Executive Summary

This vulnerability is a buffer overflow in the Shenzhen Libituo Technology LBT-T300-HW1 router, specifically in the function start_lan within the /apply.cgi file. It occurs when the argument Channel/ApCliSsid is manipulated with an excessively long input, causing a stack overflow. The vulnerability can be exploited remotely by sending a crafted HTTP POST request to the router's apply.cgi endpoint with a maliciously long Channel parameter.

The overflow happens because the router's wireless LAN configuration process improperly handles the Channel variable, which is passed from the web interface via the nvram_get function. This can lead to arbitrary command execution on the device.

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Impact Analysis

This vulnerability can have serious impacts as it allows a remote attacker to cause a buffer overflow on the affected router, potentially leading to arbitrary command execution. This means an attacker could take control of the device, disrupt network services, intercept or manipulate network traffic, or use the device as a foothold for further attacks within the network.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious HTTP POST requests sent to the router's /apply.cgi endpoint that contain an excessively long Channel parameter.

Specifically, detection involves identifying requests where the Channel or ApCliSsid argument is manipulated with an unusually long string (e.g., 512 characters of '1'), which triggers the buffer overflow.

A practical approach is to capture and analyze network traffic targeting the router's web interface, looking for POST requests with a large payload in the Channel parameter.

• Use a network packet capture tool like tcpdump or Wireshark to filter HTTP POST requests to /apply.cgi.
• Example tcpdump command to capture relevant traffic: tcpdump -i <interface> -A 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)'
• Inspect captured HTTP POST payloads for the presence of a Channel parameter with an abnormally long value.
• Alternatively, use curl or similar tools to send crafted requests to test if the device is vulnerable by sending a POST request with a long Channel parameter to /apply.cgi.

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Mitigation Strategies

Immediate mitigation steps include restricting access to the router's web interface to trusted networks or IP addresses to prevent remote exploitation.

Disable remote management features if enabled, to reduce exposure.

Monitor network traffic for suspicious POST requests targeting /apply.cgi with unusually long Channel parameters and block such requests if possible.

If available, apply any vendor patches or firmware updates addressing this vulnerability; however, the vendor has not responded to the disclosure.

As a temporary workaround, consider using network-level protections such as firewalls or intrusion prevention systems to detect and block exploit attempts.

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Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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