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Threat Model Analysis for camunda/camunda-bpm-platform

Threat: Malicious BPMN Deployment (Arbitrary Code Execution)

  • Threat: Malicious BPMN Deployment (Arbitrary Code Execution)

    • Description: An attacker with deployment privileges (or exploiting a vulnerability to gain them) deploys a crafted BPMN 2.0 XML file containing malicious scripts (e.g., in a Script Task) or expressions that execute arbitrary code on the server. The attacker might use known vulnerabilities in the scripting engine or leverage misconfigured service tasks to interact with external systems maliciously.
    • Impact:
      • Complete system compromise.
      • Data exfiltration.
      • Data corruption or deletion.
      • Use of the server for further attacks (e.g., botnet participation).
    • Affected Component:
      • camunda-engine: Process Engine (specifically, the deployment and execution components).
      • Scripting Engine (e.g., camunda-engine-plugin-spin, if Groovy or JavaScript is used).
      • Potentially any service task implementation if misconfigured.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Disable Scripting: If scripting is not absolutely necessary, disable it entirely in the Camunda configuration.
      • Sandboxed Scripting: If scripting is required, use a highly restricted, sandboxed environment. Limit access to system resources, network, and file system. Use a scripting engine with strong security features (e.g., GraalVM JavaScript with restricted context).
      • Input Validation: Validate all inputs to scripts before they are executed. Use whitelisting, not blacklisting.
      • Deployment Authorization: Implement strict role-based access control (RBAC) for process deployment. Only authorized users/groups should be able to deploy.
      • BPMN XML Validation: Implement pre-deployment validation of the BPMN XML. Check for suspicious patterns (e.g., excessive scripting, calls to dangerous APIs). Use static analysis tools.
      • Code Review: Mandatory code review of all BPMN files before deployment, with a focus on security.

Threat: Malicious BPMN Deployment (Resource Exhaustion)

  • Threat: Malicious BPMN Deployment (Resource Exhaustion)

    • Description: An attacker deploys a BPMN process designed to consume excessive resources, leading to a denial-of-service (DoS). This could involve infinite loops, creating a massive number of process instances, or making excessive calls to external services through Camunda service tasks.
    • Impact:
      • Process engine becomes unresponsive.
      • Other applications running on the same server are affected (due to Camunda's resource consumption).
    • Affected Component:
      • camunda-engine: Process Engine (execution, job executor).
    • Risk Severity: High
    • Mitigation Strategies:
      • Rate Limiting: Implement rate limiting on process instance creation and task completion within Camunda's API.
      • Resource Quotas: Configure resource quotas (CPU, memory, execution time) for process instances and tasks within Camunda.
      • Job Executor Tuning: Carefully tune the job executor's configuration (number of threads, queue size) to prevent overload.
      • Process Definition Validation: Check for potential infinite loops or excessive resource usage during pre-deployment validation.
      • Monitoring: Monitor process engine performance and resource usage. Alert on high load.

Threat: External Task Worker Compromise (Impacting Camunda)

  • Threat: External Task Worker Compromise (Impacting Camunda)

    • Description: While the compromise itself is external, the impact is directly on Camunda. A compromised worker returns malicious results to the process engine, corrupting process state or triggering unintended actions within Camunda.
    • Impact:
      • Process corruption (due to malicious results).
      • Bypass of intended process logic.
      • Potential for further attacks within Camunda if the malicious results are used in subsequent steps.
    • Affected Component:
      • camunda-engine: Process Engine (indirectly, through interaction with the compromised worker). The engine processes the malicious data.
    • Risk Severity: High
    • Mitigation Strategies:
      • Authentication & Authorization: Use mutual TLS (mTLS) for secure communication between the engine and workers. This verifies the worker's identity to Camunda.
      • Input Validation & Output Sanitization: Within Camunda, validate all data received from external task workers. Sanitize all data returned to external task workers. This is crucial.
      • Least Privilege (for Workers): Grant workers only the minimum necessary permissions. This limits the external damage, but the focus here is on Camunda's internal handling.

Threat: Privilege Escalation within Camunda Web Applications

  • Threat: Privilege Escalation within Camunda Web Applications

    • Description: A user with limited privileges in Cockpit, Tasklist, or Admin exploits a vulnerability in Camunda's code to gain higher privileges (e.g., becoming an administrator).
    • Impact:
      • Unauthorized access to sensitive data and functionality within Camunda.
      • Ability to deploy malicious processes.
      • Ability to modify user accounts and permissions within Camunda.
    • Affected Component:
      • camunda-webapp: Camunda web applications (Cockpit, Tasklist, Admin).
    • Risk Severity: High
    • Mitigation Strategies:
      • Regular Security Updates: Apply Camunda security patches promptly. This is the primary defense against known vulnerabilities.
      • RBAC Configuration Review: Regularly review and audit the RBAC configuration to ensure it's correctly implemented and enforced within Camunda.
      • Penetration Testing: Conduct regular penetration testing specifically targeting the Camunda web applications.

Threat: Malicious External Task Worker Registration

  • Threat: Malicious External Task Worker Registration

    • Description: An attacker registers a malicious external task worker with the process engine, without proper authorization. This worker then receives tasks intended for legitimate workers.
    • Impact:
      • Interception of sensitive task data.
      • Execution of malicious code within the context of the task.
      • Disruption of process execution.
    • Affected Component:
      • camunda-engine: Process Engine (external task service).
    • Risk Severity: High
    • Mitigation Strategies:
      • Worker Whitelisting: Maintain a list of authorized worker identifiers (e.g., IP addresses, hostnames, or unique IDs). Only allow workers on the whitelist to register and fetch tasks.
      • Authentication: Require strong authentication for worker registration (e.g., API keys, client certificates).