CVE-2017-8763 in epesi
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in modules/Base/Box/check_for_new_version.php in EPESI in Telaxus/EPESI 1.8.2 and earlier allows remote attackers to inject arbitrary web script or HTML via a crafted URI that lacks the cid parameter.
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Analysis
by VulDB Data Team • 12/06/2022
The vulnerability identified as CVE-2017-8763 represents a critical cross-site scripting flaw located within the EPESI content management system version 1.8.2 and earlier. This issue resides in the modules/Base/Box/check_for_new_version.php file, which serves as a component responsible for checking version updates within the application. The flaw stems from insufficient input validation and sanitization of URI parameters, specifically when the cid parameter is absent from the request. This oversight creates an exploitable condition that allows remote attackers to inject malicious web scripts or HTML content directly into the application's response.
The technical implementation of this vulnerability demonstrates a classic XSS attack vector where the application fails to properly escape or validate user-supplied input before rendering it in the browser context. When a malicious actor crafts a URI without the required cid parameter, the application processes the incomplete request and incorporates the unsanitized input into its output, thereby enabling script execution in the victim's browser. This particular weakness aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities in software applications. The vulnerability operates at the presentation layer of the application, where user input directly influences the generation of dynamic web content without adequate security controls.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to execute arbitrary code within the context of authenticated users' browsers. This could lead to session hijacking, credential theft, data exfiltration, or the deployment of additional malicious payloads through the compromised user sessions. Attackers could leverage this vulnerability to establish persistent access to the EPESI system, particularly if users with administrative privileges interact with the vulnerable endpoint. The attack requires no authentication and can be executed through simple web browser requests, making it particularly dangerous in environments where multiple users interact with the application. This vulnerability also maps to ATT&CK technique T1566, which covers the use of malicious web content to compromise systems.
Mitigation strategies for CVE-2017-8763 should prioritize immediate application updates to versions that address the input validation issues in the check_for_new_version.php module. Organizations should implement comprehensive input validation and sanitization measures that enforce proper parameter checking and reject requests lacking required parameters. The implementation of Content Security Policy headers can provide additional defense-in-depth measures to prevent script execution even if the primary vulnerability is exploited. Regular security auditing of URI parameter handling and input validation routines should be conducted to identify similar weaknesses in other application components. Additionally, network-based intrusion detection systems should be configured to monitor for suspicious URI patterns that may indicate exploitation attempts targeting this specific vulnerability. The remediation process should also include user education regarding the importance of avoiding untrusted web content and maintaining updated software versions to prevent exploitation of known vulnerabilities.