CVE-2018-3716 in simplehttpserver
Summary
by MITRE
simplehttpserver node module suffers from a Cross-Site Scripting vulnerability to a lack of validation of file names.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/16/2020
The CVE-2018-3716 vulnerability affects the simplehttpserver node module, representing a significant security flaw that exposes applications to cross-site scripting attacks. This vulnerability stems from inadequate input validation mechanisms within the module's file name handling process, creating a pathway for malicious actors to inject arbitrary scripts into web applications. The issue manifests when the module processes file names without proper sanitization, allowing attackers to craft malicious file names that contain script code which gets executed in the context of other users' browsers. This type of vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a weakness in input validation that permits the execution of untrusted code within web applications. The vulnerability is particularly concerning because it directly impacts the security of web servers that rely on this module for serving static content, making it a critical concern for developers who implement simplehttpserver in production environments. The flaw operates by exploiting the trust relationship between the web server and client browsers, where user-supplied file names are not properly escaped or validated before being rendered in web pages.
The technical implementation of this vulnerability occurs when the simplehttpserver module accepts file names from user input without performing adequate sanitization checks. When a malicious user provides a file name containing script tags or other executable code, the module fails to validate or escape these inputs before displaying them in the web interface. This lack of proper input validation creates a situation where the browser interprets the malicious code as legitimate content rather than as harmful script. The vulnerability is particularly dangerous because it operates at the presentation layer of web applications, where user input is directly rendered without proper security context handling. Attackers can leverage this weakness by uploading or referencing files with malicious names that contain embedded javascript, allowing them to execute code in the context of other users who access these files through the vulnerable server. The exploit typically involves creating a file name that includes script tags or other malicious payloads, which are then served by the simplehttpserver module and executed in the browsers of unsuspecting users. This vulnerability directly maps to attack techniques described in the ATT&CK framework under the T1203 category of Exploitation for Client Execution, where adversaries leverage web application vulnerabilities to execute malicious code on target systems.
The operational impact of CVE-2018-3716 extends beyond simple script execution, potentially enabling more sophisticated attacks including session hijacking, data exfiltration, and privilege escalation within affected applications. Organizations using the simplehttpserver module may experience unauthorized access to user sessions, as attackers can steal cookies and session tokens through malicious script execution. The vulnerability also creates opportunities for attackers to perform man-in-the-middle attacks by injecting malicious code that can redirect users to phishing sites or capture sensitive information. Additionally, the flaw can be exploited to deface web applications, manipulate displayed content, or create persistent backdoors within the affected systems. The widespread use of simplehttpserver in development environments and testing scenarios means that many applications may be unknowingly exposed to this vulnerability, particularly those that do not implement proper input validation at the application level. Security teams must consider the potential for cascading effects, where this vulnerability could be leveraged as a stepping stone for more comprehensive attacks against network infrastructure or other connected systems. The vulnerability's impact is amplified in environments where the simplehttpserver module is used to serve content that includes user-generated data, as this creates multiple potential attack vectors for malicious input injection.
Mitigation strategies for CVE-2018-3716 require immediate attention through both code-level fixes and operational security measures. The primary solution involves implementing proper input validation and sanitization for all file names processed by the simplehttpserver module, ensuring that any user-supplied input is properly escaped before being rendered in web contexts. Developers should implement comprehensive validation routines that reject file names containing script tags, special characters, or other potentially malicious content. Organizations should consider upgrading to newer versions of the module that include proper input validation mechanisms or implementing custom sanitization functions that can be integrated into existing applications. Security measures should also include monitoring for suspicious file name patterns and implementing web application firewalls that can detect and block attempts to exploit this vulnerability. The remediation process must also involve thorough code reviews to ensure that all input handling within the application follows secure coding practices and adheres to established security standards such as those outlined in the OWASP Top Ten. Additionally, organizations should implement proper access controls and least privilege principles to limit the impact of potential exploitation, ensuring that even if an attacker successfully exploits this vulnerability, they cannot escalate privileges or access sensitive data beyond their initial foothold. Regular security assessments and penetration testing should be conducted to verify that the implemented mitigations are effective and to identify any additional vulnerabilities that may exist within the application's attack surface.