The following sections of this document provide operational security guidelines.
Operational security guidelines are required to operate a secure blockchain infrastructure and software. Only in this way, a certain level of security and trust can be guaranteed.
The following specifications should be implemented:
- Secure organizational structure
- Continuous global safe operation
- Regulate security for administrative operations
- Ongoing operation and integrity of your employees
- Physical security requirements
- Security requirements for outsourcing to a third-party provider
- Compliance directive for the operator
- Authentication and authorization of the stewards and nodes in the network
- Certified that the nodes running in a secure environment
- Separation of public and internal systems regulated
- Possibilities of remote maintenance
- Realization of access control
- Update intervals of nodes and internal systems
- Regulation of access control over the network
- Authorization of the nodes in the network
- Ensuring the ongoing integrity of the system and software
- Emergency concept
Drawback: Too high safety requirements could lead to less network members.
Unresolved questions: Uniform certified regulations for Blockchain operators.
References to best practices, examples
We can look at the Sovrin Steward Technical and Organizational Policies as an example implementation:
General Security Policies 1. A Steward MUST maintain and follow IT security policies and practices that are integral to maintain protection of all services provided in association with the Sovrin Steward Agreement (“Steward Services”). These policies MUST be mandatory for all employees of the Steward involved with providing the Steward Services. The Steward shall designate its CIO or another officer to provide executive oversight for such policies, including formal governance and revision management, employee education, and compliance enforcement.
A Steward MUST review its IT security policies at least annually and amend such policies as the Steward deems reasonable to maintain protection of its Steward Services.
Because Node administrators are a potential threat vector, a Steward MUST maintain and follow its standard mandatory employment verification requirements for all new hires involved with providing its Steward Services and will extend such requirements to wholly-owned subsidiaries involved with providing its Steward Services. In accordance with the Steward's internal process and procedures, these requirements MUST be periodically reviewed and include, but may not be limited to, criminal background checks, proof of identity validation, and additional checks as deemed necessary by the Steward. Each Steward company is responsible for implementing these requirements in its hiring process as applicable and permitted under local law.
Employees of a Steward involved with providing its Steward Services MUST complete security and privacy education annually and certify each year that they will comply with the Steward's ethical business conduct, confidentiality, security, privacy, and data protection policies. Additional policy and process training MUST be provided to persons granted administrative access to components that are specific to their role within the Steward's operation and support of its Steward Services.
If a Steward hosts its Node in its own data center, the Steward’s security policies MUST also adequately address physical security and entry control according to industry best practices.
If the Steward hosts its Node using a third-party Hosting Provider, the Steward MUST ensure that the security, privacy, and data protection policies of the Hosting Provider meet the requirements in this document.
A Steward MUST make available to the Sovrin Foundation upon request evidence of stated compliance with these policies and any relevant accreditations held by the Steward, including certificates, attestations, or reports resulting from accredited third-party audits, such as ISO 27001, SSAE SOC 2, or other industry standards.
Node Security Policies
MUST maintain Steward keys on a separate machine from the machine that runs their node. This machine, called the “CLI (Command Line Interface) system”, uses Steward keys to authorize the Node to participate in the pool, and is thus the basis for trust for the node and the Steward’s identity on the network. The CLI system is not required to have high-end hardware, but in terms of IT best practices for security, it must meet or exceed the standards for the Node (see following items).
MUST provide certification that their Node runs in a locked datacenter with appropriate levels of security, including the specifications that they target (e.g., SSAE 16 type II compliance; other standards may also be acceptable).
MUST assert that their Node is isolated from internal systems of a Steward (because the Validator Node is publicly visible and thus an inappropriate candidate for access to privileged internal networks).
MUST assert that their Node, and its underlying systems, uses state-of-the-art authentication for remote access (at least SSH with key plus password plus source IP firewall rule, and two-factor authentication wherever possible).
MUST NOT allow access (remote or local) to the Node or CLI systems by anyone other than assigned admins.
MUST apply the latest security patches within one (1) week or less (24 hours or less is recommended).
MUST attest that the Node runs on a server protected by a firewall that, at minimum:
Disallows public ingress except on ports used by the Node software (different machines may choose to expose ledger features on different ports, so no standard port setup is required).
Optionally enables SSH, Remote Desktop, and similar remote access tools but constrains ingress for these tools in some way that excludes the public but allows access for admins.
Locks down egress ports to limit the ability to jump from Node to some other location.
MUST run the Steward security check tool as requested, and MUST receive TGB approval of the results before the Node is authorized to participate in consensus.
MUST run the Steward security check tool from time to time as requested by the TGB and provide the test results report to the TGB within three (3) business days.
The emergency concept should handle risks that threat the functionality of the network or components. Therefore, it should cover critical aspects like integrity, authenticity, availability, confidentiality, pseudonymity, decentralization, robustness against abusal, transparency, resource requirements and throughput.
For general information on blockchain security take this or newer literature in consideration for security concepts: https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Krypto/Blockchain_Analyse.pdf?__blob=publicationFile&v=5
Bibliography of selected references
Authors: David Maas, Kevin Wittek, Chinmay Khandekar, Daniel Theis
Status: work in progress
Last modified: 2020-10-21