11.5.1.1
Defined Approach Requirements:
Additional requirement for service providers only: Intrusion-detection and/or intrusion-prevention techniques detect, alert on/prevent, and address covert malware communication channels.
Customized Approach Objective:
Mechanisms are in place to detect and alert/prevent covert communications with command-and-control systems. Alerts generated by these mechanisms are responded to by personnel, or by automated means that ensure that such communications are blocked.
Applicability Notes:
This requirement applies only when the entity being assessed is a service provider.
This requirement is a best practice until 31 March 2025, after which it will be required and must be fully considered during a PCI DSS assessment.
Defined Approach Testing Procedures:
- 11.5.1.1.a Additional testing procedure for service provider assessments only: Examine documentation and configuration settings to verify that methods to detect and alert on/prevent covert malware communication channels are in place and operating.
- 11.5.1.1.b Additional testing procedure for service provider assessments only: Examine the entity’s incident-response plan (Requirement 12.10.1) to verify it requires and defines a response in the event that covert malware communication channels are detected.
- 11.5.1.1.c Additional testing procedure for service provider assessments only: Interview responsible personnel and observe processes to verify that personnel maintain knowledge of covert malware communication and control techniques and are knowledgeable about how to respond when malware is suspected.
Purpose:
Detecting covert malware communication attempts (for example, DNS tunneling) can help block the spread of malware laterally inside a network and the exfiltration of data. When deciding where to place this control, entities should consider critical locations in the network, and likely routes for covert channels.
When malware establishes a foothold in an infected environment, it often tries to establish a communication channel to a command-andcontrol (C&C) server. Through the C&C server, the attacker communicates with and controls malware on compromised systems to deliver malicious payloads or instructions, or to initiate data exfiltration. In many cases, the malware will communicate with the C&C server indirectly via botnets, bypassing monitoring, blocking controls, and rendering these methods ineffective to detect the covert channels.
Good Practice:
Methods that can help detect and address malware communications channels include realtime endpoint scanning, egress traffic filtering, an ”allow” listing, data loss prevention tools, and network security monitoring tools such as IDS/IPS. Additionally, DNS queries and responses are a key data source used by network defenders in support of incident response as well as intrusion discovery. When these transactions are collected for processing and analytics, they can enable a number of valuable security analytic scenarios.
It is important that organizations maintain up-todate knowledge of malware modes of operation, as mitigating these can help detect and limit the impact of malware in the environment.
