CVE-2017-16755 in HelpSpot
Summary
by MITRE
An issue was discovered in Userscape HelpSpot before 4.7.2. A reflected cross-site scripting vulnerability exists in the "return" parameter of the "index.php?pg=moderated" endpoint. It executes when the return link is clicked.
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Analysis
by VulDB Data Team • 01/06/2020
The vulnerability identified as CVE-2017-16755 represents a critical reflected cross-site scripting flaw within the Userscape HelpSpot platform prior to version 4.7.2. This security weakness resides in the web application's handling of user input through the "return" parameter of the specific endpoint index.php?pg=moderated. The vulnerability operates by leveraging the application's failure to properly sanitize or encode user-supplied data before incorporating it into dynamically generated web responses. When a user clicks on a return link that contains maliciously crafted input in the return parameter, the application reflects this unvalidated input back to the user's browser without adequate security measures.
The technical implementation of this vulnerability stems from the application's lack of input validation and output encoding mechanisms. When the system processes the return parameter, it directly incorporates the user-provided value into the HTTP response without proper sanitization. This creates an environment where an attacker can inject malicious scripts that execute in the context of the victim's browser. The reflected nature of this XSS vulnerability means that the malicious payload is delivered and executed through a crafted URL that the victim must click to trigger the attack. This makes the vulnerability particularly dangerous as it can be easily propagated through phishing campaigns or social engineering attacks.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal sensitive user information, and manipulate the application's functionality. Attackers could potentially redirect users to malicious websites, inject malicious content into the application interface, or execute scripts that harvest cookies and authentication tokens. The vulnerability affects the integrity and confidentiality of user data within the HelpSpot platform, potentially compromising the security of customer support interactions and sensitive business information. According to CWE classification, this vulnerability maps to CWE-79 which specifically addresses Cross-Site Scripting flaws, while the ATT&CK framework would categorize this under T1566 for Phishing and T1059 for Command and Scripting Interpreter techniques.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and output encoding measures. Organizations should ensure that all user-supplied input is thoroughly validated against a whitelist of acceptable characters and that any potentially dangerous characters are properly escaped or encoded before being included in web responses. The fix should involve updating the HelpSpot application to version 4.7.2 or later, which includes the necessary security patches. Additionally, implementing Content Security Policy headers and using proper HTTP response headers can provide additional layers of protection against XSS attacks. Security teams should also conduct regular security assessments and input validation reviews to identify similar vulnerabilities in other application components and establish robust web application security practices that align with industry standards such as OWASP Top Ten and NIST cybersecurity frameworks.