Incorrect Access Control in TOTOLINK T6 Firmware

Executive Summary

This vulnerability is an incorrect access control issue in the TOTOLINK T6 router firmware version 4.1.5cu.748_B20211015. It allows unauthenticated attackers to manipulate the primary mesh channel by sending a specially crafted MQTT message to the cs_broker component, enabling them to rescan and switch channels without proper authorization.

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Detection Guidance

Detecting this vulnerability requires monitoring MQTT traffic for unauthorized cs_broker messages. Check for unexpected channel rescan or switch commands sent to TOTOLINK T6 devices. Use network sniffers like tcpdump or Wireshark to capture MQTT traffic on port 1883 or 8883. Look for messages targeting the cs_broker component with payloads attempting to modify the primary mesh channel.

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Impact Analysis

An attacker could exploit this to disrupt network communications by changing the primary mesh channel, potentially causing connectivity issues or unauthorized network access. This may lead to data interception or network instability for users relying on the TOTOLINK T6 device.

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Compliance Impact

This vulnerability allows unauthenticated attackers to manipulate the primary mesh channel via crafted MQTT messages, which could lead to unauthorized access or control of network traffic. Such unauthorized access may violate data protection requirements under GDPR (e.g., unauthorized data processing) and HIPAA (e.g., unauthorized access to protected health information).

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Mitigation Strategies

Immediately isolate affected TOTOLINK T6 devices from untrusted networks. Disable MQTT access to the cs_broker component if possible. Update the device firmware if a patch is available. Monitor device logs for suspicious MQTT activity and restrict network access to the device's management interface.

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