CVE-2017-14534 in NexusPHP
Summary
by MITRE
Cross Site Scripting (XSS) exists in NexusPHP 1.5.beta5.20120707 via the PATH_INFO to location.php, related to PHP_SELF.
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability CVE-2017-14534 represents a cross site scripting flaw identified in NexusPHP version 1.5.beta5.20120707, specifically within the location.php script that processes PATH_INFO parameters. This issue arises from the improper handling of user-supplied input that originates from the PHP_SELF server variable, which contains the path of the current script being executed. The vulnerability manifests when the application fails to adequately sanitize or escape data derived from the PATH_INFO component of the URL, allowing malicious actors to inject arbitrary JavaScript code into the application's response.
The technical exploitation of this vulnerability occurs through manipulation of the PATH_INFO parameter in the HTTP request, where an attacker can craft malicious input that gets processed by the location.php script without proper input validation or output encoding. When the application incorporates the unfiltered PATH_INFO data into the HTML response, particularly when referencing PHP_SELF, it creates an XSS vector that can be leveraged by attackers to execute malicious scripts in the context of the victim's browser. This type of vulnerability falls under CWE-79 which specifically addresses cross site scripting flaws in web applications, where insufficient validation or sanitization of user-provided data allows for script injection attacks.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it provides attackers with the capability to perform various malicious activities including but not limited to cookie theft, defacement of web pages, redirection to malicious sites, and potential privilege escalation within the application context. The vulnerability affects users who interact with the NexusPHP application, particularly those who might be tricked into clicking malicious links or visiting compromised pages that exploit this XSS vector. Attackers can leverage this flaw to execute persistent XSS attacks against unsuspecting users, potentially compromising sensitive information and user sessions within the application's environment.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and output encoding mechanisms throughout the application. The recommended approach involves sanitizing all user-supplied data, particularly parameters derived from PATH_INFO and PHP_SELF, before incorporating them into the application's response. Implementing Content Security Policy headers can provide additional protection against XSS attacks by restricting script execution within the browser context. Additionally, developers should adopt secure coding practices such as using proper HTML escaping functions when outputting dynamic content and implementing proper parameter validation to prevent malicious input from being processed by the application. This vulnerability also highlights the importance of regular security assessments and code reviews to identify similar issues in legacy applications, as the ATT&CK framework categorizes such issues under the execution and persistence tactics that attackers commonly exploit to maintain access within compromised systems.