CVE-2024-35580: Tenda AX1806 Buffer Overflow Vulnerability

CVE-2024-35580 Overview

CVE-2024-35580 is a stack overflow vulnerability affecting Tenda AX1806 wireless routers running firmware version 1.0.0.1. The vulnerability exists in the formSetIptv function, which fails to properly validate the length of user-supplied input passed through the adv.iptv.stbpvid parameter. This memory corruption flaw can be exploited remotely without authentication, potentially allowing attackers to execute arbitrary code or cause a denial of service condition on affected devices.

Critical Impact

This vulnerability enables remote unauthenticated attackers to trigger a stack-based buffer overflow on Tenda AX1806 routers, potentially leading to complete device compromise, arbitrary code execution, or denial of service.

Affected Products

• Tenda AX1806 Firmware version 1.0.0.1
• Tenda AX1806 Hardware

Discovery Timeline

• 2024-05-20 - CVE-2024-35580 published to NVD
• 2025-03-17 - Last updated in NVD database

Technical Details for CVE-2024-35580

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a critical memory corruption issue that occurs when the formSetIptv function processes user input without adequate bounds checking. The function handles IPTV configuration parameters, including the adv.iptv.stbpvid parameter, which is vulnerable to overflow attacks.

When an attacker sends a specially crafted HTTP request containing an excessively long value for the adv.iptv.stbpvid parameter, the data overflows the allocated stack buffer. This overflow can corrupt adjacent memory on the stack, including return addresses and saved registers. The network-accessible nature of this vulnerability, combined with the lack of authentication requirements, makes it particularly dangerous for internet-exposed or LAN-accessible routers.

Root Cause

The root cause of this vulnerability is insufficient input validation in the formSetIptv function within the Tenda AX1806 firmware. The function fails to verify that the length of the adv.iptv.stbpvid parameter does not exceed the size of the destination buffer before copying the data. This lack of boundary checking allows user-controlled data to overflow the stack buffer, enabling potential code execution or system crashes.

Attack Vector

The attack vector for CVE-2024-35580 is network-based and requires no authentication or user interaction. An attacker with network access to the router's management interface can exploit this vulnerability by sending a malicious HTTP request to the affected endpoint. The request would contain an oversized value for the adv.iptv.stbpvid parameter, triggering the stack overflow condition.

The exploitation process involves:

1. Identifying a Tenda AX1806 router running vulnerable firmware version 1.0.0.1
2. Crafting an HTTP request targeting the IPTV configuration form handler
3. Including an excessively long adv.iptv.stbpvid parameter value designed to overflow the stack buffer
4. Sending the malicious request to the router's web management interface

Technical details and analysis are available in the Notion Security Analysis.

Detection Methods for CVE-2024-35580

Indicators of Compromise

• Unexpected router reboots or crashes, particularly when processing web management requests
• Anomalous HTTP POST requests to IPTV configuration endpoints containing unusually long parameter values
• Network traffic patterns indicating repeated requests to the formSetIptv handler
• Router configuration changes that were not authorized by administrators

Detection Strategies

• Monitor web management interface traffic for HTTP requests with abnormally long parameter values targeting IPTV configuration endpoints
• Implement network intrusion detection rules to identify patterns consistent with buffer overflow exploitation attempts against Tenda devices
• Deploy deep packet inspection to analyze HTTP POST body content for oversized adv.iptv.stbpvid parameters
• Review router logs for evidence of service crashes or unexpected restarts

Monitoring Recommendations

• Segment IoT and network infrastructure devices on separate VLANs with strict access controls
• Enable logging on network firewalls and analyze traffic patterns to and from router management interfaces
• Monitor for firmware version information during network scans to identify vulnerable Tenda AX1806 devices
• Implement alerting for any direct internet access attempts to router management interfaces

How to Mitigate CVE-2024-35580

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management if not required, limiting access to the local network
• Implement network segmentation to isolate vulnerable routers from untrusted networks
• Monitor Tenda's support channels for firmware updates addressing this vulnerability

Patch Information

At the time of publication, no official patch from Tenda has been identified in the available CVE data. Organizations should monitor the Tenda support website for firmware updates and apply patches as soon as they become available. Contact Tenda support directly for information about remediation options.

Workarounds

• Disable remote management access to prevent internet-based exploitation
• Configure firewall rules to block external access to the router's web management interface (typically TCP port 80 or 443)
• Implement a VPN solution for remote administration needs instead of exposing the management interface directly
• Consider replacing the affected device with a model that receives regular security updates if no patch is forthcoming

# Example firewall rule to restrict management interface access (implement on upstream firewall)
# Block external access to Tenda router management interface
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -d <ROUTER_IP> -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -d <ROUTER_IP> -j DROP