share my experience of implementing these requirements using trusted open-source tools - it was verified by PCI Qualified Security Assessors at Amaiz, a UK-based neo-bank.
Requirement 1.1: Establish Firewall and Router Configurations Using Firewalld, you can define complex rules for network traffic, ensuring that only authorized connections to the cardholder data environment are permitted. Its granular control over configurations ensures Requirement 1.1 is comprehensively covered.
Requirement 3.4: Protect Stored Cardholder Data This requirement is covered by built-in OS tools like Cryptsetup (LUKS), which offers robust encryption for data at rest. It ensures that stored data is only accessible to authorized persons, thus keeping cardholder data secure from potential breaches.
Requirement 4.1: Use of Strong Cryptography for Data Transmission OpenSSL provides the libraries required to implement secure protocols such as TLS, shielding transmitted cardholder data over open, public networks - a core aspect of Requirement 4.1.
Requirement 5.1: Deploy Anti-Virus Software Addressing Requirement 5.1, ClamAV provides an open-source solution designed to detect malware, viruses, and other threats, ensuring systems commonly affected by such malicious software are adequately protected.
Requirement 6.2: Update System Components with Latest Vendor-Supplied Security Patches Osquery can be employed to proactively monitor your systems to ensure they are updated with the latest security patches. While not a patching tool itself, it can alert administrators to applicable updates for their systems, aligning with Requirement 6.2. It is also very useful as an MDM solution.
Requirement 7.1: Restrict Access to Cardholder Data FreeIPA can be used alongside LDAP configurations to manage user access, aligning with Requirement 7.1 by ensuring that access to system components and cardholder data is strictly controlled and regulated.
Requirement 8.2: Strong Authentication Measures For strong authentication, as outlined in Requirement 8.2, implementing FreeIPA can offer robust solutions for managing complex passwords and access control, employing authentication methods to safeguard data.
Requirement 10.2: Automated Audit Trails To fulfill the need for automated audit trails mentioned in Requirement 10.2, the Elasticsearch stack comes to mind first. It provides a powerful set of tools to collect, store, and visualize logs in real-time, facilitating effective tracking of all access to system components. But it's free version fails requirement 8.2, as it’s strong authentication measures are included in paid extension, so we’ll use it’s fork - OpenSearch which offers it all by default.
Requirement 11.4: Use Intrusion-Detection/Prevention Techniques The deployment of Snort as an intrusion detection and prevention system meets Requirement 11.4 by monitoring network traffic and alerting administrators to potential intrusions, thus protecting the network's perimeter and critical points within the cardholder data environment. And OSSEC does the required host-based intrusion detection.
Requirement 12.10: Incident Response Plan TheHive is an open-source, scalable, and easy-to-use incident response platform that can be implemented to meet Requirement 12.10, enabling organizations to swiftly respond to IT incidents and track crisis resolution.
In conclusion, open-source tools offer a solid foundation for establishing and maintaining PCI DSS compliance. However, it is crucial to note that while these tools are powerful and flexible, they require expert configuration and regular maintenance. Organizations should ensure they have the necessary skills and resources to deploy and manage these tools effectively. Furthermore, while many of the tools are freely available, investment into proper training and possibly support arrangements is advisable to realize their full potential in PCI DSS compliance efforts.