CVE-2024-20416: Cisco RV340/RV345 Router RCE Vulnerability

CVE-2024-20416 Overview

A vulnerability in the upload module of Cisco RV340 and RV345 Dual WAN Gigabit VPN Routers could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to insufficient boundary checks when processing specific HTTP requests. An attacker could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as the root user on the underlying operating system of the device.

Critical Impact

Authenticated attackers can achieve root-level code execution on affected Cisco VPN routers through crafted HTTP requests to the upload module, potentially compromising network security infrastructure.

Affected Products

• Cisco RV340 Dual WAN Gigabit VPN Router
• Cisco RV345 Dual WAN Gigabit VPN Router
• Cisco RV345P Dual WAN Gigabit POE VPN Router

Discovery Timeline

• 2024-07-17 - CVE CVE-2024-20416 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-20416

Vulnerability Analysis

This vulnerability exists within the upload module of Cisco's Small Business RV340 and RV345 series VPN routers. The core issue stems from improper length handling (CWE-130), where the application fails to properly validate buffer boundaries when processing HTTP request data. When an authenticated user submits a specially crafted HTTP request to the upload functionality, the insufficient boundary checks allow the attacker to manipulate memory in unintended ways.

The vulnerability is particularly concerning because successful exploitation grants the attacker root-level privileges on the underlying Linux-based operating system. This means an attacker could install persistent backdoors, intercept network traffic, pivot to internal network resources, or completely compromise the router's configuration and security posture.

While authentication is required to exploit this vulnerability (reducing the attack surface somewhat), many small business environments may have weak administrative credentials or shared access among multiple users, increasing the practical risk of exploitation.

Root Cause

The vulnerability is caused by improper length handling (CWE-130) in the upload module's HTTP request processing logic. The application fails to properly validate the length of user-supplied data before processing it, leading to insufficient boundary checks. This allows attackers to supply malformed input that bypasses expected constraints and ultimately achieves code execution in the context of the root user.

Attack Vector

The attack is conducted remotely over the network and requires the attacker to have valid authentication credentials for the device's web management interface. The attacker must craft specific HTTP requests targeting the upload module functionality. These requests contain malicious payloads that exploit the boundary check weakness. When processed by the vulnerable upload module, the crafted input triggers the vulnerability, allowing arbitrary code execution with root privileges.

The attack does not require user interaction beyond the attacker's own actions, and successful exploitation has high impact on both confidentiality and integrity of the affected system.

The vulnerability manifests in the HTTP request processing logic of the upload module. Due to insufficient boundary validation, crafted HTTP requests can bypass length checks and achieve code execution. For technical details on the specific vulnerable components and exploitation mechanics, refer to the Cisco Security Advisory.

Detection Methods for CVE-2024-20416

Indicators of Compromise

• Unusual HTTP POST requests to the router's upload module endpoints with abnormally large or malformed payloads
• Unexpected processes running with root privileges on the affected device
• Unauthorized configuration changes or new user accounts on the router
• Suspicious outbound network connections originating from the router to unknown external hosts

Detection Strategies

• Monitor web management interface access logs for anomalous HTTP requests targeting upload functionality
• Implement network-based intrusion detection rules to identify exploitation attempts against Cisco RV340/RV345 routers
• Deploy endpoint detection and response (EDR) solutions to monitor for post-exploitation behaviors on network infrastructure
• Enable and review authentication logs for failed or unusual login attempts to router management interfaces

Monitoring Recommendations

• Configure SIEM alerts for multiple failed authentication attempts followed by successful login to router management interfaces
• Establish baseline network behavior for router management traffic and alert on deviations
• Monitor router CPU and memory utilization for anomalies that may indicate exploitation or post-compromise activity
• Implement regular configuration audits to detect unauthorized changes to router settings

How to Mitigate CVE-2024-20416

Immediate Actions Required

• Review the official Cisco Security Advisory and apply any available firmware updates immediately
• Restrict access to the router's web management interface to trusted IP addresses only
• Audit all administrative accounts and enforce strong, unique passwords
• Disable remote management access if not strictly required for operations
• Implement network segmentation to limit the blast radius if the device is compromised

Patch Information

Cisco has released security guidance for this vulnerability. Administrators should consult the Cisco Security Advisory for specific firmware versions that address this vulnerability and upgrade instructions. Due to the nature of the vulnerability allowing root-level code execution, patching should be prioritized for all affected devices.

Workarounds

• Restrict management interface access to specific trusted IP addresses using access control lists (ACLs)
• Disable the web-based management interface and use SSH/CLI for administration if feasible
• Place the router's management interface on a dedicated management VLAN with strict access controls
• Implement VPN-only access to the management interface for remote administration needs

# Example: Restrict management access via ACL (consult Cisco documentation for exact syntax)
# Configure access list to permit only trusted management hosts
access-list MGMT-ACCESS permit ip host 192.168.1.100 any
access-list MGMT-ACCESS deny ip any any log

# Apply to management interface (configuration varies by firmware version)
# Refer to Cisco documentation for your specific firmware