CVE-2017-6489 in epesi
Summary
by MITRE
Multiple Cross-Site Scripting (XSS) issues were discovered in EPESI 1.8.1.1. The vulnerabilities exist due to insufficient filtration of user-supplied data (element, state, cat, id, cid) passed to the EPESI-master/modules/Utils/Watchdog/subscribe.php URL. An attacker could execute arbitrary HTML and script code in a browser in the context of the vulnerable website.
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Analysis
by VulDB Data Team • 09/04/2020
The vulnerability identified as CVE-2017-6489 represents a critical cross-site scripting flaw within EPESI version 1.8.1.1, a web-based customer relationship management system. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing. The vulnerability specifically affects the EPESI-master/modules/Utils/Watchdog/subscribe.php endpoint, which serves as a subscription module for system notifications and monitoring features. Attackers can exploit this flaw by injecting malicious scripts through parameters including element, state, cat, id, and cid, which are all processed without adequate sanitization measures. The vulnerability aligns with CWE-79, which categorizes cross-site scripting as a code injection flaw that allows attackers to execute client-side scripts in the context of other users' browsers.
The technical exploitation of this vulnerability occurs when user input flows directly into the web application's output without proper encoding or validation. When an attacker crafts malicious payloads and submits them through the affected parameters, the application fails to filter or escape special characters that could be interpreted as HTML or JavaScript code. This allows the injected scripts to execute within the victim's browser session, potentially leading to session hijacking, data theft, or further compromise of the affected system. The attack vector is particularly concerning because it operates at the application layer and requires no elevated privileges from the attacker, making it accessible to anyone who can interact with the vulnerable web interface. The flaw demonstrates poor input validation practices that violate fundamental web security principles and can be categorized under the ATT&CK framework as a code injection technique targeting web applications.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling sophisticated attack chains that could compromise entire user sessions and sensitive data. An attacker could craft malicious payloads that redirect users to phishing sites, steal authentication cookies, or even inject additional malicious code that persists across multiple user sessions. The Watchdog module's subscription functionality makes this particularly dangerous as it likely serves legitimate users who trust the system's security. Organizations using EPESI 1.8.1.1 could face unauthorized access to customer data, system compromise, and potential regulatory violations if user sessions are hijacked. The vulnerability's persistence across multiple parameters increases the attack surface and reduces the effectiveness of simple parameter-based mitigations, requiring comprehensive input validation across all affected entry points.
Mitigation strategies for CVE-2017-6489 must focus on implementing robust input validation and output encoding mechanisms throughout the application. Organizations should immediately apply the vendor-provided patches or upgrade to a newer version of EPESI that addresses this vulnerability. In the interim, administrators can implement input sanitization measures that filter or escape special characters from user-supplied data before processing, particularly targeting the element, state, cat, id, and cid parameters. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against script execution, though this should not replace proper input validation. Regular security audits and automated vulnerability scanning should be conducted to identify similar issues in other application components. The remediation approach should follow security best practices outlined in OWASP's web application security guidelines, emphasizing the importance of defensive programming techniques and proper data handling procedures to prevent similar vulnerabilities from emerging in future development cycles.