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Latest Network and Certificate System Security Requirements

Introduction

Overview

Scope and Applicability:

In these Requirements, the CA is responsible for all tasks performed by Delegated Third Parties and Trusted Roles, and the CA SHALL define, document, and disclose to its auditors:

  1. the tasks assigned to Delegated Third Parties or Trusted Roles;
  2. the arrangements made with Delegated Third Parties to ensure compliance with these Requirements; and
  3. the relevant practices, procedures, and/or systems implemented by Delegated Third Parties.

Guiding Principle and Goal:

CAs are expected to maintain a very high level of security for their infrastructure and systems because the certificates they issue play a vital role in the security of the internet, email, and software distribution.

Desired Outcomes:

The following are outcomes that this document seeks to achieve:

  • CAs are able to clearly understand the minimum security requirements found in this document and successfully adapt/implement these Requirements to their own infrastructure and architecture.
  • Audit and assessment bodies are able to accurately map these Requirements to the specific implementations observed during audit engagements, and judge compliance against these Requirements.
  • CA organizations, operations, infrastructure, and CA Private Keys and certificates are not compromised.
  • Controls are implemented that protect against external and internal threats, including mistakes.
  • Through a combination of credentialing, role management, and training, CA personnel are limited in their ability to negatively impact the CA’s operations, whether intentionally or unintentionally.
  • Systems provide sufficient artifacts to enable traceability of all events and identification and investigation of anomalous events.
  • Continuous monitoring and testing are conducted to identify any vulnerabilities or weaknesses that need to be addressed promptly and to ensure the effectiveness of implemented security controls.
  • CA Infrastructure is maintained, including timely patching of software and firmware, and hardware is kept sufficiently up to date to support software and systems running on it.
  • A framework is provided for assessment of infrastructure and systems not directly owned or controlled by the CA.
  • The use of infrastructure or systems not owned or controlled by the CA is possible, if such use aligns with these Requirements and all other applicable standards, policies, or requirements.

Document History

Ver.BallotDescriptionAdoptedEffective*
1.083Original Version Adopted3‐Aug‐1201‐Jan‐13
1.1210Misc. Changes to NCSSRs31‐Aug‐1709-Mar-18
1.2SC3Two-Factor Authentication and Password Improvements16‐Aug‐1815-Sep-18
1.3SC21The Network and Certificate Systems Security Requirements Section 3 (Log Integrity Controls)26‐Sep‐194-Nov-2019
1.4SC29System Configuration Management7-May-208-Jun-2020
1.5SC28Logging and Log Retention10-Sep-202019-Sep-2020
1.6SC39Definition of Critical Vulnerability16-Feb-202130-Mar-2021
1.7SC41Reformatting the BRs, EVGs, and NCSSRs24-Feb-20215-Apr-2021
2.0NS-003Restructure NCSSRs06-May-202405-Jun-2024

* Effective Date based on completion of 30‐day IPR review without filing of any Exclusion Notices.

Definitions

Air-Gapped: Physically and logically separated, disconnected, and isolated from all other Systems.

CA Infrastructure: Collectively the infrastructure used by the CA or Delegated Third Party which qualifies as a:

  • Certificate Management System;
  • Certificate System;
  • Delegated Third Party System;
  • Issuing System;
  • Root CA System (Air-Gapped and otherwise); or
  • Security Support System.

Certificate Management System: A system used by a CA or Delegated Third Party to process, approve issuance of, or store certificates or certificate status information, including the database, database server, and storage.

Certificate System: A system used by a CA or Delegated Third Party to access, process, or manage data or provide services related to:

  1. identity validation;
  2. identity authentication;
  3. account registration;
  4. certificate application;
  5. certificate approval;
  6. certificate issuance;
  7. certificate revocation;
  8. authoritative certificate status; or
  9. key escrow.

Common Vulnerability Scoring System (CVSS): A quantitative model used to measure the base level severity of a vulnerability (see http://nvd.nist.gov/vuln-metrics/cvss).

Critical Security Event: An event, set of circumstances, or anomalous activity that could lead to a circumvention of CA Infrastructure security controls or compromise of CA Infrastructure integrity or operational continuity, including, but not limited to, excessive login attempts, attempts to access prohibited resources, DoS/DDoS attacks, attacker reconnaissance, excessive traffic at unusual hours, signs of unauthorized access, system intrusion, or physical compromise of component integrity.

Critical Vulnerability: A system vulnerability that has a CVSS v2.0 score of 7.0 or higher according to the NVD or an equivalent to such CVSS rating (see https://nvd.nist.gov/vuln-metrics/cvss), or as otherwise designated as a Critical Vulnerability by the CA or the CA/Browser Forum.

Delegated Third Party: A natural person or legal entity that is not the CA and that operates any part of a Certificate System.

Delegated Third Party System: Any part of a Certificate System used by a Delegated Third Party while performing the functions delegated to it by the CA.

Issuing System: A system used to sign certificates or validity status information.

Key Pair: The Private Key and its associated Public Key.

Multi-Factor Authentication: An authentication mechanism consisting of two or more of the following independent categories of credentials (i.e. factors) to verify the user’s identity for a login or other transaction:

  1. something the user knows (knowledge factor);
  2. something the user has (possession factor); and
  3. something the user is (inherence factor). Each factor is independent of the other(s).

Multi-Party Control: An access control mechanism which requires two or more separate, authorized users to successfully authenticate with their own unique credentials prior to access being granted.

National Vulnerability Database (NVD): A database that includes the Common Vulnerability Scoring System (CVSS) scores of security-related software flaws, misconfigurations, and vulnerabilities associated with systems (see http://nvd.nist.gov/).

Network Equipment: Hardware devices and components that facilitate communication and data transfer within the CA Infrastructure.

OWASP Top Ten: A list of application vulnerabilities published by the Open Web Application Security Project (see https://www.owasp.org/index.php/Category:OWASP_Top_Ten_Project).

Penetration Test: A process that identifies and attempts to exploit openings and vulnerabilities on systems through the active use of known attack techniques, including the combination of different types of exploits, with a goal of breaking through layers of defenses and reporting on unpatched vulnerabilities and system weaknesses.

Physically Secure Environment: A controlled and protected physical space consisting minimally of a physical environment which is:

  1. protected by security controls which address the topics outlined in section 4.5.1 of RFC 3647; and
  2. designed, built, and maintained in accordance with Risk Assessments conducted by the CA.

Principle of Least Privilege: The principle that users, devices, and software should only have the minimum necessary access and privileges to complete their functions.

Private Key: The cryptographic key of an asymmetric Key Pair that is kept secret by the holder of the Key Pair. It may be used to create digital signatures and/or to decrypt data that were encrypted by the corresponding Public Key.

Public Key: The cryptographic key of an asymmetric Key Pair that can be made public without compromising the security of the Key Pair. It may be used to verify digital signatures and/or to encrypt data that can be decrypted by the corresponding Private Key.

Requirements: The Network and Certificate System Security Requirements found in this document.

Risk Assessment: A formal process that:

  1. Identifies and documents foreseeable internal and external threats to the CA Infrastucture that could result in:
    • unauthorized access to the CA Infrastructure;
    • disclosure of data stored in the CA Infrastructure;
    • misuse of the CA Infrastructure; or
    • unapproved alteration or destruction of any part of the CA Infrastructure;
  2. Assesses and documents the likelihood and potential damage of each identified threat, taking into consideration minimally the sensitivity and criticality of the CA Infrastructure; and
  3. Assesses and documents the sufficiency of the policies, procedures, controls, information systems, technology, and other arrangements that the CA has in place to counter each identified threat.

Root CA Certificate: A self-signed and self-issued certificate where:

  1. the issuer and subject of the certificate are the same; and
  2. the digital signature of the certificate is:
    • generated using the Private Key of a Key Pair whose corresponding Public Key is bound to the certificate; and
    • verified using the Public Key contained in the certificate.

Root CA Private Key: The Private Key associated with a Root CA Certificate.

Root CA System: A system used to:

  1. generate a Key Pair whose Private Key is or will be a Root CA Private Key;
  2. store a Root CA Private Key; or
  3. create digital signatures using a Root CA Private Key.

SANS Top 25: A list created with input from the SysAdmin, Audit, Network, and Security (SANS) Institute and the Common Weakness Enumeration (CWE) that identifies the Top 25 Most Dangerous Software Errors that lead to exploitable vulnerabilities (see http://www.sans.org/top25-software-errors/).

Security Support System: A system or set of systems supporting the security of the CA Infrastructure, which minimally includes:

  1. authentication;
  2. network boundary control;
  3. audit logging;
  4. audit log reduction and analysis;
  5. vulnerability scanning;
  6. physical intrusion detection;
  7. host-based intrusion detection; and
  8. network-based intrusion detection.

System: One or more pieces of equipment or software that stores, transforms, or communicates data.

Trusted Role: An employee or contractor of a CA or Delegated Third Party who has authorized access to any component of CA Infrastructure.

Vulnerability Scan: A process that uses manual or automated tools to probe internal and external systems to check and report on the status of operating systems, services, and devices exposed to the network and the presence of vulnerabilities listed in the NVD, OWASP Top Ten, or SANS Top 25.

Workstation: A device, such as a phone, tablet, or desktop or laptop computer, which is:

  1. connected to the same network as CA Infrastructure and/or Network Equipment; and
  2. capable of accessing CA Infrastructure and/or Network Equipment.

Requirements

Prior to 2024-11-12, the CA SHALL adhere to these Requirements or Version 1.7 of the Network and Certificate System Security Requirements. Effective 2024-11-12, the CA SHALL adhere to these Requirements.

1. CA Infrastructure and Network Equipment Configuration

1.1 Network Segmentation

1.1.1

CA Infrastructure MUST be segmented into separate networks based on the functional and/or logical relationships of CA Infrastructure components.

1.1.1.1

Network segmentation MUST be designed and implemented using Network Equipment, such as:

  • firewalls
  • network switches
  • physically separate networks

Network segmentation MAY leverage software, such as:

  • virtual LANs (VLANs) and VLAN access control lists
  • software-defined networking
  • virtual private networks (VPNs)
1.1.1.2

Network segmentation SHOULD be designed and implemented in a manner that:

  1. minimizes attack surfaces;
  2. limits lateral movement within networks;
  3. restricts traffic flow between different network segments; and
  4. protects all CA Infrastructure components from unauthorized access.

1.2 CA Infrastructure Security

1.2.1

CA Infrastructure MUST be in a Physically Secure Environment.

1.2.2

CA Infrastructure and Network Equipment MUST be implemented and configured to authenticate and encrypt connections:

  1. between CA Infrastructure components; and
  2. between CA Infrastructure and non-CA Infrastructure.

CA Infrastructure and Network Equipment MUST be implemented and configured in a manner that minimizes unnecessary active components and capabilities such that:

  1. all connections, communications, applications, services, protocols, and ports not used are removed and/or disabled; and
  2. only connections, communications, applications, services, protocols, and ports necessary and approved under the Principle of Least Privilege are enabled.
1.2.3

Equivalent security MUST be implemented on all Systems on the same network as any CA Infrastructure component.

1.3 Change Management

The CA MUST establish and maintain a change management process which is minimally:

  1. documented comprehensively;
  2. authoritative for:
    1. all personnel in Trusted Roles;
    2. management of Network Equipment; and
    3. management of CA Infrastructure;
  3. reviewed annually;
  4. updated as needed; and
  5. approved:
    • with each update;
    • prior to going into effect; and
    • by personnel in applicable Trusted Roles.

The CA MUST ensure the change management process:

  1. enables identification, documentation, and remediation of risks associated with introducing, modifying, or removing:
    • Trusted Role definitions;
    • Trusted Role appointments;
    • Network Equipment; or
    • CA Infrastructure;
  2. addresses managing exceptions and responding to emergencies; and
  3. incorporates procedures for change reversal where applicable.

The CA MUST ensure that all changes are completed in accordance with such a change management process for:

  1. Trusted Role definitions;
  2. Trusted Role appointments;
  3. Network Equipment; and
  4. CA Infrastructure.

2. Access Control

Within this Section 2, references to “access” include all physical and logical access, unless otherwise specified.

2.1 Trusted roles

The CA MUST define Trusted Roles for the personnel who design, build, develop, implement, operate, and maintain its CA Infrastructure and Network Equipment.

Each Trusted Role MUST have its responsibilities, privileges, and access documented.

Each Trusted Role MUST be assigned responsibilities, privileges, and access in a manner consistent with:

  1. the Principle of Least Privilege; and
  2. requirements of Multi-Party Control.
2.1.1

The CA MUST ensure personnel assigned to a Trusted Role act only within the scope of their Trusted Role(s) when performing responsibilities, using privileges, or using access assigned to that Trusted Role.

2.2 Access Management

2.2.1

The CA MUST ensure access to CA Infrastructure and/or Network Equipment is:

  1. limited to personnel assigned to applicable Trusted Roles; and
  2. based on the Principle of Least Privilege.
2.2.1.1

The CA MUST ensure personnel assigned to Trusted Roles that are authorized to access or authenticate to CA Infrastructure and/or Network Equipment use unique authentication credentials created by or assigned to the authorized individual.

2.2.1.2

The CA MUST NOT allow group accounts or shared role credentials to authenticate to or access CA Infrastructure and/or Network Equipment.

2.2.1.3

The CA MUST ensure authentication credentials are changed or revoked when associated authorizations are changed or revoked.

The CA MUST ensure access to CA Infrastructure and Network Equipment is disabled for personnel within twenty-four (24) hours of the termination of an individual’s employment or contracting relationship.

2.2.1.4

The CA MUST ensure any account capable of authenticating to or accessing CA Infrastructure or Network Equipment is reviewed at a minimum frequency of every three (3) months.

The CA MUST ensure any account that is not necessary for the operation of CA Infrastructure or Network Equipment is deactivated or removed such that the account is no longer capable of authenticating to or accessing CA Infrastructure or Network Equipment.

2.2.1.5

The CA MUST ensure security measures are implemented that minimize the susceptibility of CA Infrastructure to unauthorized access through repeated attempts to authenticate to or access an account that has access to CA Infrastructure. These measures SHOULD prevent brute-force attacks which systematically enumerate authentication credentials such as username and password combinations. These measures SHOULD be based on a Risk Assessment.

2.2.2

The CA SHOULD ensure Workstations are configured in a manner that prevents continued access to the Workstation after a set period of inactivity, for example by automatically logging off active users. The allowed and configured duration of inactivity MUST be selected based on the CA’s assessment of associated risks.

The CA MAY allow a Workstation to remain active and unattended if the Workstation is otherwise secured and running administrative tasks that would be interrupted by an inactivity time‐out or system lock.

The CA MUST ensure personnel assigned to Trusted Roles log out of or lock their Workstation(s) when not in active use.

2.2.3

The CA MUST enforce the use of Multi-Factor Authentication for:

  1. accounts on CA Infrastructure; and
  2. access to CA Infrastructure.

Authentication based on the possession of a certificate can be used as part of Multi-factor Authentication only if the associated Private Key is stored in a key storage device certified as:

  • meeting at least FIPS 140-2 or 140-3, level 2 overall or level 3 physical; or
  • validated against a Common Criteria Protection Profile for Digital Signatures at EAL 4 augmented with AVA_VAN >=5 and ALC_FLR >= 2.
2.2.4

The CA MUST enforce the use of Multi-Party Control for physical access to any Root CA System.

2.2.5

The CA SHOULD ensure passwords used as authentication credentials for accounts on CA Infrastructure, Network Equipment, or Workstations are generated and managed in accordance with NIST 800-63B Appendix A.

The CA SHALL NOT require periodic password changes with a period less than two (2) years.

The CA MUST ensure passwords used as authentication credentials for accounts on CA Infrastructure have a minimum of twelve (12) characters.

The CA MUST ensure passwords used as authentication credentials for accounts on Network Equipment or Workstations have a minimum of eight (8) characters.

2.2.6

The CA MUST ensure any remote connection that enables administration of and/or access to CA Infrastructure:

  1. originates from a Workstation owned and/or controlled by the CA;
  2. is made through a temporary, non‐persistent, and encrypted channel;
  3. is authenticated using Multi‐Factor Authentication; and
  4. is made to a Network Equipment asset which:
    • is located within the CA’s network;
    • is secured in accordance with these Requirements; and
    • mediates the remote connection to the CA Infrastructure.

3. Monitoring, Logging, Auditing, and Incident Response

3.1 Monitoring and Logging

3.1.1

The CA MUST identify and document the monitoring and logging capabilities of CA Infrastructure and Network Equipment.

The CA SHOULD establish, evaluate, and maintain policies and procedures for:

  1. identifying and utilizing the monitoring and logging capabilities of CA Infrastructure and Network Equipment; and
  2. retaining, parsing, securing, and archiving the audit logs output by CA Infrastructure and Network Equipment.

The CA SHOULD review and update such policies and procedures at least annually.

3.1.1.1

The CA MUST ensure the monitoring and logging capabilities of CA Infrastructure and Network Equipment are enabled to the extent necessary to meet:

  1. these Requirements; and
  2. applicable obligations that depend on such audit logs (such as the requirements in Section 5.4.1 (3) of the Baseline Requirements for the Issuance and Management of Publicly-Trusted TLS Server Certificates).
3.1.1.2

The CA MUST ensure audit logs produced by the monitoring and logging capabilities of CA Infrastructure and Network Equipment include activities and/or events:

  1. necessary to detect possible:
    1. Critical Security Events; and
    2. modifications to CA Infrastructure not authorized through the change management process outlined in Section 1.3; and
  2. with sufficient detail to meet
    1. these Requirements; and
    2. applicable obligations that depend on such audit logs (such as the requirements in Section 5.4.1 (3) of the Baseline Requirements for the Issuance and Management of Publicly-Trusted TLS Server Certificates).
3.1.2

The CA MUST ensure the integrity of logging processes within CA Infrastructure is monitored through:

  1. continuous automated monitoring operating within CA Infrastructure; or
  2. a review by personnel assigned to applicable Trusted Roles at least once every 31 days.

The CA MUST ensure such integrity monitoring is configured and managed in a manner sufficiently effective to identify possible audit log compromise.

3.1.2.1

The CA MUST ensure audit logs are retained and/or archived for the amount of time necessary to meet:

  1. these Requirements; and
  2. applicable obligations which depend on such audit logs (such as the requirements in Section 5.4.1 (3) of the Baseline Requirements for the Issuance and Management of Publicly-Trusted TLS Server Certificates).

The CA SHOULD ensure retained and/or archived audit logs are kept and managed in a manner sufficiently effective to prevent unapproved alteration or access.

3.2 Audit Log Processing and Alerting

3.2.1

The CA MUST ensure audit logs are processed:

  1. through automated mechanisms under the control of personnel assigned to applicable Trusted Roles; and
  2. in a manner sufficiently effective to minimally identify possible:
    1. Critical Security Events; and
    2. unauthorized changes to CA Infrastructure.
3.2.2

The CA MUST ensure personnel assigned to applicable Trusted Roles are alerted via multiple mechanisms and/or communication channels of identified possible:

  1. audit log compromise;
  2. Critical Security Events; and
  3. unauthorized changes to CA Infrastructure.
3.2.3

The CA MUST ensure personnel assigned to applicable Trusted Roles commence an initial response to alerts of Section 3.2.2 within twenty-four (24) hours of the alert being generated.

3.2.3.1

The CA MUST ensure the initial response confirms whether the alert identifies a legitimate

  1. audit log compromise;
  2. Critical Security Event; and/or
  3. unauthorized change to the CA Infrastructure.

The CA MUST ensure personnel assigned to applicable Trusted Roles create and follow an incident response plan for all legitimate alerts.

3.2.3.2

The CA SHOULD ensure incident response plans minimally include:

  1. identification of the potential impact, scope, and severity of the incident;
  2. containment of the incident to minimize further impact; and
  3. identification and mitigation or eradication of the incident root cause(s).

4. Vulnerability Detection and Patch Management

Certification Authorities and Delegated Third Parties SHALL:

  1. Implement intrusion detection and prevention controls under the control of CA or Delegated Third Party Trusted Roles to protect Certificate Systems against common network and system threats;

  2. Document and follow a vulnerability correction process that addresses the identification, review, response, and remediation of vulnerabilities;

  3. Undergo or perform a Vulnerability Scan

    1. within one (1) week of receiving a request from the CA/Browser Forum,
    2. after any system or network changes that the CA determines are significant, and
    3. at least every three (3) months, on public and private IP addresses identified by the CA or Delegated Third Party as the CA’s or Delegated Third Party’s Certificate Systems;
  4. Undergo a Penetration Test on the CA’s and each Delegated Third Party’s Certificate Systems on at least an annual basis and after infrastructure or application upgrades or modifications that the CA determines are significant;

  5. Record evidence that each Vulnerability Scan and Penetration Test was performed by a person or entity (or collective group thereof) with the skills, tools, proficiency, code of ethics, and independence necessary to provide a reliable Vulnerability Scan or Penetration Test; and

  6. Do one of the following within ninety-six (96) hours of discovery of a Critical Vulnerability not previously addressed by the CA’s vulnerability correction process:

    1. Remediate the Critical Vulnerability;

    2. If remediation of the Critical Vulnerability within ninety-six (96) hours is not possible, create and implement a plan to mitigate the Critical Vulnerability, giving priority to

      1. vulnerabilities with high CVSS scores, starting with the vulnerabilities the CA determines are the most critical (such as those with a CVSS score of 10.0) and
      2. systems that lack sufficient compensating controls that, if the vulnerability were left unmitigated, would allow external system control, code execution, privilege escalation, or system compromise; or
    3. Document the factual basis for the CA’s determination that the vulnerability does not require remediation because

      1. the CA disagrees with the NVD rating,
      2. the identification is a false positive,
      3. the exploit of the vulnerability is prevented by compensating controls or an absence of threats; or
      4. other similar reasons.
  7. Apply recommended security patches to Certificate Systems within six (6) months of the security patch’s availability, unless the CA documents that the security patch would introduce additional vulnerabilities or instabilities that outweigh the benefits of applying the security patch.

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