CVE-2020-3590 in SD-WAN vManage
Summary
by MITRE • 11/07/2020
A vulnerability in the web-based management interface of the Cisco SD-WAN vManage Software could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user. The vulnerability exists because the web-based management interface does not properly validate user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or access sensitive, browser-based information.
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Analysis
by VulDB Data Team • 12/03/2020
The vulnerability identified as CVE-2020-3590 affects the Cisco SD-WAN vManage software, which serves as the centralized management platform for Cisco's software-defined wide area networking solutions. This web-based management interface represents a critical control point for network administrators to configure and monitor their SD-WAN environments, making it an attractive target for malicious actors seeking to compromise network security. The vManage software operates as a central hub for managing multiple network devices, including routers and switches, across distributed enterprise networks, which amplifies the potential impact of exploitation. The vulnerability resides within the web interface's input validation mechanisms, specifically failing to properly sanitize user-supplied data before processing or rendering within the application's user interface.
The technical flaw manifests as a classic cross-site scripting vulnerability classified under CWE-79, which occurs when the application fails to validate or escape user-provided input before incorporating it into dynamic web content. In this case, the web-based management interface processes user-supplied data without adequate sanitization, allowing malicious input to be executed as scripts within the browser context of authenticated users. The vulnerability requires an authenticated attacker with valid credentials to the vManage interface, but the exploitation vector is particularly dangerous because it leverages social engineering techniques to convince victims to click malicious links. The attacker can craft specially designed URLs or content that, when clicked by an authenticated user, executes arbitrary JavaScript code within the victim's browser session.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to access sensitive browser-based information and potentially escalate their privileges within the management interface. An attacker who successfully exploits this vulnerability could gain the ability to view, modify, or delete network configuration data, access administrative functions, or extract sensitive information from the browser session. This includes potential access to network credentials, device configurations, and other confidential data that administrators might have in their browser cache or session storage. The attack requires user interaction through a malicious link, but once executed, it can provide persistent access to the compromised management interface, allowing for extended surveillance or manipulation of the SD-WAN environment.
Security practitioners should implement multiple layers of mitigation to address this vulnerability, beginning with immediate patching of affected vManage software versions. Organizations should also enforce strict input validation across all web applications and implement Content Security Policy headers to limit script execution capabilities. Network segmentation and monitoring of management interface access can help detect anomalous behavior indicative of exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, specifically web shells, and represents a common vector for privilege escalation attacks. Regular security assessments of web applications, including thorough input validation testing and automated vulnerability scanning, should be implemented to prevent similar issues in the future. Organizations should also consider implementing web application firewalls to provide additional protection against XSS attacks and establish incident response procedures specifically addressing management interface compromises.