Description: An attacker, by exploiting weak authentication/authorization in Mosquitto or vulnerabilities, gains the ability to publish messages to MQTT topics they should not have access to. They can craft malicious or unintended messages and publish them to disrupt operations or inject false data. Impact: Disruption of application functionality, data corruption, triggering unintended actions in subscribing clients or systems, and potentially causing cascading failures. Mosquitto Component: Authorization module, Message Handling, ACL enforcement. Risk Severity: High Mitigation Strategies: * Implement robust authentication mechanisms in Mosquitto (username/password, TLS client certificates). * Implement fine-grained Access Control Lists (ACLs) in Mosquitto to strictly control publish access based on authenticated user/client and topic. * Regularly review and audit ACL configurations to ensure they are correctly implemented and enforced.
Threat: Connection Flooding (DoS)
Description: An attacker can initiate a large number of connection requests to the Mosquitto broker from a single or distributed source. This can overwhelm the broker's connection handling resources, preventing legitimate clients from connecting and causing a denial of service.
Impact: Broker unavailability, disruption of MQTT-based application functionality, and potential cascading failures in dependent systems.
Mosquitto Component: Network Listener, Connection Handling.
Risk Severity: High
Mitigation Strategies:
* Implement connection limits in Mosquitto configuration using max_connections.
* Implement rate limiting for connection attempts using firewall rules or connection limiting features of the operating system.
* Consider using network intrusion detection/prevention systems (IDS/IPS) to detect and block connection floods targeting the Mosquitto port.
Threat: Message Flooding (DoS)
Description: An attacker, after gaining unauthorized publish access or exploiting vulnerabilities, can publish a massive volume of messages to one or more MQTT topics. This can overwhelm the broker's message processing and queuing capabilities, as well as subscribing clients, leading to performance degradation or denial of service.
Impact: Broker performance degradation, message queue exhaustion, potential crashes of Mosquitto, denial of service for legitimate clients, and disruption of application functionality.
Mosquitto Component: Message Handling, Message Queue, Topic Subscriptions.
Risk Severity: High
Mitigation Strategies:
* Implement message rate limiting in Mosquitto configuration using max_inflight_messages and queue_qos0_messages.
* Implement message size limits in Mosquitto configuration using max_packet_size.
* Implement topic-based access control to restrict publishing and limit the impact of unauthorized publishers.
* Configure appropriate message queue size limits and backpressure mechanisms in Mosquitto to prevent broker overload.
Description: Mosquitto, like any software, may contain security vulnerabilities. Attackers can exploit known vulnerabilities in unpatched versions of Mosquitto to gain unauthorized access, cause denial of service, or execute arbitrary code on the broker server. Impact: Broker compromise, denial of service, potential data breaches, system takeover, and complete loss of control over the MQTT infrastructure. Mosquitto Component: Various components depending on the vulnerability (e.g., parsing, authentication, authorization, network handling). Risk Severity: Critical Mitigation Strategies: * Keep Mosquitto software up-to-date with the latest security patches. Regularly update Mosquitto to the latest stable version. * Regularly monitor security advisories and CVE databases for known vulnerabilities related to Mosquitto. * Implement a vulnerability management process to promptly apply security updates and patches. * Consider using security scanning tools to identify potential vulnerabilities in the Mosquitto installation and its configuration.
Description: Administrators might misconfigure Access Control Lists (ACLs) or use weak or improperly configured authentication methods in Mosquitto. This can inadvertently grant excessive permissions to clients, allowing unauthorized access to topics or bypassing intended security restrictions. Impact: Unauthorized access to MQTT topics, potential for message injection, data theft, disruption of operations, and undermining the intended security posture of the MQTT system. Mosquitto Component: Authentication module, Authorization module, ACL enforcement. Risk Severity: High Mitigation Strategies: * Carefully design and implement ACLs in Mosquitto based on the principle of least privilege. * Regularly review and audit ACL configurations to ensure they are correctly implemented, up-to-date, and effectively enforce intended access controls. * Enforce strong authentication methods in Mosquitto (username/password with strong passwords, TLS client certificates) and ensure they are correctly configured. * Thoroughly test and validate ACL and authentication configurations after implementation and changes to identify potential misconfigurations.