CVE-2017-9451 in flatCore
Summary
by MITRE
Cross site scripting (XSS) vulnerability in pages.edit_form.php in flatCore 1.4.6 allows remote attackers to inject arbitrary JavaScript via the PATH_INFO in an acp.php URL, due to use of unsanitized $_SERVER['PHP_SELF'] to generate URLs.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2017-9451 represents a critical cross site scripting flaw within the flatCore content management system version 1.4.6. This vulnerability exists in the pages.edit_form.php component and specifically targets the administrative control panel functionality. The issue stems from the application's improper handling of user input within the server environment variables, creating an avenue for malicious actors to execute arbitrary JavaScript code within the context of authenticated user sessions. The vulnerability is particularly concerning because it operates within the administrative interface, potentially allowing attackers to gain elevated privileges and compromise the entire system.
The technical root cause of this vulnerability lies in the improper sanitization of the $_SERVER['PHP_SELF'] variable within the acp.php URL handling mechanism. When the application processes requests through the PATH_INFO parameter, it directly incorporates this unsanitized server variable into URL generation without proper input validation or output encoding. This pattern creates a classic XSS vulnerability where attacker-controlled data flows from the PATH_INFO parameter through the PHP_SELF variable and ultimately into the rendered web page. The vulnerability maps directly to CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is used to generate web content without proper validation or encoding, resulting in execution of unintended code.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to manipulate the administrative interface and potentially access sensitive system information. An attacker could craft malicious PATH_INFO parameters that, when processed by the vulnerable flatCore application, would inject malicious JavaScript into the administrative forms. This could enable session hijacking, privilege escalation, or even complete system compromise if the attacker can leverage the administrative access to modify core system files or user permissions. The vulnerability affects all users with administrative access to the flatCore system, making it particularly dangerous in environments where multiple administrators have access to the platform.
Mitigation strategies for this vulnerability should focus on immediate input sanitization and output encoding practices. The primary fix involves implementing proper validation and sanitization of all server variables, particularly $_SERVER['PHP_SELF'], before incorporating them into URL generation logic. Organizations should also implement Content Security Policy headers to limit the execution of inline scripts and establish proper input validation mechanisms that prevent malicious data from entering the application's processing pipeline. Additionally, regular security audits of server-side include files and URL handling mechanisms should be conducted to identify similar patterns that might introduce XSS vulnerabilities. This vulnerability aligns with ATT&CK technique T1059.007 which covers the use of scripting languages to execute malicious code, and T1071.004 which addresses application layer protocol usage for command and control communications. The incident highlights the importance of following secure coding practices and implementing comprehensive input validation across all server-side applications to prevent such vulnerabilities from being exploited in production environments.