CVE-2017-6490 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 (cid, value, element, mode, tab, form_name, id) passed to the EPESI-master/modules/Utils/RecordBrowser/grid.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-2017-6490 represents a critical cross-site scripting flaw in EPESI version 1.8.1.1 that stems from inadequate input validation mechanisms within the application's record browser functionality. This weakness specifically affects the grid.php module located at EPESI-master/modules/Utils/RecordBrowser/grid.php, where user-supplied parameters including cid, value, element, mode, tab, form_name, and id are processed without proper sanitization. The absence of robust data filtration creates an exploitable condition that allows malicious actors to inject malicious scripts into the application's response, potentially compromising user sessions and data integrity.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP parameters that are directly passed to the vulnerable script without adequate validation or encoding. When a user interacts with the application's record browser interface, the system processes these parameters and incorporates them into dynamic HTML content without proper escaping mechanisms. This creates a persistent XSS vector where an attacker can craft malicious payloads that execute in the context of other users' browsers, effectively allowing for session hijacking, credential theft, and unauthorized data manipulation. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws resulting from insufficient input validation and output encoding.
From an operational standpoint, this vulnerability poses significant risks to organizations utilizing EPESI 1.8.1.1 as it enables attackers to execute arbitrary code in users' browsers, potentially leading to complete system compromise. The impact extends beyond simple script execution as attackers can leverage this vulnerability to steal session cookies, redirect users to malicious sites, or inject backdoors for persistent access. The attack surface is particularly concerning given that the vulnerable parameters are commonly used within the application's core functionality, making exploitation relatively straightforward for threat actors with basic knowledge of web application security principles. This vulnerability directly maps to ATT&CK technique T1566.001 which involves the use of malicious HTML content to execute code in user browsers.
Mitigation strategies for CVE-2017-6490 should prioritize immediate implementation of input validation and output encoding mechanisms within the vulnerable application components. Organizations must ensure that all user-supplied parameters are properly sanitized and encoded before being incorporated into dynamic content, with particular attention to the specific parameters mentioned in the vulnerability description. The recommended approach includes implementing strict input validation routines that reject or sanitize potentially malicious content, combined with proper HTML encoding of all dynamic output. Additionally, organizations should consider implementing Content Security Policy headers to provide an additional layer of protection against XSS attacks. The most effective long-term solution involves upgrading to a patched version of EPESI or implementing comprehensive web application firewall rules that can detect and block malicious payloads targeting these specific parameters. Security teams should also conduct thorough penetration testing to identify similar vulnerabilities in other application components that may share similar input handling patterns.