CVE-2024-10914: D-Link DNS-320 Firmware RCE Vulnerability

CVE-2024-10914 Overview

CVE-2024-10914 is a critical command injection vulnerability affecting multiple D-Link Network Attached Storage (NAS) devices, including the DNS-320, DNS-320LW, DNS-325, and DNS-340L models. The vulnerability exists in the cgi_user_add function within the /cgi-bin/account_mgr.cgi endpoint, where improper handling of the name parameter allows attackers to inject and execute arbitrary operating system commands remotely. This vulnerability has been publicly disclosed and exploit information is available, significantly increasing the risk to unpatched devices.

Critical Impact

Remote attackers can achieve full system compromise on affected D-Link NAS devices through command injection, potentially leading to data theft, ransomware deployment, or use of the device as a pivot point for further network attacks.

Affected Products

• D-Link DNS-320 and DNS-320 Firmware
• D-Link DNS-320LW and DNS-320LW Firmware
• D-Link DNS-325 and DNS-325 Firmware
• D-Link DNS-340L and DNS-340L Firmware

Discovery Timeline

• November 6, 2024 - CVE-2024-10914 published to NVD
• November 24, 2024 - Last updated in NVD database

Technical Details for CVE-2024-10914

Vulnerability Analysis

This command injection vulnerability affects the user account management functionality of D-Link NAS devices. The vulnerable endpoint /cgi-bin/account_mgr.cgi accepts user-supplied input through the name parameter when the cmd=cgi_user_add action is invoked. The input is not properly sanitized before being passed to system-level functions, allowing an attacker to inject malicious commands that execute with the privileges of the web server process.

The attack can be launched remotely over the network, though the complexity is noted as being somewhat higher than typical injection attacks. This may be due to factors such as authentication requirements, specific payload formatting needs, or timing considerations. Despite the elevated complexity, the publicly available exploit information makes this vulnerability particularly dangerous.

According to Bleeping Computer's security report, D-Link has indicated they will not be releasing patches for these affected devices as they have reached end-of-life status, leaving approximately 60,000 devices permanently vulnerable.

Root Cause

The root cause of CVE-2024-10914 is improper input validation (CWE-74 - Injection). The cgi_user_add function fails to adequately sanitize the name parameter before incorporating it into system commands. This allows attackers to break out of the intended command context and execute arbitrary commands by injecting shell metacharacters or command separators.

Attack Vector

The attack is network-based and targets the web management interface of affected D-Link NAS devices. An attacker would craft a malicious HTTP request to the /cgi-bin/account_mgr.cgi endpoint with a specially crafted name parameter containing OS command injection payloads. Upon processing this request, the vulnerable CGI script executes the injected commands in the context of the device's operating system.

The exploitation involves sending a crafted request to the account_mgr.cgi script with the cgi_user_add command. By manipulating the name parameter with shell metacharacters and additional commands, an attacker can achieve arbitrary command execution. Detailed technical analysis is available in the Netsecfish Command Injection Analysis.

Detection Methods for CVE-2024-10914

Indicators of Compromise

• Unusual HTTP requests to /cgi-bin/account_mgr.cgi containing shell metacharacters (;, |, $(), backticks) in the name parameter
• Unexpected processes spawned by the web server process on NAS devices
• Unauthorized outbound network connections from NAS devices to unknown external IP addresses
• Suspicious file modifications or new files created in system directories on the NAS

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing command injection patterns targeting /cgi-bin/account_mgr.cgi
• Monitor network traffic for HTTP requests to D-Link NAS devices that contain suspicious parameter values with shell metacharacters
• Deploy network intrusion detection system (NIDS) signatures specifically targeting CVE-2024-10914 exploitation attempts
• Review web server access logs on D-Link NAS devices for anomalous requests to the account management CGI scripts

Monitoring Recommendations

• Enable verbose logging on D-Link NAS devices and forward logs to a centralized SIEM for analysis
• Establish baseline network behavior for NAS devices and alert on deviations such as unexpected outbound connections
• Monitor for any changes to user accounts on the NAS devices that were not initiated through legitimate administrative actions
• Implement file integrity monitoring on critical system directories of the NAS devices where possible

How to Mitigate CVE-2024-10914

Immediate Actions Required

• Isolate affected D-Link NAS devices from direct internet exposure by placing them behind a firewall or removing port forwarding rules
• Disable remote management interfaces if not absolutely necessary for operations
• Implement strict network segmentation to limit the blast radius if a device is compromised
• Begin planning for device replacement as D-Link has stated these end-of-life devices will not receive security patches

Patch Information

According to reports from Bleeping Computer, D-Link has confirmed that the affected devices (DNS-320, DNS-320LW, DNS-325, and DNS-340L) have reached end-of-life status and will not receive security patches for this vulnerability. D-Link recommends that customers retire these products and replace them with supported alternatives. For more information, visit the D-Link Official Website.

Workarounds

• Block external access to the NAS web management interface at the network perimeter firewall
• Use a VPN for remote access to the NAS instead of exposing the management interface directly to the internet
• Implement IP whitelisting at the network level to restrict access to the NAS management interface to trusted IP addresses only
• Consider deploying a reverse proxy with WAF capabilities in front of the NAS to filter malicious requests

# Example: Block external access to NAS on router/firewall
# Deny inbound connections to NAS management port from WAN
iptables -A INPUT -p tcp --dport 80 -i eth0 -s 0.0.0.0/0 -j DROP
iptables -A INPUT -p tcp --dport 443 -i eth0 -s 0.0.0.0/0 -j DROP

# Allow only internal network access
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT