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sec-design.md

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BUSINESS POSTURE

Business Priorities and Goals:

  • Provide a highly available and scalable database solution.
  • Offer a decentralized, fault-tolerant architecture for mission-critical data.
  • Support high-volume, high-velocity data ingestion and retrieval.
  • Provide a flexible data model (schema-optional) that can adapt to evolving application needs.
  • Maintain a strong open-source community and ecosystem.
  • Offer tunable consistency levels to meet different application requirements.
  • Minimize operational overhead and administrative burden.

Most Important Business Risks:

  • Data loss or corruption due to hardware failures, software bugs, or operational errors.
  • Service unavailability leading to application downtime and business disruption.
  • Unauthorized data access or modification due to security vulnerabilities.
  • Performance degradation or bottlenecks impacting application responsiveness.
  • Inability to scale to meet growing data volume and user demand.
  • Complexity of management and configuration leading to operational errors.
  • Lack of skilled personnel to manage and maintain the Cassandra cluster.

SECURITY POSTURE

Existing Security Controls:

  • security control: Authentication: Cassandra supports multiple authentication mechanisms, including internal authentication (using passwords), LDAP, and Kerberos. This is described in the Cassandra documentation and configuration files.
  • security control: Authorization: Cassandra provides role-based access control (RBAC) to manage permissions on database objects (keyspaces, tables, etc.). This is managed through Cassandra's GRANT and REVOKE commands and roles management.
  • security control: Client-to-node encryption: Cassandra supports TLS/SSL encryption for communication between clients and Cassandra nodes. Configuration details are in cassandra.yaml.
  • security control: Node-to-node encryption: Cassandra supports TLS/SSL encryption for inter-node communication. Configuration details are in cassandra.yaml.
  • security control: JMX access control: Cassandra uses JMX for management and monitoring. Access to JMX can be secured using password authentication and SSL.
  • security control: Auditing: Cassandra can be configured to log various events, including authentication successes and failures, schema changes, and permission changes. This is configured in cassandra.yaml and related audit logging configuration files.
  • security control: Transparent Data Encryption (TDE): DSE (DataStax Enterprise, a commercial distribution) offers TDE, but the open-source Apache Cassandra project does not natively support encryption at rest. Users often rely on OS-level or disk-level encryption.

Accepted Risks:

  • accepted risk: Lack of native encryption at rest in Apache Cassandra. This means data stored on disk is not encrypted by default in the open-source version. Mitigation often relies on external tools or operating system features.
  • accepted risk: Potential for misconfiguration of security features. Cassandra's security features require careful configuration. Mistakes can lead to vulnerabilities.
  • accepted risk: Complexity of managing a distributed database. Cassandra's distributed nature introduces complexities in security management, requiring expertise to configure and maintain securely.

Recommended Security Controls:

  • security control: Implement OS-level or disk-level encryption to provide encryption at rest. This mitigates the accepted risk of no native encryption at rest.
  • security control: Regularly review and update Cassandra configurations, especially security-related settings, to address potential misconfigurations.
  • security control: Implement a robust monitoring and alerting system to detect and respond to security incidents promptly.
  • security control: Conduct regular security audits and penetration testing to identify and address vulnerabilities.
  • security control: Use a dedicated, secured network segment for inter-node communication.
  • security control: Implement strong password policies and regularly rotate credentials.

Security Requirements:

  • Authentication:
    • All client connections must be authenticated.
    • Support for strong authentication mechanisms (e.g., Kerberos, LDAP).
    • Enforce password complexity and rotation policies.
  • Authorization:
    • Implement granular access control using RBAC.
    • Follow the principle of least privilege.
    • Regularly review and audit user permissions.
  • Input Validation:
    • While Cassandra itself doesn't directly handle "input" in the same way as a web application, data types are enforced at the schema level. Ensure appropriate data types are used to prevent injection-like attacks at the application level.
    • Applications interacting with Cassandra should perform input validation to prevent malicious data from being stored.
  • Cryptography:
    • Use TLS/SSL for all client-to-node and node-to-node communication.
    • Use strong cipher suites and regularly update TLS/SSL configurations.
    • If using OS-level or disk-level encryption, use strong encryption algorithms (e.g., AES-256).

DESIGN

C4 CONTEXT

graph LR
    subgraph Cassandra System
        Cassandra["Cassandra Cluster"]
    end
    User["Users/Applications"] --> Cassandra
    Admin["Administrators"] --> Cassandra
    Monitoring["Monitoring Systems"] --> Cassandra
    Backup["Backup Systems"] --> Cassandra
    ExternalSystems["External Systems (LDAP, Kerberos)"] --> Cassandra
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Element Descriptions:

  • Element:

    • Name: Cassandra Cluster
    • Type: System
    • Description: The distributed database system itself, comprising multiple nodes.
    • Responsibilities: Storing data, processing queries, ensuring data consistency and availability.
    • Security controls: Authentication, authorization, client-to-node encryption, node-to-node encryption, JMX access control, auditing.

  • Element:

    • Name: Users/Applications
    • Type: User
    • Description: Applications or users that interact with the Cassandra cluster to store and retrieve data.
    • Responsibilities: Sending requests to Cassandra, processing responses.
    • Security controls: Authenticate to Cassandra, use secure communication channels (TLS/SSL).

  • Element:

    • Name: Administrators
    • Type: User
    • Description: Individuals responsible for managing and maintaining the Cassandra cluster.
    • Responsibilities: Configuring Cassandra, monitoring performance, performing backups, managing security.
    • Security controls: Authenticate to Cassandra with strong credentials, use secure communication channels, adhere to the principle of least privilege.

  • Element:

    • Name: Monitoring Systems
    • Type: System
    • Description: Systems that collect metrics and logs from the Cassandra cluster for performance monitoring and troubleshooting.
    • Responsibilities: Collecting data from Cassandra, providing dashboards and alerts.
    • Security controls: Secure communication with Cassandra (e.g., using JMX over SSL), access control to monitoring data.

  • Element:

    • Name: Backup Systems
    • Type: System
    • Description: Systems used to create and restore backups of the Cassandra data.
    • Responsibilities: Creating backups, storing backups securely, restoring backups when needed.
    • Security controls: Secure communication with Cassandra, secure storage of backup data (encryption), access control to backup systems.

  • Element:

    • Name: External Systems (LDAP, Kerberos)
    • Type: System
    • Description: External systems used for authentication and authorization.
    • Responsibilities: Authenticating users, providing authorization information.
    • Security controls: Secure communication with Cassandra, secure configuration of LDAP/Kerberos.

C4 CONTAINER

Since Cassandra is a single, albeit distributed, application, the container diagram is essentially an expanded view of the context diagram, focusing on the internal components of a Cassandra node.

graph LR
    subgraph Cassandra Node
        Client["Client Connections"] --> RequestHandler["Request Handler"]
        RequestHandler --> StorageEngine["Storage Engine"]
        StorageEngine --> CommitLog["Commit Log"]
        StorageEngine --> Memtable["Memtable"]
        Memtable --> SSTable["SSTable"]
        StorageEngine --> SSTable
        Gossip["Gossip Protocol"]
    end
    ClientConnections["Client Connections"]
    subgraph Other Cassandra Nodes
      OtherNode["Other Cassandra Node"]
    end
    Gossip <--> OtherNode
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Element Descriptions:

  • Element:

    • Name: Client Connections
    • Type: Container
    • Description: Handles incoming connections from clients.
    • Responsibilities: Accepting connections, authenticating clients, routing requests.
    • Security controls: Authentication (using configured mechanisms), TLS/SSL encryption.

  • Element:

    • Name: Request Handler
    • Type: Container
    • Description: Processes client requests (reads and writes).
    • Responsibilities: Parsing requests, coordinating with the storage engine, returning results.
    • Security controls: Authorization (checking permissions).

  • Element:

    • Name: Storage Engine
    • Type: Container
    • Description: Manages data storage and retrieval.
    • Responsibilities: Writing data to the commit log and memtable, flushing memtables to SSTables, reading data from SSTables.
    • Security controls: None directly, relies on OS-level security and file permissions.

  • Element:

    • Name: Commit Log
    • Type: Container
    • Description: A persistent log of all write operations.
    • Responsibilities: Ensuring data durability in case of crashes.
    • Security controls: None directly, relies on OS-level security and file permissions.

  • Element:

    • Name: Memtable
    • Type: Container
    • Description: An in-memory data structure that buffers writes.
    • Responsibilities: Storing recent writes, providing fast read access to recent data.
    • Security controls: None directly.

  • Element:

    • Name: SSTable
    • Type: Container
    • Description: Sorted String Tables - immutable data files on disk.
    • Responsibilities: Storing data persistently.
    • Security controls: None directly in open-source Cassandra, relies on OS-level security and file permissions. DSE can use TDE.

  • Element:

    • Name: Gossip Protocol
    • Type: Container
    • Description: A peer-to-peer communication protocol used for node discovery and cluster management.
    • Responsibilities: Sharing node status information, detecting failures.
    • Security controls: Node-to-node encryption (TLS/SSL).

  • Element:

    • Name: Other Cassandra Node
    • Type: Container
    • Description: Represents another node in Cassandra cluster.
    • Responsibilities: Same as Cassandra Node.
    • Security controls: Same as Cassandra Node.

DEPLOYMENT

Cassandra can be deployed in various ways:

  1. Bare Metal: Directly on physical servers.
  2. Virtual Machines: On VMs in a private or public cloud.
  3. Containers (e.g., Docker): Within containers, often orchestrated by Kubernetes.
  4. Cloud Provider Managed Services: Using managed Cassandra offerings like Amazon Keyspaces or Azure Cosmos DB for Apache Cassandra.

We'll describe deployment using Kubernetes, as it's a common and robust approach.

graph LR
    subgraph Kubernetes Cluster
        subgraph Namespace (cassandra)
            CassandraPod1["Cassandra Pod 1"]
            CassandraPod2["Cassandra Pod 2"]
            CassandraPod3["Cassandra Pod 3"]
            Storage1["Persistent Volume 1"]
            Storage2["Persistent Volume 2"]
            Storage3["Persistent Volume 3"]
            Service["Cassandra Service"]
        end
        Ingress["Ingress Controller"] --> Service
    end
    Client["Client Application"] --> Ingress
    CassandraPod1 --> Storage1
    CassandraPod2 --> Storage2
    CassandraPod3 --> Storage3
    CassandraPod1 <--> CassandraPod2
    CassandraPod1 <--> CassandraPod3
    CassandraPod2 <--> CassandraPod3
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Element Descriptions:

  • Element:

    • Name: Kubernetes Cluster
    • Type: Deployment Environment
    • Description: The Kubernetes cluster where Cassandra is deployed.
    • Responsibilities: Orchestrating containers, managing resources, providing networking.
    • Security controls: Kubernetes RBAC, network policies, pod security policies, secrets management.

  • Element:

    • Name: Namespace (cassandra)
    • Type: Logical Grouping
    • Description: A Kubernetes namespace dedicated to the Cassandra deployment.
    • Responsibilities: Isolating Cassandra resources from other applications.
    • Security controls: Network policies to restrict traffic to/from the namespace.

  • Element:

    • Name: Cassandra Pod (1, 2, 3)
    • Type: Container Instance
    • Description: A Kubernetes pod running a Cassandra container.
    • Responsibilities: Running a single instance of the Cassandra database.
    • Security controls: Container image security (scanning for vulnerabilities), resource limits, pod security context.

  • Element:

    • Name: Persistent Volume (1, 2, 3)
    • Type: Storage
    • Description: Persistent storage for each Cassandra pod.
    • Responsibilities: Providing durable storage for Cassandra data.
    • Security controls: Encryption at rest (if supported by the storage provider), access controls on the storage.

  • Element:

    • Name: Cassandra Service
    • Type: Service
    • Description: A Kubernetes service that provides a stable endpoint for accessing the Cassandra cluster.
    • Responsibilities: Load balancing traffic across Cassandra pods.
    • Security controls: Network policies to control access to the service.

  • Element:

    • Name: Ingress Controller
    • Type: Load Balancer
    • Description: An ingress controller that manages external access to the Cassandra service.
    • Responsibilities: Routing external traffic to the Cassandra service.
    • Security controls: TLS termination, access control rules.

  • Element:

    • Name: Client Application
    • Type: External Application
    • Description: An application outside the Kubernetes cluster that connects to Cassandra.
    • Responsibilities: Interacting with the Cassandra database.
    • Security controls: Authenticate to Cassandra, use secure communication (TLS).

BUILD

Cassandra's build process is managed through Apache Maven. The source code is hosted on GitHub, and continuous integration is likely performed using Jenkins (based on historical information; the Apache project uses a variety of tools, and specifics can change).

graph LR
    Developer["Developer"] --> GitHub["GitHub (Source Code)"]
    GitHub --> Jenkins["Jenkins (CI Server)"]
    Jenkins --> Maven["Maven (Build Tool)"]
    Maven --> UnitTests["Unit Tests"]
    Maven --> IntegrationTests["Integration Tests"]
    Maven --> SAST["SAST (Static Analysis)"]
    Maven --> ArtifactRepo["Artifact Repository (e.g., Apache Nexus)"]
    ArtifactRepo --> CassandraRelease["Cassandra Release (tarball, deb, rpm)"]
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Build Process Security Controls:

  • security control: Source Code Management: GitHub provides access control, code review mechanisms, and branch protection rules.
  • security control: Build Automation: Jenkins automates the build process, ensuring consistency and repeatability.
  • security control: Dependency Management: Maven manages dependencies, but it's crucial to use tools like OWASP Dependency-Check to identify and mitigate vulnerabilities in third-party libraries.
  • security control: Static Analysis (SAST): SAST tools (e.g., FindBugs, SpotBugs, SonarQube) can be integrated into the Maven build process to identify potential security vulnerabilities in the code.
  • security control: Unit and Integration Tests: Comprehensive tests help ensure the correctness and security of the code.
  • security control: Artifact Repository: A secure artifact repository (e.g., Apache Nexus) is used to store and manage build artifacts. Access control and integrity checks are important.
  • security control: Supply Chain Security: While not explicitly shown in the diagram, efforts are ongoing in the open-source community to improve supply chain security, including signing releases and providing SBOMs (Software Bill of Materials).

RISK ASSESSMENT

Critical Business Processes:

  • Data storage and retrieval for applications relying on Cassandra.
  • Real-time data processing and analytics (if applicable).
  • Maintaining high availability and fault tolerance for mission-critical applications.

Data Sensitivity:

  • The sensitivity of the data stored in Cassandra depends entirely on the applications using it. Cassandra itself doesn't inherently know the sensitivity of the data.
  • Data sensitivity can range from non-sensitive (e.g., public data) to highly sensitive (e.g., PII, financial data, healthcare data).
  • Applications using Cassandra are responsible for classifying and protecting data appropriately, using techniques like encryption and access control.

QUESTIONS & ASSUMPTIONS

Questions:

  • What specific compliance requirements (e.g., GDPR, HIPAA, PCI DSS) apply to the applications using Cassandra? This will influence the necessary security controls.
  • What are the specific performance and scalability requirements for the Cassandra cluster?
  • What is the expected data volume and growth rate?
  • What are the existing security policies and procedures within the organization?
  • What level of expertise is available for managing and maintaining Cassandra?
  • Are there any specific external systems (besides LDAP/Kerberos) that Cassandra needs to integrate with?
  • What is the specific CI/CD pipeline used for building and deploying Cassandra (confirming Jenkins usage and details)?
  • What specific SAST/DAST tools are used, if any?
  • What is the process for vulnerability management and patching?

Assumptions:

  • BUSINESS POSTURE: The organization prioritizes data availability and scalability, but also recognizes the importance of data security.
  • SECURITY POSTURE: The organization has a basic understanding of security best practices and is willing to invest in necessary security controls.
  • DESIGN: The deployment will use Kubernetes, and the build process will leverage Maven and a CI/CD system (assumed to be Jenkins). The organization will implement OS-level or disk-level encryption to compensate for the lack of native encryption at rest in open-source Cassandra.