CVE-2019-1685 in Unity Connection
Summary
by MITRE
A vulnerability in the Security Assertion Markup Language (SAML) single sign-on (SSO) interface of Cisco Unity Connection could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface of an affected device. The vulnerability is due to insufficient validation of user-supplied input by the interface of an affected device. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. 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. Version 12.5 is affected.
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Analysis
by VulDB Data Team • 07/19/2023
The vulnerability identified as CVE-2019-1685 represents a critical cross-site scripting flaw within Cisco Unity Connection's Security Assertion Markup Language SSO interface. This weakness specifically targets the authentication and authorization mechanisms that enable single sign-on functionality for enterprise communication systems. The affected version 12.5 demonstrates a fundamental failure in input validation processes that allows malicious actors to inject harmful script code into the web interface. The vulnerability stems from inadequate sanitization of user-supplied data within the SAML authentication flow, creating an attack surface where unauthenticated remote adversaries can manipulate the system through crafted web requests.
The technical exploitation of this vulnerability relies on social engineering techniques where attackers craft malicious links designed to trigger XSS payloads when clicked by authenticated users. This type of attack leverages the trust relationship between the user and the affected interface, as users typically do not suspect legitimate-looking links that contain malicious script code. The flaw operates at the application layer where user input is processed without proper validation, allowing attackers to inject JavaScript code that executes within the user's browser context. The SAML protocol itself is designed to facilitate secure authentication across different systems, but the implementation weakness in Unity Connection's interface creates a dangerous gap in the security model.
The operational impact of this vulnerability extends beyond simple script execution, as successful exploitation could lead to complete session hijacking and unauthorized access to sensitive information. Attackers could potentially steal user credentials, access confidential communication data, or manipulate the SAML authentication process to gain broader network access. The browser-based nature of the attack means that compromised sessions could be used to access other systems within the same trust domain, creating potential lateral movement opportunities for threat actors. This vulnerability particularly affects organizations relying on Cisco Unity Connection for enterprise communication, as the attack requires no prior authentication credentials and can target any user with access to the affected interface.
Security professionals should consider this vulnerability in the context of CWE-79 which specifically addresses cross-site scripting flaws in web applications. The attack vector aligns with ATT&CK technique T1566 which covers social engineering through malicious links and payloads. Organizations must implement immediate mitigations including input validation improvements, content security policy enforcement, and user education programs to reduce the risk of successful exploitation. Cisco has released patches addressing this vulnerability, and administrators should prioritize updating their Unity Connection installations to prevent potential compromise of enterprise communication systems. The broader implications suggest that similar vulnerabilities may exist in other SAML implementations, requiring comprehensive security assessments of authentication infrastructure components.