CVE-2025-60676: D-Link DIR-878 Firmware RCE Vulnerability

CVE-2025-60676 Overview

CVE-2025-60676 is an unauthenticated command injection vulnerability in the D-Link DIR-878A1 router running firmware FW101B04.bin. The flaw resides in the SetNetworkSettings handler of prog.cgi, where the IPAddress and SubnetMask parameters are concatenated directly into a shell command executed via system(). A remote attacker can send a crafted HTTP request without credentials to execute arbitrary operating system commands on the device. The issue is classified under CWE-77: Improper Neutralization of Special Elements used in a Command.

Critical Impact
Unauthenticated remote attackers can inject arbitrary shell commands into the router's underlying operating system by targeting the network settings endpoint of prog.cgi.

Affected Products

D-Link DIR-878 hardware revision A1
D-Link DIR-878 firmware version 1.01B04 (FW101B04.bin)
Deployments exposing the router web management interface

Discovery Timeline

2025-11-13 - CVE-2025-60676 published to the National Vulnerability Database
2026-07-05 - Last updated in NVD database

Technical Details for CVE-2025-60676

Vulnerability Analysis

The DIR-878A1 web management interface exposes a CGI endpoint at prog.cgi that handles LAN configuration through the SetNetworkSettings action. When the router processes this request, it reads the attacker-supplied IPAddress and SubnetMask values and interpolates them into a shell command string. The resulting string is then passed to system(), which invokes /bin/sh and executes any shell metacharacters embedded in the input.

The endpoint does not require authentication, so any host that can reach the web interface can trigger the injection. Command execution occurs in the context of the web server process, which on consumer D-Link routers typically runs as root. This grants the attacker full control over network traffic, credentials stored on the device, and any downstream LAN clients.

Root Cause

The vulnerability stems from unsafe string concatenation of untrusted HTTP parameters into a command line. The handler treats IPAddress and SubnetMask as opaque strings and does not validate their format against an IPv4 dotted-quad pattern. It also does not escape shell metacharacters such as ;, |, `, or $(). Combined with the use of system() instead of execve() with an argument vector, the code path allows arbitrary shell interpretation.

Attack Vector

Exploitation requires only network reachability to the router's HTTP management service. An attacker submits a POST request to prog.cgi invoking the SetNetworkSettings action with a payload that appends shell metacharacters to the IPAddress or SubnetMask field. When the CGI handler builds the command string, the injected characters break out of the intended argument context and execute attacker-controlled commands. Public proof-of-concept material is documented in the GitHub PoC for CVE-2025-60676.

Detailed exploitation payloads are described in the referenced advisory. No verified exploit code is reproduced here.

Detection Methods for CVE-2025-60676

Indicators of Compromise

HTTP POST requests to /prog.cgi containing the SetNetworkSettings action from external or unexpected internal sources
IPAddress or SubnetMask parameter values containing shell metacharacters such as ;, &, |, backticks, or $()
Unexpected outbound connections from the router to attacker infrastructure following configuration requests
New processes such as wget, curl, tftp, or nc spawned by the router web server

Detection Strategies

Inspect web server and CGI access logs for POST requests to prog.cgi with abnormal parameter content
Deploy network intrusion detection signatures that match shell metacharacters in HTTP parameters destined for D-Link management URIs
Baseline outbound traffic from routers and alert on connections to non-ISP destinations, especially on ports 4444, 1337, or arbitrary high ports

Monitoring Recommendations

Restrict management interface exposure to trusted management VLANs and log all administrative HTTP sessions
Forward router syslog data to a centralized logging platform and retain configuration change events
Monitor DNS queries originating from the router for anomalous domains associated with botnet command-and-control

How to Mitigate CVE-2025-60676

Immediate Actions Required

Disable remote (WAN-side) management of the DIR-878A1 web interface
Restrict LAN-side access to the management interface using firewall rules or a dedicated management network
Rotate administrative credentials and Wi-Fi pre-shared keys after confirming device integrity
Consult the D-Link Security Bulletin for the current support status of the DIR-878A1

Patch Information

At the time of publication, the enriched advisory data does not reference a fixed firmware version for the DIR-878A1. The DIR-878 line has previously been declared end-of-support in some regions. Administrators should check the D-Link Security Bulletin and the D-Link Official Website for updated firmware or end-of-life guidance before deciding whether to patch or replace the device.

Workarounds

Replace the DIR-878A1 with a currently supported router if no firmware fix is available
Place the router behind an upstream firewall that blocks inbound HTTP and HTTPS to the management interface
Segment IoT and untrusted client networks from the management VLAN to limit lateral reach if the device is compromised
Disable UPnP and any cloud management features that expose the device to the internet

bash

# Example: block WAN access to the router management interface on an upstream firewall
iptables -I FORWARD -p tcp -d <router_wan_ip> --dport 80 -j DROP
iptables -I FORWARD -p tcp -d <router_wan_ip> --dport 443 -j DROP