CVE-2017-6491 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 (tooltip_id, callback, args, cid) passed to the EPESI-master/modules/Utils/Tooltip/req.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-2017-6491 represents a critical cross-site scripting flaw in EPESI version 1.8.1.1, a web-based customer relationship management system. This 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/Tooltip/req.php endpoint which accepts multiple parameters including tooltip_id, callback, args, and cid. These parameters are directly incorporated into the application's response without proper sanitization, creating an environment where malicious actors can inject arbitrary HTML and JavaScript code. The flaw operates at the application layer and can be exploited through web-based attacks targeting the vulnerable web application.
The technical implementation of this vulnerability aligns with CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is incorporated into web pages without proper validation or encoding. The affected parameters are processed by the tooltip module without adequate sanitization, allowing attackers to craft malicious payloads that will execute in the context of other users' browsers. The vulnerability demonstrates a classic case of improper input handling where user-supplied parameters are directly reflected in the application's output, creating a persistent XSS vector. Attackers can leverage this flaw by manipulating the tooltip_id, callback, args, or cid parameters to inject malicious scripts that will execute when other users view the affected pages.
The operational impact of CVE-2017-6491 extends beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal user credentials, redirect victims to malicious sites, or perform actions on behalf of authenticated users. The vulnerability affects all users interacting with the EPESI application, particularly those who have access to the tooltip functionality. Depending on the privileges of affected users, attackers could potentially escalate their access to gain administrative control over the system. The attack surface is broad since the vulnerability affects core application functionality and can be exploited through various vectors including email links, web forms, or direct URL manipulation. This type of vulnerability is particularly dangerous in enterprise environments where sensitive business data is stored and accessed through the application.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and output encoding mechanisms. The most effective approach involves sanitizing all user-supplied parameters before they are processed or rendered in the application's response. This includes implementing strict validation for the tooltip_id, callback, args, and cid parameters to ensure they conform to expected formats and do not contain malicious code. The implementation should follow secure coding practices as outlined in the OWASP Top Ten and MITRE ATT&CK framework for web application security. Organizations should also consider implementing Content Security Policy (CSP) headers to limit script execution and prevent unauthorized code injection. The recommended remediation includes updating to a patched version of EPESI, implementing proper parameter validation, and conducting comprehensive security testing to identify similar vulnerabilities in other application components. Additionally, regular security assessments and input validation reviews should be conducted to prevent similar issues from emerging in future versions.