CVE-2020-3345 in Webex Meetings
Summary
by MITRE
A vulnerability in certain web pages of Cisco Webex Meetings and Cisco Webex Meetings Server could allow an unauthenticated, remote attacker to modify a web page in the context of a browser. The vulnerability is due to improper checks on parameter values within affected pages. An attacker could exploit this vulnerability by persuading a user to follow a crafted link that is designed to pass HTML code into an affected parameter. A successful exploit could allow the attacker to alter the contents of a web page to redirect the user to potentially malicious web sites, or the attacker could leverage this vulnerability to conduct further client-side attacks.
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Analysis
by VulDB Data Team • 11/04/2020
This vulnerability resides within Cisco Webex Meetings and Cisco Webex Meetings Server web applications, representing a critical security flaw that undermines the integrity of web page content. The issue stems from insufficient input validation mechanisms that fail to properly sanitize parameter values passed through web requests. According to CWE-79, this vulnerability constitutes a classic cross-site scripting (XSS) weakness where malicious HTML code can be injected into web pages through improperly validated user inputs. The flaw specifically affects web pages that process user-supplied parameters without adequate sanitization, creating an attack vector that allows remote exploitation without authentication requirements.
The exploitation mechanism leverages social engineering tactics where attackers craft malicious links designed to inject HTML content into vulnerable parameters within the web application. This technique enables attackers to perform persistent XSS attacks by manipulating the web page content in the user's browser context. The vulnerability's impact extends beyond simple content modification as it provides a foothold for more sophisticated client-side attacks including session hijacking, credential theft, and redirection to malicious domains. The attack requires minimal privileges since no authentication is needed to exploit the vulnerability, making it particularly dangerous in environments where users frequently interact with web-based meeting platforms.
From an operational standpoint, this vulnerability poses significant risks to enterprise security environments where Cisco Webex is extensively deployed for remote collaboration. The ability to modify web page content in real-time creates opportunities for attackers to establish persistent footholds within organizational networks. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566 for phishing, as attackers can leverage this weakness to create convincing malicious redirects that appear legitimate to end users. Organizations relying on these platforms face potential data exfiltration, unauthorized access to meeting resources, and compromise of user sessions through the exploitation of this vulnerability.
Mitigation strategies should focus on implementing comprehensive input validation and output encoding mechanisms across all web application parameters. Organizations must ensure that all user-supplied inputs undergo strict sanitization before being processed or rendered in web pages. The implementation of Content Security Policy (CSP) headers can provide additional protection against malicious script execution, while regular security assessments should be conducted to identify similar vulnerabilities in web applications. Cisco has released patches addressing this vulnerability through security updates that should be deployed immediately, and network segmentation can help limit the potential impact of successful exploitation attempts. Regular user education regarding suspicious links and phishing attempts remains crucial in defending against social engineering components of this attack vector.