CVE-2024-22651: D-Link DIR-815 Firmware RCE Vulnerability

CVE-2024-22651 Overview

CVE-2024-22651 is a critical command injection vulnerability discovered in the D-Link DIR-815 router firmware version 1.04. The vulnerability exists in the ssdpcgi_main function within the cgibin binary, allowing remote attackers to execute arbitrary commands on the affected device without authentication.

Critical Impact

This command injection vulnerability allows unauthenticated remote attackers to execute arbitrary system commands on vulnerable D-Link DIR-815 routers, potentially leading to complete device compromise, network infiltration, and use of the router in botnet operations.

Affected Products

• D-Link DIR-815 Router
• D-Link DIR-815 Firmware v1.04
• D-Link DIR-815 Firmware (all versions matching cpe:2.3:o:dlink:dir-815_firmware::::::::)

Discovery Timeline

• 2024-01-24 - CVE-2024-22651 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-22651

Vulnerability Analysis

This vulnerability is classified as CWE-77 (Improper Neutralization of Special Elements used in a Command), commonly known as command injection. The flaw resides in the ssdpcgi_main function of the router's cgibin binary, which handles SSDP (Simple Service Discovery Protocol) requests.

The vulnerability allows an attacker to inject and execute arbitrary operating system commands through the network interface without requiring any authentication. Due to the nature of embedded router firmware, commands typically execute with root privileges, giving attackers complete control over the device.

The attack can be launched remotely over the network with low complexity and requires no user interaction, making it particularly dangerous for internet-exposed devices.

Root Cause

The root cause of CVE-2024-22651 is improper input validation and sanitization in the ssdpcgi_main function. When processing SSDP-related requests, the function fails to properly neutralize special characters and shell metacharacters before passing user-controlled input to system command execution functions. This allows attackers to break out of the intended command context and inject malicious commands.

Attack Vector

The attack vector is network-based, targeting the SSDP service running on the D-Link DIR-815 router. An attacker can craft malicious SSDP requests containing shell metacharacters and command sequences that, when processed by the vulnerable ssdpcgi_main function, result in arbitrary command execution on the router.

The vulnerability manifests in how the cgibin binary processes incoming SSDP requests. When specially crafted input containing command injection payloads is sent to the router's SSDP handler, the unsanitized input is passed to system command execution routines, allowing the injected commands to be executed with the privileges of the web server process (typically root on embedded devices).

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

Detection Methods for CVE-2024-22651

Indicators of Compromise

• Unexpected outbound network connections from the router to unknown IP addresses
• Unusual processes running on the router that were not part of the original firmware
• Modified configuration files or unexpected user accounts on the device
• Network traffic anomalies indicating the router is participating in botnet activities or scanning operations

Detection Strategies

• Monitor SSDP traffic (UDP port 1900) for suspicious payloads containing shell metacharacters such as ;, |, &, $(), or backticks
• Implement network intrusion detection rules to identify command injection patterns in HTTP requests to router CGI endpoints
• Deploy SentinelOne Singularity to detect anomalous behavior patterns on network segments containing vulnerable devices
• Review router logs for unexpected CGI request patterns or error messages indicating command execution failures

Monitoring Recommendations

• Enable logging on network firewalls to capture traffic to and from D-Link DIR-815 routers
• Implement network segmentation to isolate IoT devices including routers from critical network segments
• Use SentinelOne's network visibility features to monitor for lateral movement attempts originating from compromised routers

How to Mitigate CVE-2024-22651

Immediate Actions Required

• Immediately check if your D-Link DIR-815 router is running firmware version 1.04 and prioritize replacement or isolation
• Restrict network access to the router's management interfaces from untrusted networks
• Disable UPnP and SSDP services if not required for your network operations
• Consider replacing the D-Link DIR-815 with a currently supported router model, as this device may be end-of-life

Patch Information

As of the last modification date (2024-11-21), no vendor advisory or official patch from D-Link has been identified for this vulnerability. The D-Link DIR-815 is a legacy device and may no longer receive security updates. Users are strongly encouraged to check the D-Link support website for any firmware updates and consider device replacement if no patch is available.

Workarounds

• Disable SSDP/UPnP functionality on the router if the feature is available in the administrative interface
• Place the router behind a firewall that blocks inbound SSDP requests (UDP port 1900) from untrusted networks
• Implement access control lists (ACLs) to restrict management access to trusted IP addresses only
• Consider deploying third-party firmware alternatives if available and supported for the DIR-815 model

# Example: Block SSDP traffic at the network perimeter
# iptables rule to drop inbound SSDP requests to vulnerable routers
iptables -A FORWARD -p udp --dport 1900 -d <router_ip> -j DROP

# Block UPnP discovery responses
iptables -A FORWARD -p udp --sport 1900 -s <router_ip> -j DROP