CVE-2018-16484 in m-server
Summary
by MITRE
A XSS vulnerability was found in module m-server <1.4.2 that allows malicious Javascript code or HTML to be executed, due to the lack of escaping for special characters in folder names.
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Analysis
by VulDB Data Team • 05/07/2020
The vulnerability identified as CVE-2018-16484 represents a cross-site scripting flaw within the m-server module version 1.4.1 and earlier, constituting a significant security risk for web applications that rely on this component. This issue arises from inadequate input validation and sanitization mechanisms that fail to properly escape special characters in folder names, creating an environment where malicious actors can inject harmful scripts into the application's response handling. The vulnerability specifically targets the server-side processing of directory structures where folder names are directly incorporated into web responses without proper sanitization, making it particularly dangerous in environments where user-supplied directory names are accepted or processed.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious folder names containing special characters that, when processed by the vulnerable m-server module, are not properly escaped before being rendered in web pages. This allows javascript code or html content to be executed within the context of the victim's browser session, potentially enabling session hijacking, credential theft, or other malicious activities. The flaw directly maps to CWE-79, which describes Cross-Site Scripting vulnerabilities resulting from insufficient escaping of special characters in output contexts. The vulnerability's impact is amplified by the fact that it occurs at the folder name processing level, meaning that any directory structure manipulation could potentially serve as an attack vector, regardless of whether the folder names are user-controlled or system-generated.
The operational impact of CVE-2018-16484 extends beyond simple script execution, as it can enable attackers to manipulate web application behavior and potentially gain unauthorized access to sensitive resources. In environments where m-server is used for content management or file organization, attackers could exploit this vulnerability to inject persistent scripts that would execute whenever users browse to affected directories. The vulnerability also aligns with ATT&CK technique T1213, which covers data from information repositories, as attackers could potentially use this flaw to access or manipulate stored content through manipulated directory structures. Organizations using vulnerable versions of m-server face risks of data compromise, service disruption, and potential lateral movement within their network infrastructure.
Mitigation strategies for this vulnerability should prioritize immediate patching of the m-server module to version 1.4.2 or later, which includes proper input sanitization and escaping mechanisms for folder names. Security teams should implement comprehensive input validation at all levels of the application stack, ensuring that special characters in directory names are properly escaped or encoded before any rendering occurs. Additionally, organizations should deploy web application firewalls and input filtering mechanisms to detect and block suspicious directory name patterns that could indicate attempted exploitation. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the application architecture, as this type of flaw often indicates broader input validation issues that may exist elsewhere in the system. The vulnerability serves as a reminder of the critical importance of proper output escaping and input sanitization in web applications, particularly when handling user-supplied data in contexts where it will be rendered in browser environments.