CVE-2025-6897: D-Link DI-7300G+ Firmware RCE Vulnerability

CVE-2025-6897 Overview

A critical OS command injection vulnerability has been identified in the D-Link DI-7300G+ router firmware version 19.12.25A1. This vulnerability exists within the httpd_debug.asp file, where improper handling of the Time argument allows an authenticated attacker on the adjacent network to inject and execute arbitrary operating system commands. The exploit for this vulnerability has been publicly disclosed, increasing the risk of active exploitation attempts.

Critical Impact

Attackers with adjacent network access and low-level privileges can execute arbitrary OS commands on the affected D-Link router, potentially leading to complete device compromise, network traffic interception, and lateral movement within the network.

Affected Products

• D-Link DI-7300G+ Firmware version 19.12.25A1
• D-Link DI-7300G+ Hardware

Discovery Timeline

• 2025-06-30 - CVE-2025-6897 published to NVD
• 2025-07-01 - Last updated in NVD database

Technical Details for CVE-2025-6897

Vulnerability Analysis

This vulnerability is classified as an OS Command Injection (CWE-78) and Command Injection (CWE-77) flaw in the D-Link DI-7300G+ router's web management interface. The vulnerable component resides in the httpd_debug.asp file, which fails to properly sanitize user-supplied input in the Time parameter before passing it to an operating system shell for execution.

The attack requires adjacent network access, meaning the attacker must be on the same local network segment as the vulnerable device. While low-level authentication is required, this barrier is often easily overcome through default credentials or credential reuse common in router deployments. The vulnerability affects confidentiality, integrity, and availability of the device, though the impact is contained to the vulnerable system without extending to other connected components.

Root Cause

The root cause of this vulnerability is insufficient input validation and sanitization in the httpd_debug.asp script. When processing the Time argument, the application directly incorporates user-controlled data into shell commands without properly escaping or filtering special characters and command delimiters. This allows attackers to break out of the intended command context and inject arbitrary shell commands that execute with the privileges of the web server process.

Attack Vector

The attack is executed over the adjacent network, requiring the attacker to have local network access to the vulnerable D-Link router. An authenticated user can craft a malicious HTTP request to the httpd_debug.asp endpoint with a specially crafted Time parameter containing OS command injection payloads. Common injection techniques include using shell metacharacters such as semicolons (;), pipes (|), or command substitution syntax ($() or backticks) to append malicious commands to the legitimate time-setting operation.

The vulnerability mechanism involves manipulating the Time parameter in requests to httpd_debug.asp. When the router processes this input without proper sanitization, injected shell commands are executed in the context of the router's operating system. Attackers typically leverage such vulnerabilities to establish reverse shells, modify device configurations, intercept network traffic, or use the compromised device as a pivot point for further network intrusion. Technical details are available in the GitHub D-Link CVE Document.

Detection Methods for CVE-2025-6897

Indicators of Compromise

• Unusual HTTP requests to /httpd_debug.asp containing shell metacharacters (;, |, $(), backticks) in the Time parameter
• Unexpected outbound connections from the router to external IP addresses
• Unauthorized changes to router configuration files or firmware
• Presence of unfamiliar processes running on the router when accessed via console

Detection Strategies

• Monitor HTTP traffic to the router's web interface for requests containing command injection patterns in parameter values
• Implement network-based intrusion detection signatures that alert on httpd_debug.asp access with suspicious payloads
• Regularly review router logs for authentication attempts and access to debugging endpoints
• Deploy SentinelOne Singularity for network visibility to detect anomalous traffic patterns from IoT devices

Monitoring Recommendations

• Enable verbose logging on the D-Link router if available and forward logs to a centralized SIEM solution
• Monitor for lateral movement attempts originating from the router's network segment
• Implement network segmentation to isolate IoT devices and routers from critical infrastructure
• Conduct periodic vulnerability scans of network infrastructure devices

How to Mitigate CVE-2025-6897

Immediate Actions Required

• Restrict access to the router's web management interface to trusted administrators only via network ACLs or firewall rules
• Disable remote management access and limit administration to physically connected devices
• Change default credentials to strong, unique passwords for all router accounts
• Monitor for and apply any firmware updates released by D-Link addressing this vulnerability

Patch Information

As of the last update on 2025-07-01, no official patch has been released by D-Link for this vulnerability. Organizations should monitor the D-Link Official Website for security advisories and firmware updates. Additionally, vulnerability tracking information is available through VulDB #314389.

Workarounds

• Implement strict network access controls to limit which devices can reach the router's administrative interface
• Disable the httpd_debug.asp endpoint if not required for normal operations (may require custom firmware modifications)
• Place the affected router behind a more secure firewall or replace with a non-vulnerable device
• Consider deploying a Web Application Firewall (WAF) on the network segment to filter malicious requests

# Example: Restrict access to router management interface via iptables on upstream device
# Block external access to router management ports
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow only specific management workstation
iptables -I FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT