CVE-2017-11195 in Pulse Connect Secure
Summary
by MITRE
Pulse Connect Secure 8.3R1 has Reflected XSS in launchHelp.cgi. The helpLaunchPage parameter is reflected in an IFRAME element, if the value contains two quotes. It properly sanitizes quotes and tags, so one cannot simply close the src with a quote and inject after that. However, an attacker can use javascript: or data: to abuse this.
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Analysis
by VulDB Data Team • 10/25/2019
The vulnerability CVE-2017-11195 affects Pulse Connect Secure version 8.3R1 and represents a reflected cross-site scripting flaw in the launchHelp.cgi component. This issue specifically manifests when processing the helpLaunchPage parameter within an iframe element, creating a potential attack vector that could be exploited by malicious actors to execute arbitrary JavaScript code in the context of authenticated users' browsers. The vulnerability resides in how the application handles user input when constructing iframe src attributes, making it particularly dangerous as it can be leveraged to perform actions on behalf of legitimate users.
The technical implementation of this vulnerability stems from the application's insufficient input validation and sanitization mechanisms. While the system does attempt to sanitize quotes and HTML tags, this protection mechanism can be bypassed through the use of javascript: or data: URI schemes. When an attacker crafts a malicious payload containing these schemes, they can effectively circumvent the existing sanitization controls and inject executable code directly into the iframe's src attribute. This bypass occurs because the application's sanitization does not adequately address these specific URI schemes that can be used to execute JavaScript code within the browser context. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, and more precisely maps to CWE-749 which deals with dangerous methods or functions that can lead to code execution.
The operational impact of this vulnerability is significant as it allows attackers to perform a range of malicious activities including session hijacking, credential theft, and unauthorized access to sensitive information. An attacker could potentially redirect users to malicious websites, inject malware, or steal session cookies that would allow them to impersonate legitimate users. The reflected nature of the vulnerability means that the attack requires user interaction, typically through a specially crafted link sent via phishing emails or social engineering tactics. Once a user clicks on the malicious link, the JavaScript code executes in their browser context, potentially leading to complete compromise of their session and access to the Pulse Connect Secure environment.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding mechanisms. Organizations should ensure that all user-supplied input is properly sanitized and that the application enforces strict validation of URI schemes and protocols. The implementation of Content Security Policy headers can provide additional protection by restricting the sources from which scripts can be loaded. Additionally, upgrading to patched versions of Pulse Connect Secure is essential as vendors typically release security patches that address such vulnerabilities. Regular security testing including dynamic application security testing and manual penetration testing should be conducted to identify similar issues. The vulnerability also aligns with ATT&CK technique T1566 which covers social engineering attacks, as the exploitation often requires user interaction through crafted malicious links, making user education and awareness programs crucial components of the overall security posture.