CVE-2019-5458 in http-file-server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in http-file-server (all versions) allows an attacker with access to the server file system to execute arbitrary JavaScript code in victim's browser.
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Analysis
by VulDB Data Team • 11/14/2023
The CVE-2019-5458 vulnerability represents a critical cross-site scripting flaw in http-file-server software across all versions, fundamentally compromising web application security. This vulnerability arises from insufficient input validation and output encoding within the file server's web interface, creating a pathway for malicious actors to inject persistent JavaScript payloads. The flaw specifically manifests when the server processes user-supplied filenames or directory listings that contain malicious script code, which then executes in the context of victim browsers without proper sanitization mechanisms.
The technical exploitation of this vulnerability occurs through manipulation of file system paths or names that contain script tags or executable JavaScript code. When victims browse the affected file server interface, the malicious content is rendered directly into the web page without appropriate HTML escaping or content security policy enforcement. This allows attackers who have compromised server file system access to inject persistent XSS payloads that can steal session cookies, perform unauthorized actions, or redirect users to malicious domains. The vulnerability operates at the application layer and specifically targets the server's file listing functionality where filenames are displayed to users.
The operational impact of CVE-2019-5458 extends beyond simple script execution, as it enables attackers to establish persistent footholds within victim environments through session hijacking and credential theft. The vulnerability is particularly dangerous because it requires minimal privileges for exploitation - attackers only need access to the server's file system to inject malicious content, making it a significant concern for organizations with compromised server access. This flaw can facilitate advanced persistent threats where attackers use the XSS vector to maintain long-term access, perform data exfiltration, or establish command and control channels through browser-based attack vectors.
Security mitigations for this vulnerability must address both the immediate code-level issues and broader architectural concerns. Organizations should implement comprehensive input validation and output encoding mechanisms that sanitize all user-supplied data before rendering in web contexts. The implementation of Content Security Policies should be enforced to prevent unauthorized script execution, while regular security audits should validate that all file system interactions properly escape or filter potentially malicious content. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and maps to ATT&CK technique T1059.007 for scripting, demonstrating how this vulnerability can be leveraged for persistent access and privilege escalation within compromised environments.
The remediation approach requires immediate patching of the http-file-server software to implement proper input sanitization and output encoding controls. Additionally, organizations should conduct comprehensive security assessments to identify any previously injected malicious payloads and implement network monitoring to detect potential exploitation attempts. Regular security training for administrators should emphasize the importance of file system access controls and the risks associated with compromised server environments. The vulnerability demonstrates the critical importance of input validation in web applications and the potential for file system compromises to translate into browser-based attack vectors, making it a prime example of how seemingly isolated security flaws can create significant operational risks.