CVE-2024-30596: Tenda FH1202 Buffer Overflow Vulnerability

CVE-2024-30596 Overview

CVE-2024-30596 is a critical stack overflow vulnerability affecting the Tenda FH1202 wireless router. The vulnerability exists in the deviceId parameter of the formSetDeviceName function in firmware version 1.2.0.14(408). This flaw allows remote attackers to execute arbitrary code or cause denial of service conditions on affected devices without requiring authentication.

Critical Impact

Remote attackers can exploit this stack overflow vulnerability to execute arbitrary code, potentially gaining full control of the affected router or causing device instability through network-based attacks.

Affected Products

• Tenda FH1202 Hardware Device
• Tenda FH1202 Firmware version 1.2.0.14(408)

Discovery Timeline

• 2024-03-28 - CVE-2024-30596 published to NVD
• 2025-03-13 - Last updated in NVD database

Technical Details for CVE-2024-30596

Vulnerability Analysis

This vulnerability is a classic stack-based buffer overflow in embedded router firmware. The formSetDeviceName function fails to properly validate the length of user-supplied input in the deviceId parameter before copying it to a fixed-size stack buffer. When an attacker sends an oversized deviceId value, it overwrites adjacent stack memory, including the saved return address.

The vulnerability is particularly dangerous because it can be triggered remotely over the network without any authentication. IoT devices like the Tenda FH1202 often run with elevated privileges, meaning successful exploitation could provide complete control over the device. The affected function handles device naming operations, which is accessible through the router's web management interface.

Root Cause

The root cause is improper input validation in the formSetDeviceName function. The function uses an unsafe string copy operation that does not check the boundary of the destination buffer before copying the deviceId parameter. This allows attacker-controlled data to overflow the stack buffer and corrupt adjacent memory regions, including function return addresses and saved frame pointers.

Attack Vector

The attack can be executed remotely over the network. An attacker with network access to the router's management interface can craft a malicious HTTP request containing an oversized deviceId parameter. When the formSetDeviceName function processes this request, the stack buffer overflows, allowing the attacker to control program execution flow. No authentication is required, and no user interaction is needed for successful exploitation.

The exploitation process involves sending a specially crafted request to the device's web interface with an oversized deviceId value designed to overwrite the return address on the stack with attacker-controlled data. For detailed technical analysis of the vulnerability, refer to the GitHub IoT Vulnerability Document.

Detection Methods for CVE-2024-30596

Indicators of Compromise

• Unexpected router reboots or crashes that may indicate exploitation attempts
• Unusual outbound network connections from the router to unknown IP addresses
• Modified router configurations or unauthorized administrative changes
• Anomalous HTTP requests to the router's web management interface with unusually long parameter values

Detection Strategies

• Monitor network traffic for HTTP requests to the router's management interface containing abnormally large deviceId parameters
• Implement intrusion detection rules to flag requests exceeding normal parameter lengths for the formSetDeviceName endpoint
• Deploy network segmentation to isolate IoT devices and monitor traffic patterns for anomalies
• Review router logs for repeated access attempts or error conditions related to device naming functions

Monitoring Recommendations

• Enable logging on network firewalls to capture all traffic to and from the affected router
• Implement network monitoring solutions to detect unusual patterns of communication from IoT devices
• Consider deploying honeypot devices to detect scanning activity targeting Tenda routers
• Regularly audit router configurations to detect unauthorized changes

How to Mitigate CVE-2024-30596

Immediate Actions Required

• Restrict network access to the router's web management interface to trusted IP addresses only
• Disable remote management features if not required for operations
• Place the router behind a firewall that can filter malicious requests
• Monitor for firmware updates from Tenda and apply patches when available

Patch Information

As of the last update on 2025-03-13, no vendor advisory or official patch has been published by Tenda for this vulnerability. Organizations should monitor Tenda's official support channels for firmware updates addressing CVE-2024-30596. Consider replacing vulnerable devices with supported alternatives if no patch becomes available.

Workarounds

• Implement network access controls to limit who can reach the router's management interface
• Use a VPN or out-of-band management network for administrative access
• Disable the web management interface entirely if alternative management methods are available
• Deploy a web application firewall in front of the router to filter requests with oversized parameters

# Example iptables rule to restrict management interface access
# Allow only trusted subnet to access router management
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP