CVE-2025-4454: D-Link DIR-619L Firmware RCE Vulnerability

CVE-2025-4454 Overview

A command injection vulnerability has been identified in the D-Link DIR-619L wireless router firmware version 2.04B04. This vulnerability exists within the wake_on_lan function, where improper handling of the mac parameter allows an attacker to inject arbitrary operating system commands. The vulnerability can be exploited remotely by an authenticated attacker, potentially leading to complete device compromise.

Critical Impact

This end-of-life router is vulnerable to remote command injection through the wake_on_lan function, allowing attackers to execute arbitrary commands on the underlying operating system with no patch available from the vendor.

Affected Products

• D-Link DIR-619L Firmware version 2.04B04
• D-Link DIR-619L Hardware (all revisions running affected firmware)

Discovery Timeline

• 2025-05-09 - CVE-2025-4454 published to NVD
• 2025-05-13 - Last updated in NVD database

Technical Details for CVE-2025-4454

Vulnerability Analysis

This command injection vulnerability (CWE-77) stems from insufficient input validation in the wake_on_lan function of the D-Link DIR-619L router firmware. The mac parameter, which is intended to accept MAC address values for Wake-on-LAN functionality, does not properly sanitize user-supplied input before passing it to system commands.

The vulnerability is classified under both CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component) and CWE-77 (Improper Neutralization of Special Elements used in a Command). An attacker with network access and valid credentials can exploit this flaw to execute arbitrary operating system commands on the router, potentially gaining full control over the device.

The attack vector is network-based, requiring low privileges (authenticated access) but no user interaction. Successful exploitation could allow an attacker to modify router configurations, intercept network traffic, pivot to internal network resources, or use the compromised device as part of a botnet.

Root Cause

The root cause of this vulnerability is the lack of proper input sanitization in the wake_on_lan function. The mac parameter value is directly incorporated into a system command without adequate validation or escaping of shell metacharacters. This allows specially crafted input containing command separators or shell operators to break out of the intended command context and execute arbitrary commands.

Attack Vector

The attack can be initiated remotely over the network by any authenticated user who has access to the router's administrative interface. The attacker crafts a malicious request to the wake_on_lan function with a specially crafted mac parameter value containing shell command injection payloads. Common injection techniques include using shell metacharacters such as semicolons (;), pipes (|), backticks, or $(command) syntax to append or inject additional commands.

For detailed technical analysis and proof-of-concept information, refer to the GitHub PoC Repository and VulDB Entry #308068.

Detection Methods for CVE-2025-4454

Indicators of Compromise

• Unusual outbound network connections from the router to unknown external IP addresses
• Unexpected changes to router configuration files or startup scripts
• Suspicious HTTP requests to the router's web interface containing shell metacharacters in the mac parameter
• Unexplained CPU or memory utilization spikes on the affected device
• Presence of unauthorized user accounts or SSH keys on the router

Detection Strategies

• Monitor HTTP traffic to the router's administrative interface for requests containing the wake_on_lan function with suspicious mac parameter values
• Implement network-based intrusion detection rules to identify command injection patterns in router management traffic
• Review router access logs for unusual authentication patterns or repeated access to Wake-on-LAN functionality
• Deploy endpoint detection solutions capable of monitoring network device behavior for anomalous activity

Monitoring Recommendations

• Enable verbose logging on the D-Link DIR-619L if supported, capturing all administrative interface access
• Implement network segmentation to restrict access to router management interfaces from untrusted networks
• Monitor for DNS queries or network connections indicative of botnet command-and-control communication
• Regularly audit devices on the network for firmware versions known to be vulnerable

How to Mitigate CVE-2025-4454

Immediate Actions Required

• Restrict access to the router's administrative interface to trusted IP addresses only using firewall rules
• Disable remote management capabilities if not required for business operations
• Change default and weak administrative credentials to strong, unique passwords
• Consider replacing the end-of-life D-Link DIR-619L with a currently supported router model
• Implement network segmentation to isolate the vulnerable device from critical network resources

Patch Information

The D-Link DIR-619L has reached end-of-life status and is no longer supported by the vendor. No security patch is available for this vulnerability. D-Link has been notified of this disclosure, but users should not expect a firmware update to address this issue.

Organizations using this device are strongly advised to migrate to a supported router model that receives regular security updates. For vendor information, visit the D-Link Official Website.

Workarounds

• Disable the Wake-on-LAN feature entirely if not required for operations
• Implement strict network access control lists (ACLs) to limit which hosts can communicate with the router's management interface
• Place the router behind an additional firewall that can filter and inspect HTTP requests to the device
• Use VPN access for any remote administration needs, avoiding direct exposure of the management interface to untrusted networks
• Monitor network traffic for exploitation attempts while planning device replacement

# Example: Restrict router management access using iptables on upstream firewall
# Block external access to router management interface (adjust IPs as needed)
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 80 -s ! 192.168.0.0/24 -j DROP
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 443 -s ! 192.168.0.0/24 -j DROP

# Allow only specific admin workstation
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 80 -s 192.168.0.100 -j ACCEPT
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 443 -s 192.168.0.100 -j ACCEPT