CVE-2024-2854 Overview
A critical OS command injection vulnerability has been discovered in the Tenda AC18 router firmware version 15.03.05.05. The vulnerability exists in the formSetSambaConf function located at /goform/setsambacfg, where improper handling of the usbName parameter allows remote attackers to inject and execute arbitrary operating system commands on the affected device.
Critical Impact
This vulnerability enables unauthenticated remote attackers to execute arbitrary commands on the router with root privileges, potentially leading to complete device compromise, network infiltration, and persistent access to connected networks.
Affected Products
- Tenda AC18 Firmware version 15.03.05.05
- Tenda AC18 Router Hardware
Discovery Timeline
- 2024-03-24 - CVE-2024-2854 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2024-2854
Vulnerability Analysis
This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The affected function formSetSambaConf processes user-supplied input from the usbName parameter without adequate sanitization or validation before passing it to system-level commands.
The exploitation can be performed remotely over the network without requiring authentication or user interaction, making this a particularly dangerous vulnerability for consumer and small business routers. Successful exploitation grants attackers the ability to execute arbitrary commands with the privileges of the router's operating system, typically root-level access on embedded Linux-based firmware.
The vendor, Tenda, was contacted about this vulnerability prior to public disclosure but did not respond.
Root Cause
The root cause of this vulnerability lies in insufficient input validation within the formSetSambaConf function. The usbName parameter accepts user-controlled input that is directly incorporated into system commands without proper sanitization. This allows attackers to break out of the intended command context by injecting shell metacharacters such as semicolons, pipes, backticks, or command substitution sequences.
The affected endpoint /goform/setsambacfg is part of the router's Samba (SMB) configuration functionality, which is accessible through the device's web management interface. The lack of input filtering enables command chaining and arbitrary command execution.
Attack Vector
The attack can be launched remotely over the network by sending specially crafted HTTP requests to the vulnerable endpoint. An attacker constructs a malicious request to /goform/setsambacfg with a payload injected into the usbName parameter.
For example, an attacker could append command injection sequences to the parameter value, causing the router to execute unintended system commands. The exploit has been publicly disclosed, increasing the risk of widespread exploitation against unpatched devices.
Technical details and analysis of this vulnerability are documented in the GitHub IoT Vulnerability Documentation.
Detection Methods for CVE-2024-2854
Indicators of Compromise
- Unusual outbound network connections from the router to unknown external IP addresses
- Unexpected changes to router configuration or DNS settings
- Presence of unknown processes or services running on the device
- Suspicious HTTP POST requests to /goform/setsambacfg in router logs
- Signs of persistent access mechanisms such as unauthorized SSH keys or cron jobs
Detection Strategies
- Monitor network traffic for anomalous HTTP requests targeting /goform/setsambacfg endpoints
- Implement intrusion detection rules to identify command injection patterns in web requests (semicolons, pipes, backticks, $() sequences)
- Deploy network-level monitoring to detect unexpected communications from IoT devices
- Review router access logs for repeated requests to the vulnerable endpoint
Monitoring Recommendations
- Enable logging on the router if supported and forward logs to a centralized SIEM
- Monitor for firmware modifications or unexpected configuration changes
- Implement network segmentation to isolate IoT devices from critical infrastructure
- Use SentinelOne Singularity to monitor network behavior and detect anomalous activity from compromised devices
How to Mitigate CVE-2024-2854
Immediate Actions Required
- Isolate affected Tenda AC18 routers from untrusted networks until a patch is available
- Disable remote management features and restrict access to the web administration interface
- Place the router behind a firewall and limit access to trusted IP addresses only
- Consider replacing the affected device with a router from a vendor with active security support
- Monitor network traffic for signs of exploitation
Patch Information
No official patch has been released by Tenda at this time. The vendor was contacted about this vulnerability but did not respond. Users should monitor Tenda's official website and the VulDB entry for any future security updates.
Given the lack of vendor response, organizations should evaluate alternative mitigation strategies or device replacement.
Workarounds
- Disable the Samba/USB sharing functionality on the router if not required
- Restrict access to the router's web management interface to trusted internal networks only
- Implement network-level access controls to block external access to the router's administration ports
- Consider deploying a network firewall or UTM device in front of the affected router to filter malicious requests
# Example: Block external access to router management interface using iptables on upstream firewall
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
