CVE-2024-30589: Tenda FH1202 Buffer Overflow Vulnerability

CVE-2024-30589 Overview

CVE-2024-30589 is a stack overflow vulnerability affecting the Tenda FH1202 wireless router firmware version 1.2.0.14(408). The vulnerability exists in the entrys parameter of the fromAddressNat function, which fails to properly validate user-supplied input before copying it to a fixed-size stack buffer. This memory corruption flaw can be exploited remotely without authentication, potentially allowing attackers to execute arbitrary code or cause denial of service on affected devices.

Critical Impact

Remote attackers can exploit this stack overflow vulnerability to potentially gain complete control of the affected Tenda FH1202 router, compromising network security and enabling further attacks on connected devices.

Affected Products

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

Discovery Timeline

• 2024-03-28 - CVE-2024-30589 published to NVD
• 2025-03-13 - Last updated in NVD database

Technical Details for CVE-2024-30589

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption issue where user-controlled data exceeds the boundaries of a stack-allocated buffer. The fromAddressNat function in the Tenda FH1202 firmware processes the entrys parameter without adequate bounds checking, allowing an attacker to overwrite adjacent stack memory including the function's return address.

The vulnerability is accessible over the network without requiring authentication, making it particularly dangerous in typical deployment scenarios where these routers are exposed to the internet or untrusted local networks. Successful exploitation could result in complete compromise of the router's confidentiality, integrity, and availability.

Root Cause

The root cause lies in unsafe memory operations within the fromAddressNat function. The firmware fails to validate the length of the entrys parameter before copying it into a fixed-size stack buffer. This lack of input validation allows attackers to provide oversized input that overwrites the stack frame, including saved registers and the return address.

Stack-based buffer overflows in embedded devices like routers are particularly severe because these devices often lack modern exploit mitigations such as Address Space Layout Randomization (ASLR), stack canaries, or non-executable stack protections that are common in desktop operating systems.

Attack Vector

The attack can be executed remotely over the network. An unauthenticated attacker can craft a malicious HTTP request to the router's web interface, providing an oversized value for the entrys parameter when invoking the fromAddressNat function. The overflow corrupts the stack memory, potentially allowing the attacker to redirect execution flow to attacker-controlled code.

The exploitation process typically involves:

1. Identifying the vulnerable endpoint on the router's web interface
2. Crafting a malicious request with an oversized entrys parameter
3. Overwriting the return address to redirect execution
4. Executing arbitrary shellcode or return-oriented programming (ROP) chains

Technical details of this vulnerability are documented in the GitHub Vulnerability Documentation.

Detection Methods for CVE-2024-30589

Indicators of Compromise

• Unexpected router reboots or crashes indicating exploitation attempts
• Unusual outbound network connections from the router to unknown external hosts
• Modified router configuration or firmware settings
• Presence of unauthorized administrative accounts on the device
• Network traffic anomalies showing large or malformed HTTP requests to the router's web interface

Detection Strategies

• Monitor network traffic for unusually large HTTP POST requests targeting the router's web management interface
• Implement intrusion detection rules to identify buffer overflow attack patterns in HTTP parameters
• Deploy network segmentation to isolate IoT devices and monitor cross-segment traffic
• Use firmware integrity verification tools to detect unauthorized modifications

Monitoring Recommendations

• Enable logging on the router if available and forward logs to a central SIEM for analysis
• Implement network-level monitoring for traffic anomalies to and from the router's management interface
• Establish baseline behavior for the router and alert on deviations such as unexpected process spawning or memory usage spikes

How to Mitigate CVE-2024-30589

Immediate Actions Required

• Restrict access to the router's web management interface to trusted internal networks only
• Disable remote management features if not required
• Place the router behind a firewall and block external access to management ports
• Monitor for firmware updates from Tenda and apply patches when available
• Consider replacing end-of-life devices with supported alternatives

Patch Information

At the time of this analysis, no vendor patch information is available in the CVE data. Organizations should monitor Tenda's official support channels for security updates addressing this vulnerability. The affected firmware version is 1.2.0.14(408) - check for newer firmware releases that may include fixes for this stack overflow issue.

Workarounds

• Disable the web-based management interface entirely if not needed for operations
• Implement network access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
• Deploy a VPN solution for remote management instead of exposing the router's web interface directly
• Use a network-level firewall or IPS to filter malicious requests targeting known vulnerable endpoints

# Network segmentation example using iptables
# Block external access to router management interface
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP

# Only allow management from specific trusted host
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP