Skip to content

Latest commit

 

History

History
49 lines (40 loc) · 4.5 KB

attack-surface.md

File metadata and controls

49 lines (40 loc) · 4.5 KB

Attack Surface Analysis for eclipse-mosquitto/mosquitto

Attack Surface: Unauthenticated Access

  • Description: Clients connecting to the broker without providing any credentials.
  • Mosquitto Contribution: Mosquitto's allow_anonymous setting directly controls whether unauthenticated connections are permitted. Defaults may vary, making this a critical check.
  • Example: An attacker connects without credentials and subscribes to all topics (#).
  • Impact: Complete compromise of the MQTT system; read/publish to all topics.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Disable Anonymous Access: Explicitly set allow_anonymous false in mosquitto.conf.
    • Require Authentication: Enforce username/password or client certificate authentication.

Attack Surface: Unencrypted Communication (Plaintext MQTT)

  • Description: Data transmitted without TLS encryption.
  • Mosquitto Contribution: Mosquitto supports both encrypted and unencrypted listeners. The configuration determines which are active. The presence of an active listener 1883 without TLS is the direct vulnerability.
  • Example: An attacker captures network traffic and sees MQTT messages in plain text.
  • Impact: Complete data exposure; eavesdropping and potential Man-in-the-Middle attacks.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Disable Plaintext Listener: Comment out or remove any listener 1883 (or any unencrypted listener) configuration in mosquitto.conf.
    • Enable and Enforce TLS: Configure a listener 8883 with a valid certificate and key. Ensure clients use TLS.

Attack Surface: Weak Authentication/Authorization

  • Description: Easily guessable passwords, default credentials, or overly permissive Access Control Lists (ACLs).
  • Mosquitto Contribution: Mosquitto's authentication mechanisms (password file, plugins) and its ACL system (acl_file or plugin-based ACLs) are the direct points of vulnerability if misconfigured.
  • Example: An attacker brute-forces a weak password, or an ACL grants a client excessive topic access.
  • Impact: Unauthorized access; the extent depends on the compromised client's privileges and the ACL configuration.
  • Risk Severity: High
  • Mitigation Strategies:
    • Strong Passwords: Enforce strong password policies.
    • Secure Authentication: Use robust authentication methods (database, LDAP, or a well-vetted plugin). Avoid the default password file if possible.
    • Principle of Least Privilege (ACLs): Meticulously configure ACLs to grant only the necessary topic access to each client. Regularly audit ACLs.

Attack Surface: Denial-of-Service (DoS) - Mosquitto-Specific

  • Description: Attacks targeting Mosquitto's resource handling to make it unavailable. This focuses on attacks exploiting Mosquitto's internal handling, not general network floods.
  • Mosquitto Contribution: Mosquitto's internal handling of connections, message queues, and memory allocation can be targeted. Specific configuration options like max_connections, max_queued_messages, and memory_limit (if available) directly influence susceptibility.
  • Example: An attacker sends a large number of connection requests within the limits of a general network flood, but crafted to exploit how Mosquitto handles connection establishment internally. Or, they send many small, persistent connections to exhaust file descriptors.
  • Impact: Broker unavailability; legitimate clients cannot connect or communicate.
  • Risk Severity: High
  • Mitigation Strategies:
    • Connection Limits: Use max_connections in mosquitto.conf appropriately.
    • Mosquitto-Specific Rate Limiting: If available (through per_listener_settings or plugins), implement rate limiting specifically within Mosquitto to control message frequency per client. This is distinct from general network rate limiting.
    • Resource Limits (Mosquitto-Specific): If Mosquitto provides options like memory_limit or similar resource controls, use them judiciously.
    • Keep Updated: Newer Mosquitto versions often include performance and robustness improvements that mitigate DoS vectors.