CVE-2024-28354: Trendnet TEW-827DRU RCE Vulnerability

CVE-2024-28354 Overview

A critical command injection vulnerability exists in the TRENDnet TEW-827DRU router with firmware version 2.10B01. This vulnerability allows remote attackers to inject arbitrary commands through the usapps.@smb[%d].username parameter in the apply.cgi interface, enabling complete device compromise with root shell privileges.

Critical Impact

Successful exploitation grants attackers root-level access to the router, allowing complete control over network traffic, device configuration, and potential pivoting to internal network resources.

Affected Products

• TRENDnet TEW-827DRU Router
• TRENDnet TEW-827DRU Firmware version 2.10B01

Discovery Timeline

• 2024-03-15 - CVE-2024-28354 published to NVD
• 2025-04-01 - Last updated in NVD database

Technical Details for CVE-2024-28354

Vulnerability Analysis

This command injection vulnerability (CWE-77) affects the web management interface of the TRENDnet TEW-827DRU router. The vulnerability stems from insufficient input validation in the apply.cgi interface, specifically when processing the usapps.@smb[%d].username parameter. When malicious input is submitted through POST requests to this endpoint, the router fails to properly sanitize user-supplied data before passing it to system shell commands, resulting in arbitrary command execution.

The network-accessible nature of this vulnerability means attackers can exploit it remotely without authentication, making it particularly dangerous for internet-facing routers or those on compromised networks. Successful exploitation results in immediate root shell access, giving attackers complete control over the device.

Root Cause

The root cause is improper neutralization of special elements used in a command (CWE-77). The apply.cgi interface processes the SMB username configuration parameter without adequate input sanitization. When the usapps.@smb[%d].username parameter contains shell metacharacters or command substitution sequences, these are interpreted and executed by the underlying system shell with root privileges rather than being treated as literal string values.

Attack Vector

The attack vector is network-based, requiring an attacker to send specially crafted HTTP POST requests to the router's web management interface. The attacker targets the apply.cgi endpoint and injects malicious commands through the vulnerable usapps.@smb[%d].username parameter. Since the commands execute with root privileges, the attacker gains full control of the device immediately upon successful exploitation.

The vulnerability can be exploited by crafting a POST request to the apply.cgi interface with command injection payloads embedded in the username parameter. Common techniques include using command separators such as semicolons, pipes, or backticks to append arbitrary commands that will be executed by the router's operating system. For detailed technical information, refer to the Notion Security Document.

Detection Methods for CVE-2024-28354

Indicators of Compromise

• Unexpected outbound network connections from the router to unknown IP addresses
• Unusual processes running on the router that are not part of normal firmware operations
• Modified router configuration or new administrative accounts created without authorization
• Network traffic anomalies suggesting command and control (C2) communication from the router

Detection Strategies

• Monitor HTTP POST requests to apply.cgi containing suspicious characters (;, |, `, $()) in the usapps.@smb parameters
• Implement network intrusion detection rules to identify command injection patterns targeting the TEW-827DRU web interface
• Review router logs for unusual administrative access attempts or configuration changes
• Deploy network monitoring to detect anomalous traffic patterns originating from the router

Monitoring Recommendations

• Enable logging on the router's web management interface if supported by the firmware
• Implement network-level monitoring for traffic to and from the router management ports (typically TCP 80/443)
• Use network behavior analysis tools to baseline normal router activity and alert on deviations
• Regularly audit router configurations for unauthorized changes

How to Mitigate CVE-2024-28354

Immediate Actions Required

• Disable remote management access to the router's web interface from the WAN side immediately
• Restrict access to the router's administrative interface to trusted internal IP addresses only
• Place the router behind a firewall that blocks external access to management ports
• Monitor for any signs of compromise and consider replacing the device if suspicious activity is detected

Patch Information

As of the last update on 2025-04-01, no official patch information has been published by TRENDnet for this vulnerability. Users should check the TRENDnet support website regularly for firmware updates and security advisories. Given the critical nature of this vulnerability and the lack of available patches, organizations should consider replacing affected devices with alternatives that have active security support.

Workarounds

• Disable the web management interface entirely if not required for router administration
• Configure firewall rules to allow management access only from specific trusted IP addresses on the internal network
• If remote management is necessary, use a VPN to access the internal network rather than exposing the router interface directly
• Consider network segmentation to limit the potential impact if the router is compromised
• Replace the TEW-827DRU with a router that receives active security updates

# Example firewall rule to restrict management access (adjust for your environment)
# Block external access to router management interface
iptables -A INPUT -i wan0 -p tcp --dport 80 -j DROP
iptables -A INPUT -i wan0 -p tcp --dport 443 -j DROP

# Allow management only from trusted internal subnet
iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 80 -j ACCEPT