CVE-2017-12777 in NexusPHP
Summary
by MITRE
Cross-Site Scripting (XSS) exists in NexusPHP version v1.5 via some parameter to usersearch.php.
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Analysis
by VulDB Data Team • 11/06/2019
The vulnerability CVE-2017-12777 represents a cross-site scripting flaw discovered in NexusPHP version v1.5 that specifically affects the usersearch.php component. This type of vulnerability falls under the CWE-79 category, which defines cross-site scripting as a code injection attack that enables attackers to execute scripts in the victim's browser. The flaw manifests when user input parameters are not properly sanitized or validated before being processed and returned to the web application's output. In the context of NexusPHP, this vulnerability allows malicious actors to inject malicious scripts into the user search functionality, potentially compromising the security of all users interacting with the affected system.
The technical implementation of this XSS vulnerability occurs within the usersearch.php script where parameters received from user input are directly incorporated into the application's response without adequate sanitization measures. Attackers can exploit this by crafting malicious payloads that include script tags or other executable code within the search parameters. When the vulnerable application processes these inputs and displays them in the browser, the injected scripts execute in the context of the victim's session, potentially leading to session hijacking, credential theft, or other malicious activities. The vulnerability's impact is particularly concerning because it affects the core user search functionality, which is likely accessed frequently by legitimate users, amplifying the potential attack surface and execution opportunities.
The operational impact of CVE-2017-12777 extends beyond simple script execution as it represents a critical security weakness that can be leveraged for advanced persistent threats. According to ATT&CK framework category T1059, this vulnerability enables command and control through script injection techniques. Attackers can use the XSS flaw to establish persistent access to user sessions, potentially leading to unauthorized data access, privilege escalation, or even complete system compromise if the affected users have administrative privileges. The vulnerability affects the confidentiality, integrity, and availability of the web application by allowing unauthorized code execution in user browsers, which can result in data exfiltration, session manipulation, or redirection to malicious sites.
Mitigation strategies for CVE-2017-12777 should focus on implementing comprehensive input validation and output encoding mechanisms. The primary defense involves sanitizing all user-supplied input parameters before processing them within the usersearch.php script, utilizing proper HTML entity encoding for any output that may contain user data. Security measures should include implementing Content Security Policy (CSP) headers to limit script execution sources, employing proper parameter validation routines, and ensuring that all user input is treated as untrusted. Organizations should also consider implementing web application firewalls to detect and block malicious payloads, conducting regular security code reviews, and applying the latest security patches provided by the NexusPHP maintainers. Additionally, implementing proper session management practices and user access controls can help minimize the potential damage from successful XSS exploitation attempts, as outlined in the OWASP Top Ten security guidelines for web application protection.