Stack-Based Buffer Overflow in Totolink X2000R Firmware

Executive Summary

This is a stack-based buffer overflow vulnerability in Totolink X2000R firmware version TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327. It exists in the formIpv6Setup functionality where the static_gw parameter is improperly handled. An attacker can send a specially crafted HTTP request to trigger this overflow, potentially leading to arbitrary code execution.

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Detection Guidance

Detecting this vulnerability requires checking for vulnerable Totolink X2000R firmware versions and monitoring HTTP requests targeting the static_gw parameter. Inspect network traffic for malformed IPv6 setup requests to the affected endpoint. Use tools like Wireshark to filter HTTP POST requests to /cgi-bin/formIpv6Setup.cgi with unusually long static_gw values.

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Impact Analysis

If exploited, this vulnerability allows an attacker to execute arbitrary code on the affected device. This could lead to unauthorized access, data theft, or complete device compromise. The attacker needs authenticated HTTP access, which may require prior compromise of credentials or session tokens.

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Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating confidentiality requirements in GDPR and HIPAA. If the device handles personal or health data, exploitation may result in non-compliance with these regulations, potentially leading to legal penalties and reputational damage.

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Mitigation Strategies

Immediately update the Totolink X2000R firmware to the latest patched version. Disable IPv6 static network configuration if not required. Restrict access to the /cgi-bin/formIpv6Setup.cgi endpoint via network segmentation or firewall rules. Monitor for suspicious HTTP requests targeting this endpoint.

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