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1.1: All security policies and operational procedures that are identified in Requirement 1 are: (a) Documented, (b) Kept up to date, (c) In use, (d) Known to all affected parties.
  • Examine documentation and interview personnel to verify that security policies and operational procedures identified in Requirement 1 are managed in accordance with all elements specified in this requirement.
Description

Requirement 1.1.1

Purpose

Requirement 1.1.1 is about effectively managing and maintaining the various policies and procedures specified throughout Requirement 1. While it is important to define the specific policies or procedures called out in Requirement 1, it is equally important to ensure they are properly documented, maintained, and disseminated.

Good Practice

It is important to update policies and procedures as needed to address changes in processes, technologies, and business objectives. For these reasons, consider updating these documents as soon as possible after a change occurs and not only on a periodic cycle.

Definitions

Security policies define the entity’s security objectives and principles. Operational procedures describe how to perform activities, and define the controls, methods, and processes that are followed to achieve the desired result in a consistent manner and in accordance with policy objectives.

Requirement 1.1.2

Purpose

If roles and responsibilities are not formally assigned, personnel may not be aware of their day-to-day responsibilities and critical activities may not occur.

Good Practice

Roles and responsibilities may be documented within policies and procedures or maintained within separate documents. As part of communicating roles and responsibilities, entities can consider having personnel acknowledge their acceptance and understanding of their assigned roles and responsibilities.

Examples

A method to document roles and responsibilities is a responsibility assignment matrix that includes who is responsible, accountable, consulted, and informed (also called a RACI matrix).

1.1: Roles and responsibilities for performing activities in Requirement 1 are documented, assigned, and understood.
  • Examine documentation to verify that descriptions of roles and responsibilities for performing activities in Requirement 1 are documented and assigned.
  • Interview personnel responsible for performing activities in Requirement 1 to verify that roles and responsibilities are assigned as documented and are understood.
Description

Requirement 1.1.1

Purpose

Requirement 1.1.1 is about effectively managing and maintaining the various policies and procedures specified throughout Requirement 1. While it is important to define the specific policies or procedures called out in Requirement 1, it is equally important to ensure they are properly documented, maintained, and disseminated.

Good Practice

It is important to update policies and procedures as needed to address changes in processes, technologies, and business objectives. For these reasons, consider updating these documents as soon as possible after a change occurs and not only on a periodic cycle.

Definitions

Security policies define the entity’s security objectives and principles. Operational procedures describe how to perform activities, and define the controls, methods, and processes that are followed to achieve the desired result in a consistent manner and in accordance with policy objectives.

Requirement 1.1.2

Purpose

If roles and responsibilities are not formally assigned, personnel may not be aware of their day-to-day responsibilities and critical activities may not occur.

Good Practice

Roles and responsibilities may be documented within policies and procedures or maintained within separate documents. As part of communicating roles and responsibilities, entities can consider having personnel acknowledge their acceptance and understanding of their assigned roles and responsibilities.

Examples

A method to document roles and responsibilities is a responsibility assignment matrix that includes who is responsible, accountable, consulted, and informed (also called a RACI matrix).

1.2: Configuration standards for NSC rulesets are: (a) Defined, (b) Implemented, (c) Maintained.
  • Examine the configuration standards for NSC rulesets to verify the standards are in accordance with all elements specified in this requirement.
  • Examine configuration settings for NSC rulesets to verify that rulesets are implemented according to the configuration standards.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: All changes to network connections and to configurations of NSCs are approved and managed in accordance with the change control process defined at Requirement 6.5.1.
  • Examine documented procedures to verify that changes to network connections and configurations of NSCs are included in the formal change control process in accordance with Requirement 6.5.1.
  • Examine network configuration settings to identify changes made to network connections. Interview responsible personnel and examine change control records to verify that identified changes to network connections were approved and managed in accordance with Requirement 6.5.1.
  • Examine network configuration settings to identify changes made to configurations of NSCs. Interview responsible personnel and examine change control records to verify that identified changes to configurations of NSCs were approved and managed in accordance with Requirement 6.5.1.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: An accurate network diagram(s) is maintained that shows all connections between the CDE and other networks, including any wireless networks.
  • Examine diagram(s) and network configurations to verify that an accurate network diagram(s) exists in accordance with all elements specified in this requirement.
  • Examine documentation and interview responsible personnel to verify that the network diagram(s) is accurate and updated when there are changes to the environment.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: An accurate data-flow diagram(s) is maintained that meets the following: (a) Shows all account data flows across systems and networks, (b) Updated as needed upon changes to the environment.
  • Examine data-flow diagram(s) and interview personnel to verify the diagram(s) show all account data flows in accordance with all elements specified in this requirement.
  • Examine documentation and interview responsible personnel to verify that the data-flow diagram(s) is accurate and updated when there are changes to the environment.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: All services, protocols, and ports allowed are identified, approved, and have a defined business need.
  • Examine documentation to verify that a list exists of all allowed services, protocols, and ports, including business justification and approval for each.
  • Examine configuration settings for NSCs to verify that only approved services, protocols, and ports are in use.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: Security features are defined and implemented for all services, protocols, and ports that are in use and considered to be insecure, such that the risk is mitigated.
  • Examine documentation that identifies all insecure services, protocols, and ports in use to verify that for each, security features are defined to mitigate the risk.
  • Examine configuration settings for NSCs to verify that the defined security features are implemented for each identified insecure service, protocol, and port.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: Configurations of NSCs are reviewed at least once every six months to confirm they are relevant and effective.
  • Examine documentation to verify procedures are defined for reviewing configurations of NSCs at least once every six months.
  • Examine documentation of reviews of configurations for NSCs and interview responsible personnel to verify that reviews occur at least once every six months.
  • Examine configurations for NSCs to verify that configurations identified as no longer being supported by a business justification are removed or updated.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.2: Configuration files for NSCs are: (a) Secured from unauthorized access, (b) Kept consistent with active network configurations.
  • Examine configuration files for NSCs to verify they are in accordance with all elements specified in this requirement.
Description

Requirement 1.2.1

Purpose

Configuration standards for NSC rulesets help ensure that the baseline security of network components is consistently applied and maintained. Without defined standards, configurations may be inconsistent and leave vulnerabilities that could be exploited.

Good Practice

Configuration standards should be reviewed and updated as part of the organization's change management process. Standards should address all NSCs, including firewalls, routers, and cloud security groups.

Definitions

NSC rulesets are the configuration settings that define what traffic is allowed or denied by network security controls such as firewalls, routers, and cloud security groups.

Requirement 1.2.2

Purpose

Unauthorized or unapproved changes to network connections or NSC configurations can create vulnerabilities and expose cardholder data. Managing changes through an established change control process helps ensure the security of the network is maintained.

Good Practice

Changes should be documented and approved before implementation. The change control process defined at Requirement 6.5.1 should be leveraged for all changes to network connections and NSC configurations.

Requirement 1.2.3

Purpose

An accurate, up-to-date network diagram helps organizations understand their network architecture and the connections between the CDE and other networks. Without this understanding, configurations may be missed that could leave the CDE vulnerable to unauthorized access.

Good Practice

Network diagrams should be updated whenever there are changes to the network environment. Diagrams should clearly identify all connections to the CDE, including wireless networks, and should be reviewed periodically to ensure accuracy.

Examples

Network diagrams may include topology diagrams showing the physical and logical layout of the network, data flow diagrams, and firewall ruleset documentation.

Requirement 1.2.4

Purpose

Accurate data-flow diagrams help organizations understand and keep track of how account data flows across systems and networks. This knowledge is critical for implementing appropriate security controls and for identifying where account data may be at risk.

Good Practice

Data-flow diagrams should be updated as changes occur to the environment. Diagrams should show all flows of account data, including authorization, capture, settlement, chargeback, and refund flows.

Requirement 1.2.5

Purpose

Allowing unnecessary or unidentified services, protocols, or ports creates additional attack vectors. Identifying and approving only those that have a legitimate business need reduces the attack surface and helps ensure that unauthorized services are not inadvertently enabled.

Good Practice

All allowed services, protocols, and ports should be documented with the associated business justification. Protocols and ports that are not needed should be explicitly denied in NSC rulesets.

Requirement 1.2.6

Purpose

Services, protocols, and ports that are considered insecure can provide opportunities for malicious individuals to gain unauthorized access. Defining and implementing security features to mitigate the risks associated with insecure services reduces exposure.

Good Practice

Where insecure services cannot be avoided, compensating security features such as encryption or additional authentication should be implemented to reduce the risk. The risk associated with each insecure service should be documented and accepted by management.

Examples

Examples of insecure services include FTP, Telnet, and early versions of SSL/TLS. Security features to mitigate risk include encrypting the data channel or wrapping the insecure protocol in an encrypted tunnel.

Requirement 1.2.7

Purpose

NSC configurations can become outdated over time as business requirements change, technologies evolve, or new vulnerabilities are discovered. Periodic reviews help ensure that configurations remain relevant and effective in protecting the CDE.

Good Practice

Reviews should confirm that all rules are still needed, that temporary rules have been removed, and that configurations align with current business requirements. Reviews should be performed at least every six months and documented.

Requirement 1.2.8

Purpose

Configuration files for NSCs contain sensitive information about the network security architecture. If these files are not properly secured, unauthorized individuals could gain access to this information and use it to compromise the network.

Good Practice

Access to configuration files should be restricted to authorized personnel only. Running configurations should be synchronized with startup configurations to ensure consistency. Configuration files should be stored securely and backed up regularly.

1.3: Inbound traffic to the CDE is restricted as follows: (a) To only traffic that is necessary, (b) All other traffic is specifically denied.
  • Examine configuration standards for NSCs to verify that they define restricting inbound traffic to the CDE is in accordance with all elements specified in this requirement.
  • Examine configurations of NSCs to verify that inbound traffic to the CDE is restricted in accordance with all elements specified in this requirement.
Description

Requirement 1.3.1

Purpose

Restricting inbound traffic to the CDE to only necessary communications helps ensure that unauthorized or malicious traffic cannot reach systems that store, process, or transmit cardholder data. Without such restrictions, the CDE may be exposed to attacks from external or untrusted sources.

Good Practice

NSC rulesets should explicitly define what traffic is allowed into the CDE and deny all other traffic by default. Rules should be based on the principle of least privilege, allowing only the minimum necessary traffic.

Requirement 1.3.2

Purpose

Restricting outbound traffic from the CDE helps prevent data exfiltration and limits the ability of attackers to communicate with external command-and-control servers. Unauthorized outbound connections from the CDE may indicate that systems have been compromised.

Good Practice

Outbound traffic should be limited to only what is necessary for business operations, such as payment processing. All other outbound traffic should be denied by default. Egress filtering should be implemented at the network perimeter.

Requirement 1.3.3

Purpose

Wireless networks present unique security risks because the wireless signal can extend beyond the physical boundaries of the organization. NSCs between wireless networks and the CDE help ensure that wireless traffic is properly controlled and that unauthorized wireless access to the CDE is prevented.

Good Practice

All wireless traffic into the CDE should be denied by default, with specific rules allowing only authorized and necessary traffic. Wireless networks should be treated as untrusted networks regardless of whether they are within the organization's physical perimeter.

1.3: Outbound traffic from the CDE is restricted as follows: (a) To only traffic that is necessary, (b) All other traffic is specifically denied.
  • Examine configuration standards for NSCs to verify that they define restricting outbound traffic from the CDE in accordance with all elements specified in this requirement.
  • Examine configurations of NSCs to verify that outbound traffic from the CDE is restricted in accordance with all elements specified in this requirement.
Description

Requirement 1.3.1

Purpose

Restricting inbound traffic to the CDE to only necessary communications helps ensure that unauthorized or malicious traffic cannot reach systems that store, process, or transmit cardholder data. Without such restrictions, the CDE may be exposed to attacks from external or untrusted sources.

Good Practice

NSC rulesets should explicitly define what traffic is allowed into the CDE and deny all other traffic by default. Rules should be based on the principle of least privilege, allowing only the minimum necessary traffic.

Requirement 1.3.2

Purpose

Restricting outbound traffic from the CDE helps prevent data exfiltration and limits the ability of attackers to communicate with external command-and-control servers. Unauthorized outbound connections from the CDE may indicate that systems have been compromised.

Good Practice

Outbound traffic should be limited to only what is necessary for business operations, such as payment processing. All other outbound traffic should be denied by default. Egress filtering should be implemented at the network perimeter.

Requirement 1.3.3

Purpose

Wireless networks present unique security risks because the wireless signal can extend beyond the physical boundaries of the organization. NSCs between wireless networks and the CDE help ensure that wireless traffic is properly controlled and that unauthorized wireless access to the CDE is prevented.

Good Practice

All wireless traffic into the CDE should be denied by default, with specific rules allowing only authorized and necessary traffic. Wireless networks should be treated as untrusted networks regardless of whether they are within the organization's physical perimeter.

1.3: NSCs are installed between all wireless networks and the CDE, regardless of whether the wireless network is a CDE, such that: (a) All wireless traffic from wireless networks into the CDE is denied by default, (b) Only wireless traffic with an authorized business purpose is allowed into the CDE.
  • Examine configuration settings and network diagrams to verify that NSCs are implemented between all wireless networks and the CDE, in accordance with all elements specified in this requirement.
Description

Requirement 1.3.1

Purpose

Restricting inbound traffic to the CDE to only necessary communications helps ensure that unauthorized or malicious traffic cannot reach systems that store, process, or transmit cardholder data. Without such restrictions, the CDE may be exposed to attacks from external or untrusted sources.

Good Practice

NSC rulesets should explicitly define what traffic is allowed into the CDE and deny all other traffic by default. Rules should be based on the principle of least privilege, allowing only the minimum necessary traffic.

Requirement 1.3.2

Purpose

Restricting outbound traffic from the CDE helps prevent data exfiltration and limits the ability of attackers to communicate with external command-and-control servers. Unauthorized outbound connections from the CDE may indicate that systems have been compromised.

Good Practice

Outbound traffic should be limited to only what is necessary for business operations, such as payment processing. All other outbound traffic should be denied by default. Egress filtering should be implemented at the network perimeter.

Requirement 1.3.3

Purpose

Wireless networks present unique security risks because the wireless signal can extend beyond the physical boundaries of the organization. NSCs between wireless networks and the CDE help ensure that wireless traffic is properly controlled and that unauthorized wireless access to the CDE is prevented.

Good Practice

All wireless traffic into the CDE should be denied by default, with specific rules allowing only authorized and necessary traffic. Wireless networks should be treated as untrusted networks regardless of whether they are within the organization's physical perimeter.

1.4: NSCs are implemented between trusted and untrusted networks.
  • Examine configuration standards and network diagrams to verify that NSCs are defined between trusted and untrusted networks.
  • Examine network configurations to verify that NSCs are in place between trusted and untrusted networks, in accordance with the documented configuration standards and network diagrams.
Description

Requirement 1.4.1

Purpose

NSCs between trusted and untrusted networks are essential for controlling the flow of traffic and preventing unauthorized access. Without these controls, untrusted networks could directly access systems and data in trusted network segments.

Good Practice

NSCs should be placed at all connection points between trusted and untrusted networks. This includes connections to the Internet, partner networks, and other external networks. The NSCs should enforce policies that restrict traffic to only what is necessary.

Requirement 1.4.2

Purpose

Restricting inbound traffic from untrusted networks helps prevent unauthorized access and reduces the risk of attacks against systems in trusted network segments. Allowing only necessary traffic minimizes the attack surface.

Good Practice

Inbound traffic from untrusted networks should be limited to communications with system components that are authorized to provide publicly accessible services, protocols, and ports. All other inbound traffic should be denied.

Definitions

Untrusted networks include any network that is external to the networks belonging to the entity under review, or that is out of the entity's ability to control or manage.

Requirement 1.4.3

Purpose

Anti-spoofing measures help prevent attackers from using forged source IP addresses to bypass network security controls. Without these measures, traffic from untrusted networks could appear to originate from trusted internal networks.

Good Practice

NSCs should be configured to detect and block traffic with spoofed source addresses. This includes implementing ingress filtering to verify that source addresses are valid and egress filtering to prevent internal addresses from leaving the network.

Requirement 1.4.4

Purpose

System components that store cardholder data should not be directly accessible from untrusted networks. Placing these components in an internal network zone behind a DMZ or other security controls helps protect them from direct attack.

Good Practice

Systems that store cardholder data should be placed in internal network zones that are not directly accessible from the Internet or other untrusted networks. Access to these systems should be mediated through proxy servers, application firewalls, or other security controls.

Requirement 1.4.5

Purpose

Disclosing internal IP addresses and routing information to external parties can provide attackers with valuable information about the internal network topology, making it easier to target specific systems. Restricting disclosure of this information helps maintain the confidentiality of the network architecture.

Good Practice

Techniques such as Network Address Translation (NAT), placing systems behind proxy servers, and using private IP address spaces help prevent the disclosure of internal addressing information. Only authorized individuals should have access to internal routing information.

1.4: Inbound traffic from untrusted networks to trusted networks is restricted to: (a) Communications with system components that are authorized to provide publicly accessible services, protocols, and ports, (b) Stateful responses to communications initiated by system components in a trusted network, (c) All other traffic is denied.
  • Examine vendor documentation and configurations of NSCs to verify that inbound traffic from untrusted networks to trusted networks is restricted in accordance with all elements specified in this requirement.
Description

Requirement 1.4.1

Purpose

NSCs between trusted and untrusted networks are essential for controlling the flow of traffic and preventing unauthorized access. Without these controls, untrusted networks could directly access systems and data in trusted network segments.

Good Practice

NSCs should be placed at all connection points between trusted and untrusted networks. This includes connections to the Internet, partner networks, and other external networks. The NSCs should enforce policies that restrict traffic to only what is necessary.

Requirement 1.4.2

Purpose

Restricting inbound traffic from untrusted networks helps prevent unauthorized access and reduces the risk of attacks against systems in trusted network segments. Allowing only necessary traffic minimizes the attack surface.

Good Practice

Inbound traffic from untrusted networks should be limited to communications with system components that are authorized to provide publicly accessible services, protocols, and ports. All other inbound traffic should be denied.

Definitions

Untrusted networks include any network that is external to the networks belonging to the entity under review, or that is out of the entity's ability to control or manage.

Requirement 1.4.3

Purpose

Anti-spoofing measures help prevent attackers from using forged source IP addresses to bypass network security controls. Without these measures, traffic from untrusted networks could appear to originate from trusted internal networks.

Good Practice

NSCs should be configured to detect and block traffic with spoofed source addresses. This includes implementing ingress filtering to verify that source addresses are valid and egress filtering to prevent internal addresses from leaving the network.

Requirement 1.4.4

Purpose

System components that store cardholder data should not be directly accessible from untrusted networks. Placing these components in an internal network zone behind a DMZ or other security controls helps protect them from direct attack.

Good Practice

Systems that store cardholder data should be placed in internal network zones that are not directly accessible from the Internet or other untrusted networks. Access to these systems should be mediated through proxy servers, application firewalls, or other security controls.

Requirement 1.4.5

Purpose

Disclosing internal IP addresses and routing information to external parties can provide attackers with valuable information about the internal network topology, making it easier to target specific systems. Restricting disclosure of this information helps maintain the confidentiality of the network architecture.

Good Practice

Techniques such as Network Address Translation (NAT), placing systems behind proxy servers, and using private IP address spaces help prevent the disclosure of internal addressing information. Only authorized individuals should have access to internal routing information.

1.4: Anti-spoofing measures are implemented to detect and block forged source IP addresses from entering the trusted network.
  • Examine vendor documentation and configurations for NSCs to verify that anti-spoofing measures are implemented to detect and block forged source IP addresses from entering the trusted network.
Description

Requirement 1.4.1

Purpose

NSCs between trusted and untrusted networks are essential for controlling the flow of traffic and preventing unauthorized access. Without these controls, untrusted networks could directly access systems and data in trusted network segments.

Good Practice

NSCs should be placed at all connection points between trusted and untrusted networks. This includes connections to the Internet, partner networks, and other external networks. The NSCs should enforce policies that restrict traffic to only what is necessary.

Requirement 1.4.2

Purpose

Restricting inbound traffic from untrusted networks helps prevent unauthorized access and reduces the risk of attacks against systems in trusted network segments. Allowing only necessary traffic minimizes the attack surface.

Good Practice

Inbound traffic from untrusted networks should be limited to communications with system components that are authorized to provide publicly accessible services, protocols, and ports. All other inbound traffic should be denied.

Definitions

Untrusted networks include any network that is external to the networks belonging to the entity under review, or that is out of the entity's ability to control or manage.

Requirement 1.4.3

Purpose

Anti-spoofing measures help prevent attackers from using forged source IP addresses to bypass network security controls. Without these measures, traffic from untrusted networks could appear to originate from trusted internal networks.

Good Practice

NSCs should be configured to detect and block traffic with spoofed source addresses. This includes implementing ingress filtering to verify that source addresses are valid and egress filtering to prevent internal addresses from leaving the network.

Requirement 1.4.4

Purpose

System components that store cardholder data should not be directly accessible from untrusted networks. Placing these components in an internal network zone behind a DMZ or other security controls helps protect them from direct attack.

Good Practice

Systems that store cardholder data should be placed in internal network zones that are not directly accessible from the Internet or other untrusted networks. Access to these systems should be mediated through proxy servers, application firewalls, or other security controls.

Requirement 1.4.5

Purpose

Disclosing internal IP addresses and routing information to external parties can provide attackers with valuable information about the internal network topology, making it easier to target specific systems. Restricting disclosure of this information helps maintain the confidentiality of the network architecture.

Good Practice

Techniques such as Network Address Translation (NAT), placing systems behind proxy servers, and using private IP address spaces help prevent the disclosure of internal addressing information. Only authorized individuals should have access to internal routing information.

1.4: System components that store cardholder data are not directly accessible from untrusted networks.
  • Examine the data-flow diagram and network diagram to verify that it is documented that system components storing cardholder data are not directly accessible from the untrusted networks.
  • Examine configurations of NSCs to verify that controls are implemented such that system components storing cardholder data are not directly accessible from untrusted networks.
Description

Requirement 1.4.1

Purpose

NSCs between trusted and untrusted networks are essential for controlling the flow of traffic and preventing unauthorized access. Without these controls, untrusted networks could directly access systems and data in trusted network segments.

Good Practice

NSCs should be placed at all connection points between trusted and untrusted networks. This includes connections to the Internet, partner networks, and other external networks. The NSCs should enforce policies that restrict traffic to only what is necessary.

Requirement 1.4.2

Purpose

Restricting inbound traffic from untrusted networks helps prevent unauthorized access and reduces the risk of attacks against systems in trusted network segments. Allowing only necessary traffic minimizes the attack surface.

Good Practice

Inbound traffic from untrusted networks should be limited to communications with system components that are authorized to provide publicly accessible services, protocols, and ports. All other inbound traffic should be denied.

Definitions

Untrusted networks include any network that is external to the networks belonging to the entity under review, or that is out of the entity's ability to control or manage.

Requirement 1.4.3

Purpose

Anti-spoofing measures help prevent attackers from using forged source IP addresses to bypass network security controls. Without these measures, traffic from untrusted networks could appear to originate from trusted internal networks.

Good Practice

NSCs should be configured to detect and block traffic with spoofed source addresses. This includes implementing ingress filtering to verify that source addresses are valid and egress filtering to prevent internal addresses from leaving the network.

Requirement 1.4.4

Purpose

System components that store cardholder data should not be directly accessible from untrusted networks. Placing these components in an internal network zone behind a DMZ or other security controls helps protect them from direct attack.

Good Practice

Systems that store cardholder data should be placed in internal network zones that are not directly accessible from the Internet or other untrusted networks. Access to these systems should be mediated through proxy servers, application firewalls, or other security controls.

Requirement 1.4.5

Purpose

Disclosing internal IP addresses and routing information to external parties can provide attackers with valuable information about the internal network topology, making it easier to target specific systems. Restricting disclosure of this information helps maintain the confidentiality of the network architecture.

Good Practice

Techniques such as Network Address Translation (NAT), placing systems behind proxy servers, and using private IP address spaces help prevent the disclosure of internal addressing information. Only authorized individuals should have access to internal routing information.

1.4: The disclosure of internal IP addresses and routing information is limited to only authorized parties.
  • Examine configurations of NSCs to verify that the disclosure of internal IP addresses and routing information is limited to only authorized parties.
  • Interview personnel and examine documentation to verify that controls are implemented such that any disclosure of internal IP addresses and routing information is limited to only authorized parties.
Description

Requirement 1.4.1

Purpose

NSCs between trusted and untrusted networks are essential for controlling the flow of traffic and preventing unauthorized access. Without these controls, untrusted networks could directly access systems and data in trusted network segments.

Good Practice

NSCs should be placed at all connection points between trusted and untrusted networks. This includes connections to the Internet, partner networks, and other external networks. The NSCs should enforce policies that restrict traffic to only what is necessary.

Requirement 1.4.2

Purpose

Restricting inbound traffic from untrusted networks helps prevent unauthorized access and reduces the risk of attacks against systems in trusted network segments. Allowing only necessary traffic minimizes the attack surface.

Good Practice

Inbound traffic from untrusted networks should be limited to communications with system components that are authorized to provide publicly accessible services, protocols, and ports. All other inbound traffic should be denied.

Definitions

Untrusted networks include any network that is external to the networks belonging to the entity under review, or that is out of the entity's ability to control or manage.

Requirement 1.4.3

Purpose

Anti-spoofing measures help prevent attackers from using forged source IP addresses to bypass network security controls. Without these measures, traffic from untrusted networks could appear to originate from trusted internal networks.

Good Practice

NSCs should be configured to detect and block traffic with spoofed source addresses. This includes implementing ingress filtering to verify that source addresses are valid and egress filtering to prevent internal addresses from leaving the network.

Requirement 1.4.4

Purpose

System components that store cardholder data should not be directly accessible from untrusted networks. Placing these components in an internal network zone behind a DMZ or other security controls helps protect them from direct attack.

Good Practice

Systems that store cardholder data should be placed in internal network zones that are not directly accessible from the Internet or other untrusted networks. Access to these systems should be mediated through proxy servers, application firewalls, or other security controls.

Requirement 1.4.5

Purpose

Disclosing internal IP addresses and routing information to external parties can provide attackers with valuable information about the internal network topology, making it easier to target specific systems. Restricting disclosure of this information helps maintain the confidentiality of the network architecture.

Good Practice

Techniques such as Network Address Translation (NAT), placing systems behind proxy servers, and using private IP address spaces help prevent the disclosure of internal addressing information. Only authorized individuals should have access to internal routing information.

1.5: Security controls are implemented on any computing devices, including company- and employee-owned devices, that connect to both untrusted networks (including the Internet) and the CDE as follows: (a) Specific configuration settings are defined to prevent threats being introduced into the entity’s network, (b) Security controls are actively running, (c) Security controls are not alterable by users of the computing devices unless specifically documented and authorized by management on a case-by-case basis for a limited period.
  • Examine policies and configuration standards and interview personnel to verify security controls for computing devices that connect to both untrusted networks, and the CDE, are implemented in accordance with all elements specified in this requirement.
  • Examine configuration settings on computing devices that connect to both untrusted networks and the CDE to verify settings are implemented in accordance with all elements specified in this requirement.
Description

Requirement 1.5.1

Purpose

Computing devices that connect to both untrusted networks and the CDE can serve as entry points for attackers to access the CDE. If such devices are compromised while connected to an untrusted network, the compromise could extend into the CDE. Security controls on these devices help mitigate this risk.

Good Practice

Personal firewall or equivalent functionality should be active on all portable computing devices and devices owned by employees that connect to both the Internet and the CDE. The security controls should be configured according to specific organizational standards and should not be alterable by users without authorization.

Definitions

A personal firewall is a software-based security control that monitors and controls network traffic to and from a computing device. Equivalent functionality may be provided by endpoint security software or other security tools.