CVE-2024-30595: Tenda FH1202 Buffer Overflow Vulnerability

CVE-2024-30595 Overview

CVE-2024-30595 is a stack overflow vulnerability affecting the Tenda FH1202 wireless router firmware version 1.2.0.14(408). The vulnerability exists in the deviceId parameter of the addWifiMacFilter function, which fails to properly validate input length before copying data to a stack-based buffer. This flaw allows remote attackers to potentially execute arbitrary code or cause a denial of service condition on affected devices.

Critical Impact

This stack overflow vulnerability can be exploited remotely without authentication, potentially allowing attackers to gain complete control of affected Tenda FH1202 routers or render them inoperable.

Affected Products

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

Discovery Timeline

• 2024-03-28 - CVE-2024-30595 published to NVD
• 2025-03-13 - Last updated in NVD database

Technical Details for CVE-2024-30595

Vulnerability Analysis

The vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption issue that occurs when the addWifiMacFilter function processes user-supplied data through the deviceId parameter. The function lacks proper bounds checking when handling input, allowing an attacker to supply a specially crafted deviceId value that exceeds the allocated buffer size on the stack.

When exploited, the overflow can overwrite critical stack data including the return address, potentially allowing an attacker to redirect program execution to attacker-controlled code. As a network-accessible vulnerability requiring no authentication or user interaction, this represents a significant risk to any exposed Tenda FH1202 devices.

Root Cause

The root cause of this vulnerability lies in the improper input validation within the addWifiMacFilter function. The function accepts the deviceId parameter without verifying its length against the destination buffer capacity. When a malicious actor provides an oversized input, the data overflows the stack buffer, corrupting adjacent memory regions including saved registers and return addresses.

Attack Vector

The vulnerability is exploitable remotely over the network. An attacker can craft a malicious HTTP request to the router's web management interface, targeting the addWifiMacFilter endpoint with an oversized deviceId parameter. Since no authentication is required and no user interaction is needed, the attack can be carried out against any exposed Tenda FH1202 device running the vulnerable firmware version.

The attack flow typically involves:

1. Identifying a vulnerable Tenda FH1202 device on the network
2. Crafting an HTTP request to the addWifiMacFilter function with an oversized deviceId parameter
3. The malformed input triggers the stack overflow, corrupting the stack frame
4. Depending on the attacker's payload, this can result in arbitrary code execution or denial of service

For detailed technical analysis of this vulnerability, see the GitHub IoT Vulnerability Analysis.

Detection Methods for CVE-2024-30595

Indicators of Compromise

• Unexpected router reboots or crashes indicating potential exploitation attempts
• Unusual network traffic patterns to/from the router's management interface
• Modified router configurations or firmware settings that were not authorized
• Presence of unfamiliar processes or services running on the device

Detection Strategies

• Monitor HTTP requests to the router's web interface for abnormally long deviceId parameter values
• Implement network-based intrusion detection rules to identify stack overflow exploitation patterns
• Deploy web application firewall rules to filter requests with oversized parameters to router endpoints
• Regularly audit router firmware versions against known vulnerable releases

Monitoring Recommendations

• Enable logging on network perimeter devices to capture traffic to router management interfaces
• Set up alerts for multiple failed or malformed requests to the addWifiMacFilter endpoint
• Monitor for unexpected changes to router configurations or credentials
• Implement network segmentation to isolate IoT devices and limit exposure

How to Mitigate CVE-2024-30595

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 Tenda FH1202 behind a properly configured firewall
• Consider replacing affected devices with hardware that receives regular security updates

Patch Information

As of the last update, no official vendor patch has been publicly documented for this vulnerability. Users should monitor Tenda's official support channels for firmware updates. Given the critical nature of this vulnerability and the lack of available patches, organizations should prioritize implementing compensating controls and consider device replacement.

Workarounds

• Disable remote web management access to prevent external exploitation
• Implement network access control lists (ACLs) to restrict management interface access
• Use a VPN or jump host for administrative access to network equipment
• Deploy network-level filtering to block requests with oversized parameters

# Example iptables rule to restrict access to router management interface
# Replace 192.168.1.1 with your router's IP and adjust trusted IP range
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP
iptables -A INPUT -s 10.0.0.0/24 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT