sec-design.md

BUSINESS POSTURE

This project, dnscontrol, aims to solve the problem of managing DNS records across multiple DNS providers in a consistent, automated, and auditable way. Organizations often use different DNS providers for various reasons (cost, features, redundancy). Managing DNS records manually across these providers is error-prone, time-consuming, and lacks version control and audit trails. dnscontrol addresses these challenges by providing a declarative configuration approach, allowing users to define their desired DNS state in code and automatically synchronize it with their DNS providers.

Business Priorities and Goals:

• Centralized DNS Management: Provide a single tool to manage DNS records across multiple providers, simplifying operations and reducing complexity.
• Automation: Automate DNS record updates, reducing manual errors and improving efficiency.
• Version Control and Auditability: Treat DNS configuration as code, enabling version control, collaboration, and audit trails.
• Consistency and Reliability: Ensure consistent DNS configuration across providers and improve DNS reliability through automated synchronization.
• Infrastructure as Code: Integrate DNS management into the Infrastructure as Code (IaC) paradigm.

Business Risks:

• Availability Risk: Misconfiguration or failures in dnscontrol could lead to DNS outages, impacting website and service availability.
• Data Integrity Risk: Incorrect DNS record updates could lead to misrouting of traffic and potential data breaches or service disruptions.
• Security Risk: Compromise of dnscontrol configuration or access could allow attackers to manipulate DNS records, leading to phishing, man-in-the-middle attacks, or denial of service.
• Provider Dependency Risk: Reliance on dnscontrol and its supported providers introduces dependency risks. Changes in providers' APIs or dnscontrol's compatibility could disrupt DNS management.
• Configuration Drift Risk: If manual changes are made outside of dnscontrol, configuration drift can occur, leading to inconsistencies and potential issues.

SECURITY POSTURE

Existing Security Controls:

• security control: Code Review - The project is open source and hosted on GitHub, allowing for community code review. Implemented in: GitHub repository, Pull Request process.
• security control: Version Control - DNS configurations are stored in version control (Git), providing an audit trail of changes. Implemented in: Git repository.
• security control: Provider API Security - dnscontrol relies on the security mechanisms provided by the DNS providers' APIs (e.g., API keys, OAuth). Implemented in: Provider SDKs and API integrations within dnscontrol.
• security control: Least Privilege (Configuration) - Users should ideally grant dnscontrol API credentials with the least privileges necessary for DNS management. Implemented in: User responsibility when configuring provider credentials.

Accepted Risks:

• accepted risk: Open Source Vulnerabilities - As an open-source project, dnscontrol may be susceptible to vulnerabilities. The project relies on community contributions and maintainer efforts for vulnerability detection and patching.
• accepted risk: Dependency Vulnerabilities - dnscontrol depends on third-party libraries and provider SDKs, which may contain vulnerabilities.
• accepted risk: Configuration Errors - Users are responsible for writing correct and secure DNS configurations. Misconfigurations can lead to security issues.
• accepted risk: Credential Management - Users are responsible for securely managing and storing API credentials for DNS providers.

Recommended Security Controls:

• security control: Automated Security Scanning - Implement automated security scanning (SAST, DAST, dependency scanning) in the CI/CD pipeline to detect vulnerabilities in the code and dependencies.
• security control: Secret Management - Integrate with a secret management solution (e.g., HashiCorp Vault, AWS Secrets Manager) to securely store and manage DNS provider API credentials instead of storing them directly in configuration files or environment variables.
• security control: Input Validation and Sanitization - Implement robust input validation and sanitization for all user inputs, especially in configuration parsing and provider API interactions, to prevent injection attacks.
• security control: Role-Based Access Control (RBAC) - If dnscontrol is used in a team environment, consider implementing or recommending RBAC mechanisms to control who can manage DNS configurations and which providers they can access.
• security control: Audit Logging - Enhance audit logging to record all actions performed by dnscontrol, including configuration changes, provider API calls, and errors, for security monitoring and incident response.

Security Requirements:

• Authentication:
  • Requirement: dnscontrol itself does not require user authentication as it is a CLI tool. Authentication is handled by the underlying operating system and access controls to the system where dnscontrol is executed.
  • Requirement: Authentication to DNS providers is required via API keys, tokens, or other provider-specific authentication mechanisms. dnscontrol must securely handle these credentials during runtime.
• Authorization:
  • Requirement: Authorization is managed at the DNS provider level. dnscontrol operates with the permissions granted to the API credentials it uses.
  • Requirement: Users should follow the principle of least privilege when configuring API credentials for dnscontrol, granting only necessary permissions for DNS management.
• Input Validation:
  • Requirement: dnscontrol must validate all inputs, including configuration files, command-line arguments, and responses from DNS provider APIs, to prevent injection attacks and ensure data integrity.
  • Requirement: Configuration files should be validated against a schema to ensure correctness and prevent unexpected behavior.
• Cryptography:
  • Requirement: dnscontrol should use cryptography to protect sensitive data in transit and at rest, such as API credentials if they are stored locally (though secret management is recommended).
  • Requirement: Communication with DNS providers over APIs should be encrypted using HTTPS.
  • Requirement: Consider using encryption for storing configuration files at rest if they contain sensitive information.

DESIGN

C4 CONTEXT

flowchart LR
    subgraph "DNS Infrastructure"
        direction TB
        DNS_Providers[/"DNS Providers"\n(e.g., Cloudflare, Route53, Google Cloud DNS)/]
    end
    User[/"User"\n(DevOps Engineer,\nSystem Administrator)/] --> dnscontrol
    dnscontrol[/"dnscontrol"\n(DNS Management CLI Tool)/] --> DNS_Providers
    DNS_Providers --> Internet[/"Internet"\n(Public Network)/]
    Internet --> Users_Internet[/"Internet Users"/]

    linkStyle 0,1,2,3 stroke-width:2px;

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Context Diagram Elements:

• Element:

  • Name: User
  • Type: Person
  • Description: DevOps engineers or system administrators who use dnscontrol to manage DNS records.
  • Responsibilities: Define desired DNS configuration in dnscontrol configuration files, execute dnscontrol commands to apply changes, manage API credentials for DNS providers.
  • Security controls: Operating system level access controls to the system where dnscontrol is executed, secure storage of DNS provider credentials (ideally using secret management).

• Element:

  • Name: dnscontrol
  • Type: Software System
  • Description: A command-line tool that automates DNS record management across multiple DNS providers based on declarative configuration files.
  • Responsibilities: Read DNS configuration files, interact with DNS provider APIs to retrieve and update DNS records, manage state and track changes, provide command-line interface for user interaction.
  • Security controls: Input validation of configuration files and command-line arguments, secure handling of DNS provider credentials during runtime, logging of actions, potential integration with secret management solutions.

• Element:

  • Name: DNS Providers
  • Type: External System
  • Description: Third-party DNS service providers (e.g., Cloudflare, AWS Route53, Google Cloud DNS) that host and manage DNS records.
  • Responsibilities: Host and serve DNS records, provide APIs for managing DNS records, authenticate and authorize API requests.
  • Security controls: Provider-specific security controls for API access (API keys, OAuth), DNSSEC, DDoS protection, access control lists.

• Element:

  • Name: Internet
  • Type: External System
  • Description: The public internet network through which DNS queries are resolved.
  • Responsibilities: Route network traffic, provide connectivity between users and DNS infrastructure.
  • Security controls: DDoS protection at network level, routing security protocols (BGP security).

• Element:

  • Name: Internet Users
  • Type: Person
  • Description: End-users who access websites and services that rely on the DNS records managed by dnscontrol.
  • Responsibilities: Initiate DNS queries to resolve domain names to IP addresses.
  • Security controls: Rely on DNSSEC and secure DNS resolvers for secure DNS resolution.

C4 CONTAINER

flowchart LR
    subgraph "dnscontrol Container"
        direction TB
        CLI[/"CLI Application"\n(Go Binary)/]
        Config_Files[/"Configuration Files"\n(JavaScript/JSON)/]
        Provider_SDKs[/"Provider SDKs"\n(Go Libraries)/]
        State_Management[/"State Management"\n(Local Files,\nIn-Memory)/]
        Logging[/"Logging"/]
    end
    User[/"User"/] --> CLI
    CLI --> Config_Files
    CLI --> Provider_SDKs
    CLI --> State_Management
    CLI --> Logging
    Provider_SDKs --> DNS_Providers[/"DNS Providers"/]
    Logging --> Log_Storage[/"Log Storage"\n(File System,\nSyslog,\nCentralized Logging)/]

    linkStyle 0,1,2,3,4,5 stroke-width:2px;

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Container Diagram Elements:

• Element:

  • Name: CLI Application
  • Type: Application
  • Description: The dnscontrol command-line interface application, written in Go. It's the main executable that users interact with.
  • Responsibilities: Parse command-line arguments, read and parse configuration files, orchestrate interactions with Provider SDKs, manage state, handle errors, output logs and reports.
  • Security controls: Input validation of command-line arguments, secure handling of credentials in memory during runtime, logging of actions, integration with secret management for credential retrieval.

• Element:

  • Name: Configuration Files
  • Type: Data Store
  • Description: JavaScript or JSON files that define the desired DNS configuration in a declarative format.
  • Responsibilities: Store the desired DNS state, including domains, records, and provider-specific settings.
  • Security controls: Access control to configuration files (file system permissions), potential encryption at rest if containing sensitive information, version control of configuration files.

• Element:

  • Name: Provider SDKs
  • Type: Library
  • Description: Go libraries that provide abstractions and interfaces for interacting with specific DNS provider APIs.
  • Responsibilities: Implement provider-specific API interactions, handle authentication and authorization with DNS providers, translate dnscontrol's internal representation of DNS records to provider-specific API calls.
  • Security controls: Rely on the security of the SDKs themselves (dependency scanning), secure communication with provider APIs (HTTPS), handling of API credentials provided by the CLI application.

• Element:

  • Name: State Management
  • Type: Data Store
  • Description: Mechanisms for tracking the current state of DNS records and changes made by dnscontrol. Can be in-memory or persisted to local files.
  • Responsibilities: Store the last applied DNS configuration, track changes and diffs between desired and current state, optimize API calls to providers by avoiding unnecessary updates.
  • Security controls: Access control to state files if persisted to disk, secure handling of potentially sensitive data in state (though ideally state should not contain secrets).

• Element:

  • Name: Logging
  • Type: Component
  • Description: Component responsible for generating logs of dnscontrol's operations, including actions, errors, and debug information.
  • Responsibilities: Record events, errors, and debug information, format logs for readability and analysis, potentially send logs to different outputs (console, files, syslog, centralized logging).
  • Security controls: Secure storage of log files, access control to log files, potential redaction of sensitive information from logs, integration with centralized logging and monitoring systems for security analysis.

• Element:

  • Name: Log Storage
  • Type: Data Store
  • Description: Location where logs are stored. Can be file system, syslog, or centralized logging system.
  • Responsibilities: Persistently store logs for auditing, debugging, and security monitoring.
  • Security controls: Access control to log storage, secure configuration of log storage (e.g., encryption at rest for sensitive logs), log retention policies.

DEPLOYMENT

Deployment Architecture Option: Local Execution on Administrator's Workstation

flowchart LR
    subgraph "Administrator Workstation"
        direction TB
        dnscontrol_CLI[/"dnscontrol CLI"\n(Go Binary)/]
        Config_Files_Local[/"Configuration Files"\n(Local File System)/]
        Credentials_Local[/"Credentials"\n(Environment Variables,\nLocal Files)/]
    end
    Administrator[/"Administrator"\n(DevOps Engineer)/] --> Administrator_Workstation
    Administrator_Workstation --> DNS_Providers[/"DNS Providers"\n(Cloudflare, Route53, etc.)/]
    Administrator_Workstation --> Log_Files_Local[/"Log Files"\n(Local File System)/]

    linkStyle 0,1,2 stroke-width:2px;

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Deployment Diagram Elements (Local Execution):

• Element:

  • Name: Administrator Workstation
  • Type: Infrastructure
  • Description: The local computer of a DevOps engineer or system administrator where dnscontrol is executed.
  • Responsibilities: Provide execution environment for dnscontrol, store configuration files and potentially credentials, provide network connectivity to DNS providers.
  • Security controls: Operating system security controls, user authentication and authorization, endpoint security software, physical security of the workstation.

• Element:

  • Name: dnscontrol CLI
  • Type: Software
  • Description: The dnscontrol command-line executable running on the administrator's workstation.
  • Responsibilities: Execute dnscontrol commands, interact with configuration files and credentials, communicate with DNS providers.
  • Security controls: Same as Container: CLI Application security controls.

• Element:

  • Name: Configuration Files (Local)
  • Type: Data
  • Description: DNS configuration files stored on the administrator's local file system.
  • Responsibilities: Store DNS configuration.
  • Security controls: File system access controls, potential encryption at rest.

• Element:

  • Name: Credentials (Local)
  • Type: Data
  • Description: DNS provider API credentials stored as environment variables or in local files on the administrator's workstation.
  • Responsibilities: Provide authentication information for dnscontrol to access DNS provider APIs.
  • Security controls: File system access controls, ideally replaced with secret management or more secure credential storage mechanisms.

• Element:

  • Name: Log Files (Local)
  • Type: Data
  • Description: Log files generated by dnscontrol and stored on the administrator's local file system.
  • Responsibilities: Store logs for auditing and debugging.
  • Security controls: File system access controls.

• Element:

  • Name: DNS Providers
  • Type: External Service
  • Description: Remote DNS service providers.
  • Responsibilities: Host and manage DNS records.
  • Security controls: Provider-specific security controls.

BUILD

flowchart LR
    subgraph "Developer Environment"
        direction TB
        Developer[/"Developer"/] --> Code_Changes[/"Code Changes"\n(Git)/]
    end
    Code_Changes --> GitHub[/"GitHub Repository"\n(Source Code,\nWorkflows)/]
    subgraph "GitHub Actions CI"
        direction TB
        Build_Workflow[/"Build Workflow"\n(GitHub Actions)/]
        SAST_Scanner[/"SAST Scanner"\n(e.g., GoSec)/]
        Dependency_Scanner[/"Dependency Scanner"\n(e.g., Go Modules)/]
        Linter[/"Linter"\n(e.g., GolangCI-Lint)/]
        Test_Suite[/"Test Suite"/]
        Artifact_Storage[/"Artifact Storage"\n(GitHub Actions Artifacts)/]
    end
    GitHub --> Build_Workflow
    Build_Workflow --> SAST_Scanner
    Build_Workflow --> Dependency_Scanner
    Build_Workflow --> Linter
    Build_Workflow --> Test_Suite
    Build_Workflow --> Artifact_Storage
    Artifact_Storage --> Release_Process[/"Release Process"\n(GitHub Releases,\nDistribution)/]

    linkStyle 0,1,2,3,4,5,6,7,8 stroke-width:2px;

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Build Process Description:

1. Developer makes code changes and commits them to a Git repository hosted on GitHub.
2. GitHub triggers a Build Workflow defined in GitHub Actions upon code changes (e.g., push, pull request).
3. The Build Workflow performs the following steps:
   • Checkout code from the repository.
   • Run SAST Scanner (e.g., GoSec) to identify potential security vulnerabilities in the code.
   • Run Dependency Scanner (e.g., Go Modules vulnerability scanning) to check for vulnerabilities in dependencies.
   • Run Linter (e.g., GolangCI-Lint) to enforce code quality and style guidelines.
   • Execute Test Suite (unit tests, integration tests) to ensure code functionality and stability.
   • Build the dnscontrol CLI binary.
   • Store build artifacts (e.g., CLI binary, checksums) in GitHub Actions Artifact Storage.
4. Release Process:
   • Manually or automatically trigger a release process.
   • Create GitHub Releases, attaching build artifacts.
   • Potentially distribute binaries through other channels (e.g., package managers, website).

Build Process Security Controls:

• security control: Secure Code Repository - Using GitHub as a source code repository provides access control, audit logging, and vulnerability scanning features. Implemented in: GitHub.
• security control: Automated Build Pipeline - GitHub Actions provides an automated and auditable build pipeline, reducing manual steps and potential for human error. Implemented in: GitHub Actions workflows.
• security control: Static Application Security Testing (SAST) - SAST scanners (e.g., GoSec) are integrated into the build pipeline to automatically detect potential security vulnerabilities in the source code. Implemented in: GitHub Actions workflows, GoSec.
• security control: Dependency Scanning - Dependency scanners are used to identify vulnerabilities in third-party libraries and dependencies. Implemented in: GitHub Actions workflows, Go Modules vulnerability scanning.
• security control: Code Linting - Linters enforce code quality and style guidelines, improving code maintainability and reducing potential for bugs. Implemented in: GitHub Actions workflows, GolangCI-Lint.
• security control: Automated Testing - Automated test suites ensure code functionality and stability, reducing the risk of introducing bugs and vulnerabilities. Implemented in: Go testing framework, GitHub Actions workflows.
• security control: Build Artifact Integrity - Build artifacts are stored with checksums to ensure integrity and prevent tampering. Implemented in: Build scripts, GitHub Actions Artifacts.
• security control: Release Signing (Optional) - Consider signing release binaries to provide authenticity and integrity verification for users.

RISK ASSESSMENT

Critical Business Processes:

• DNS Resolution: Ensuring that domain names resolve to the correct IP addresses, enabling users to access websites and services.
• Service Availability: Maintaining the availability of online services and applications, which depends on correct DNS configuration.
• Brand Reputation: Protecting brand reputation by preventing DNS-related attacks like phishing or domain hijacking.

Data Sensitivity:

• DNS Configuration Data: DNS configuration data itself is generally considered public information. However, the configuration files might contain sensitive information indirectly, such as domain names related to sensitive services or internal infrastructure.
• DNS Provider API Credentials: API credentials used to access DNS providers are highly sensitive. Compromise of these credentials could allow unauthorized modification of DNS records.
• Log Data: Logs may contain information about DNS changes and user actions, which could be sensitive from an audit and security monitoring perspective.

QUESTIONS & ASSUMPTIONS

Questions:

• What is the intended deployment environment for dnscontrol? (e.g., local workstations, CI/CD pipelines, dedicated servers)
• How are DNS provider API credentials currently managed?
• Are there any specific compliance requirements that dnscontrol needs to adhere to?
• What is the expected scale of DNS management using dnscontrol? (number of domains, records, providers)
• Are there any existing security policies or guidelines that need to be considered?

Assumptions:

• BUSINESS POSTURE: The primary business goal is to improve the efficiency, reliability, and security of DNS management. The organization values automation and Infrastructure as Code principles.
• SECURITY POSTURE: Currently, security controls are primarily focused on code review and version control. API credentials are assumed to be managed by users. The organization is concerned about security risks related to DNS management and is willing to invest in improving security controls.
• DESIGN: dnscontrol is primarily used as a CLI tool executed by DevOps engineers or system administrators. Configuration files are stored locally or in version control. Deployment is initially assumed to be local execution on administrator workstations. Build process is automated using GitHub Actions.