CVE-2023-20142 in Small Business RV016
Summary
by MITRE • 04/05/2023
Multiple vulnerabilities in the web-based management interface of Cisco Small Business RV016, RV042, RV042G, RV082, RV320, and RV325 Routers could allow an unauthenticated, remote attacker to conduct cross-site scripting (XSS) attacks against a user of the interface. These vulnerabilities are due to insufficient input validation by the web-based management interface. An attacker could exploit these vulnerabilities by sending crafted HTTP requests to an affected device and then persuading a user to visit specific web pages that include malicious payloads. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information. Cisco has not released software updates that address these vulnerabilities.
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Analysis
by VulDB Data Team • 08/25/2025
The vulnerability identified as CVE-2023-20142 represents a critical cross-site scripting weakness affecting Cisco Small Business routers including models RV016 RV042 RV042G RV082 RV320 and RV325. These devices operate with web-based management interfaces that serve as primary access points for network administration tasks. The flaw stems from inadequate input validation mechanisms within the web interface components that process user-supplied data. This insufficient sanitization creates an attack surface where malicious actors can inject harmful scripts into the router's management portal. The vulnerability is particularly concerning because it requires no authentication to exploit, making it accessible to any remote attacker who can reach the device's web interface. The affected models represent a significant portion of Cisco's small business routing solutions that are widely deployed in enterprise environments where network security is paramount.
The technical exploitation of this vulnerability follows a standard XSS attack pattern where an attacker crafts malicious HTTP requests designed to inject script code into the router's web interface. The attack vector leverages the web-based management interface's failure to properly validate and sanitize user input parameters. When a victim user navigates to a maliciously crafted web page that contains embedded payloads or when the router processes malformed input through its web interface, the injected scripts execute in the context of the authenticated user's browser session. This execution context allows attackers to perform actions such as stealing session cookies, modifying router configurations, accessing sensitive network information, or redirecting users to malicious sites. The vulnerability specifically targets the input validation mechanisms that should prevent malicious data from being processed and displayed within the web interface. According to CWE standards this vulnerability maps to CWE-79 which categorizes cross-site scripting flaws as weaknesses in web applications that allow attackers to inject client-side scripts into web pages viewed by other users.
The operational impact of this vulnerability extends beyond simple script execution to encompass significant security implications for affected networks. An attacker who successfully exploits these vulnerabilities could gain unauthorized access to router management functions, potentially leading to complete network compromise. The attack requires minimal privileges since no authentication is needed to initiate the exploit, and the attack surface is broad due to the widespread deployment of these router models. Organizations using affected Cisco routers face the risk of persistent threats where attackers can maintain access through session cookies or by establishing backdoors. The vulnerability also creates opportunities for more sophisticated attacks such as man-in-the-middle scenarios where attackers can intercept and manipulate network traffic. Network administrators may find their management interfaces compromised, leading to unauthorized configuration changes that could disrupt services or create security gaps. The lack of available software updates for this vulnerability means that affected organizations cannot rely on vendor-provided patches to resolve the issue, leaving them vulnerable to ongoing exploitation attempts.
Organizations affected by CVE-2023-20142 should implement immediate network segmentation to isolate affected routers from critical network segments. The recommended mitigation strategy involves deploying network access control measures that restrict access to router management interfaces to authorized administrative workstations only. Network administrators should consider implementing web application firewalls that can detect and block malicious script injection attempts targeting the affected web interfaces. Additional defensive measures include disabling unnecessary web management services when not actively required and implementing strict access controls through firewall rules that limit external access to router management ports. Security monitoring should focus on detecting anomalous traffic patterns that might indicate exploitation attempts or unauthorized access to the management interfaces. Organizations should also consider implementing network intrusion detection systems that can identify suspicious HTTP request patterns commonly associated with XSS attacks. The ATT&CK framework categorizes this vulnerability under T1059.007 for scripting and T1566.001 for spearphishing with attachments, indicating that exploitation typically involves user interaction and malicious payload delivery. Given the absence of vendor patches, organizations should also consider alternative security controls such as network monitoring tools that can detect malicious payloads in network traffic and implement security awareness training to prevent users from visiting compromised web pages. The vulnerability demonstrates the critical importance of input validation in web applications and highlights the need for comprehensive security testing of management interfaces in network infrastructure devices.