CVE-2025-11408: D-Link DI-7001 Buffer Overflow Vulnerability

CVE-2025-11408 Overview

A buffer overflow vulnerability has been identified in the D-Link DI-7001 MINI router firmware version 24.04.18B1. The vulnerability exists within an unknown function of the /dbsrv.asp file, where improper handling of the str argument allows an attacker to trigger a buffer overflow condition. This vulnerability can be exploited remotely by authenticated attackers, potentially leading to arbitrary code execution, system compromise, or denial of service on affected devices.

Critical Impact

Remote attackers with low privileges can exploit this buffer overflow vulnerability in D-Link DI-7001 MINI routers to potentially gain complete control over the affected device, compromising network security and enabling further attacks on connected systems.

Affected Products

• D-Link DI-7001MINI-8G Firmware version 24.04.18B1
• D-Link DI-7001MINI-8G Hardware revision B1

Discovery Timeline

• 2025-10-07 - CVE-2025-11408 published to NVD
• 2025-11-19 - Last updated in NVD database

Technical Details for CVE-2025-11408

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the /dbsrv.asp endpoint of the D-Link DI-7001 MINI router's web management interface. When processing the str argument, the application fails to properly validate input boundaries before copying data into a fixed-size buffer. This oversight enables attackers to supply specially crafted input that exceeds the allocated buffer size, corrupting adjacent memory regions.

The vulnerability is exploitable over the network, requiring only low-privilege authentication. The attack does not require user interaction, making it particularly dangerous in environments where the router's management interface is exposed. The exploit has been publicly disclosed through a GitHub Issue Discussion, increasing the risk of active exploitation.

Root Cause

The root cause of this vulnerability stems from insufficient input validation and improper bounds checking in the /dbsrv.asp handler. The affected function processes user-supplied data through the str parameter without verifying that the input length does not exceed the destination buffer's capacity. This is a classic buffer overflow pattern commonly found in embedded device firmware where memory-safe programming practices are not consistently applied.

The firmware developers failed to implement proper length checks or use safer string handling functions that prevent buffer overruns. In embedded systems like routers, such vulnerabilities are particularly severe because they often run with elevated privileges and lack modern memory protection mechanisms like ASLR or stack canaries.

Attack Vector

The attack is conducted remotely over the network against the router's web management interface. An attacker must have low-privilege access to the device to exploit this vulnerability. The attack flow involves:

1. Authenticating to the D-Link DI-7001 MINI web interface with valid credentials (even low-privilege accounts)
2. Sending a malicious HTTP request to the /dbsrv.asp endpoint
3. Crafting the str parameter with oversized or specially structured input designed to overflow the buffer
4. Achieving arbitrary code execution or causing a denial of service condition

The vulnerability allows attackers to potentially achieve high impact on confidentiality, integrity, and availability of the affected device. Successful exploitation could enable complete compromise of the router, traffic interception, network pivoting, or persistent backdoor installation.

Detection Methods for CVE-2025-11408

Indicators of Compromise

• Unusual HTTP POST or GET requests targeting /dbsrv.asp with abnormally long str parameter values
• Unexpected router reboots or service crashes that may indicate exploitation attempts
• Unexplained changes to router configuration or firmware
• Suspicious outbound connections from the router to unknown IP addresses
• Evidence of unauthorized access in router authentication logs

Detection Strategies

• Deploy network-based intrusion detection systems (IDS) with rules to identify malformed HTTP requests to /dbsrv.asp endpoints
• Monitor web server logs on D-Link devices for requests containing unusually long parameter values
• Implement anomaly detection for buffer overflow attack patterns against IoT and network devices
• Configure SentinelOne Singularity to monitor network traffic for exploitation attempts against D-Link infrastructure

Monitoring Recommendations

• Enable detailed logging on D-Link router management interfaces and forward logs to a centralized SIEM
• Set up alerts for authentication attempts followed by requests to /dbsrv.asp
• Monitor network segmentation boundaries for signs of lateral movement originating from router devices
• Periodically audit firmware versions across all D-Link devices in the environment

How to Mitigate CVE-2025-11408

Immediate Actions Required

• Restrict access to the D-Link DI-7001 MINI web management interface to trusted internal networks only
• Implement firewall rules to block external access to ports 80/443 on affected devices
• Review router configurations for signs of compromise and reset to factory defaults if tampering is suspected
• Segment affected routers from critical network infrastructure
• Monitor the D-Link Security Portal for firmware updates addressing this vulnerability

Patch Information

As of the last modification date (2025-11-19), no official patch has been released by D-Link for this vulnerability. Organizations should monitor D-Link's official security advisories for firmware updates. The vulnerability details are tracked in VulDB #327345, which may contain updated remediation information.

Until an official patch is available, implementing compensating controls such as network segmentation and access restrictions is critical to reduce exposure.

Workarounds

• Disable remote management access to the router's web interface if not required for operations
• Implement access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
• Deploy a VPN solution for remote administration rather than exposing the management interface directly
• Consider replacing affected devices with alternative hardware if patching timelines are not acceptable for your risk profile
• Use network monitoring tools to detect and block exploitation attempts at the perimeter

# Example firewall rule to restrict access to router management interface
# Block external access to management ports on D-Link device (example using iptables)
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
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP