Executive Summary

This vulnerability is a missing authorization flaw in certain Zyxel GS1200v3 series switches. It allows an attacker who is on the local network and does not have to authenticate to the device to read the system configuration by sending a specially crafted HTTP request. Essentially, the attacker can access sensitive configuration information from a log file without proper permission.

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Impact Analysis

The impact of this vulnerability is that an unauthenticated attacker on the local network can gain access to the system configuration of the affected Zyxel switches. This could expose sensitive network settings and information, potentially allowing the attacker to understand the network setup and plan further attacks or disruptions.

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Detection Guidance

This vulnerability can be detected by checking if your Zyxel GS1200v3 series switch is running an affected firmware version (1.00(ACPS.2)C0 or earlier for GS1200-5v3, 1.00(ACPT.2)C0 or earlier for GS1200-8v3, 1.00(ACPU.2)C0 or earlier for GS1200-5HPv3, 1.00(ACPV.2)C0 or earlier for GS1200-8HPv3, and 1.00(ACPW.2)C0 or earlier for GS1200-10v3).

To detect exploitation attempts, monitor HTTP requests on the local network for unusual or crafted requests targeting the switch that might attempt to access log files or configuration data without authentication.

Specific commands are not provided in the advisory, but you can use network monitoring tools such as tcpdump or Wireshark to capture HTTP traffic to the switch's IP address and look for suspicious GET requests that might be crafted to read system configuration.

• Example tcpdump command to capture HTTP traffic to the switch: tcpdump -i <interface> host <switch_ip> and port 80
• Use Wireshark to filter HTTP requests and inspect for unusual URLs or parameters that could indicate an attempt to exploit the vulnerability.

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Mitigation Strategies

The immediate step to mitigate this vulnerability is to update the firmware of your Zyxel GS1200v3 series switch to the latest version released by Zyxel that patches this missing authorization issue.

Additionally, restrict access to the management interface of the switch to trusted LAN segments only, and monitor network traffic for suspicious HTTP requests targeting the device.

Contact Zyxel support or your local service representative for assistance with firmware updates and further security recommendations.

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Compliance Impact

This vulnerability allows an unauthenticated attacker on the local network to read system configuration data from a log file, which could potentially expose sensitive information.

Exposure of sensitive configuration data may lead to non-compliance with data protection regulations such as GDPR or HIPAA, which require adequate protection of personal and sensitive information.

Organizations using affected Zyxel GS1200v3 series switches should apply the provided patches promptly to mitigate the risk and maintain compliance with these standards.

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