CVE-2025-4350: D-Link DIR-600L Firmware RCE Vulnerability

CVE-2025-4350 Overview

A critical command injection vulnerability has been discovered in D-Link DIR-600L wireless routers running firmware versions up to 2.07B01. This vulnerability affects the wake_on_lan function, where improper handling of the host argument allows remote attackers to inject and execute arbitrary system commands. The vulnerability is particularly concerning because the affected products have reached end-of-life status and are no longer supported by D-Link, meaning no official patches will be released.

Critical Impact

Remote attackers with network access can achieve complete system compromise on affected D-Link DIR-600L routers by exploiting command injection in the Wake-on-LAN functionality, potentially gaining full control over the device and network traffic.

Affected Products

• D-Link DIR-600L Firmware (versions up to 2.07B01)
• D-Link DIR-600L Hardware Device
• All variants of D-Link DIR-600L running vulnerable firmware

Discovery Timeline

• 2025-05-06 - CVE-2025-4350 published to NVD
• 2025-05-12 - Last updated in NVD database

Technical Details for CVE-2025-4350

Vulnerability Analysis

This command injection vulnerability (CWE-77) exists within the wake_on_lan function of the D-Link DIR-600L router firmware. The root cause is improper neutralization of special elements used in a command, classified under CWE-74 (Injection). When processing Wake-on-LAN requests, the router firmware fails to properly sanitize the host parameter before incorporating it into system commands executed on the device.

The vulnerability can be exploited remotely over the network by authenticated users with low privileges. No user interaction is required for successful exploitation. Upon successful attack, an adversary can achieve high impact on confidentiality, integrity, and availability of the affected system—effectively gaining complete control over the router.

Root Cause

The vulnerability stems from improper input validation in the wake_on_lan function. The host argument is passed directly to system command execution without adequate sanitization or escaping of shell metacharacters. This allows specially crafted input containing command separators (such as ;, |, &&, or backticks) to break out of the intended command context and execute arbitrary commands with the privileges of the router's web service process.

Attack Vector

The attack is network-based, requiring the attacker to have network connectivity to the vulnerable router's management interface. The exploitation flow involves:

1. An attacker sends a malicious request to the Wake-on-LAN functionality
2. The host parameter contains embedded shell commands using command injection techniques
3. The router's firmware passes the unsanitized input to a system shell
4. The injected commands execute with the privileges of the router's web server process
5. The attacker achieves arbitrary command execution on the embedded Linux system

Since router firmware typically runs with elevated privileges, successful exploitation often results in complete device compromise, allowing attackers to intercept network traffic, modify DNS settings, pivot to internal networks, or incorporate the device into a botnet.

For technical details and proof-of-concept information, refer to the GitHub PoC Repository and VulDB Entry #307468.

Detection Methods for CVE-2025-4350

Indicators of Compromise

• Unusual outbound connections from the router to unknown IP addresses or command-and-control servers
• Unexpected modifications to router configuration, DNS settings, or firewall rules
• Anomalous network traffic patterns originating from the router's management interface
• Evidence of shell command execution in router logs referencing the wake_on_lan function

Detection Strategies

• Monitor network traffic for suspicious HTTP requests targeting Wake-on-LAN endpoints containing shell metacharacters (;, |, &&, `, $())
• Implement network intrusion detection rules to identify command injection patterns in traffic destined for D-Link router management interfaces
• Review router access logs for authentication attempts followed by requests to WOL functionality with malformed parameters
• Deploy network segmentation to isolate vulnerable legacy devices and monitor cross-segment traffic

Monitoring Recommendations

• Isolate D-Link DIR-600L devices on a separate network segment with restricted access and enhanced logging
• Configure alerts for any management interface access from untrusted networks
• Monitor for DNS resolution changes or unexpected outbound connections from the router
• Implement periodic firmware integrity checks where possible to detect unauthorized modifications

How to Mitigate CVE-2025-4350

Immediate Actions Required

• Replace affected D-Link DIR-600L routers with supported devices as this product has reached end-of-life with no patches forthcoming
• Disable remote management access to the router's web interface immediately
• Restrict access to the router's management interface to trusted internal hosts only using firewall rules
• Disable the Wake-on-LAN functionality if it is not required for network operations

Patch Information

D-Link has discontinued support for the DIR-600L router series, and no official security patch will be released for this vulnerability. The only permanent mitigation is device replacement with a currently supported router model. For reference, consult the D-Link Official Website for information on supported replacement products.

Workarounds

• Implement strict network access controls to limit management interface access to trusted administrator IP addresses only
• Place the vulnerable router behind a firewall that filters and inspects traffic to the management interface
• Disable Wake-on-LAN functionality entirely through the router's configuration interface
• Consider deploying a third-party firewall or security appliance to filter malicious requests before they reach the vulnerable device
• Segment the network to minimize the blast radius if the device is compromised

# Example firewall rule to restrict management access (iptables)
# Block external access to router management port (typically 80/443)
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 443 -j DROP
# Allow only trusted admin hosts
iptables -I FORWARD -s <TRUSTED_ADMIN_IP> -d <ROUTER_IP> -p tcp --dport 80 -j ACCEPT