Argument Injection in Cudy TR3000 Firmware

Executive Summary

Cudy TR3000 before version 2.5.42 has an argument injection flaw in the easycwmpd Upload handler. This allows a malicious or compromised ACS to inject curl options via unfiltered Username and Password fields. Attackers can use whitespace to add options like -o and --url, enabling them to write arbitrary HTTP responses to any file on the device.

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Detection Guidance

To detect this vulnerability, inspect Cudy TR3000 devices running firmware versions before 2.5.42 for unusual curl command execution patterns or unexpected file writes. Check logs for Upload handler activity with malformed Username or Password fields containing whitespace or curl options like -o or --url.

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Impact Analysis

This vulnerability could allow attackers to overwrite critical system files on the device by injecting malicious curl commands. This may lead to unauthorized code execution, data theft, or device compromise, potentially disrupting network operations or exposing sensitive information.

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Mitigation Strategies

Immediately update Cudy TR3000 devices to firmware version 2.5.42 or later. If an update is not immediately available, restrict access to the Upload handler and monitor for suspicious activity. Disable unnecessary services and review network traffic for signs of exploitation.

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