CVE-2017-9249 in Disk
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Allen Disk 1.6 allows remote authenticated users to inject arbitrary web script or HTML persistently by uploading a crafted HTML file. The attack vector is the content of this file, and the filename must be specified in the PATH_INFO to readfile.php.
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Analysis
by VulDB Data Team • 12/07/2022
The CVE-2017-9249 vulnerability represents a critical cross-site scripting flaw in Allen Disk 1.6, a web-based file management system that exposes significant security risks to authenticated users. This vulnerability operates through a persistent XSS attack vector that allows malicious actors to inject arbitrary web scripts or HTML content into the system. The flaw specifically manifests when authenticated users upload crafted HTML files that contain malicious payloads, creating a persistent threat that can affect all users interacting with the compromised system. The vulnerability's exploitation requires the attacker to leverage the PATH_INFO parameter within the readfile.php endpoint, making it particularly insidious as it operates through legitimate file handling mechanisms that administrators might not closely monitor.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the file upload and file reading components of Allen Disk 1.6. When users upload HTML files containing malicious scripts, the system fails to properly sanitize the content before displaying it to other users. The PATH_INFO parameter manipulation allows attackers to bypass normal file access controls and inject script code directly into the file reading process. This creates a persistent XSS condition where the malicious content remains stored within the system and executes whenever other users access the affected files. The vulnerability is classified under CWE-79 as a failure to sanitize output, specifically manifesting as a persistent cross-site scripting flaw that can be exploited across multiple user sessions. The attack requires authentication but does not require privileged access, making it particularly dangerous in environments where users may have legitimate file upload permissions.
The operational impact of CVE-2017-9249 extends beyond simple script injection, as it can enable attackers to perform session hijacking, steal sensitive user data, redirect victims to malicious websites, and potentially escalate privileges within the system. The persistent nature of the vulnerability means that once a malicious file is uploaded and processed, the XSS payload continues to execute against all users who access the affected content. This creates a continuous threat that can persist even after the initial attack, as the malicious code remains embedded in the system's file structure. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, specifically web shell execution, and can be leveraged as part of broader attack chains targeting web applications. Organizations using Allen Disk 1.6 face significant risk of data exfiltration, user credential theft, and potential system compromise through this persistent XSS vulnerability.
Mitigation strategies for CVE-2017-9249 should focus on implementing comprehensive input validation, output sanitization, and secure file handling practices. Organizations must ensure that all file uploads undergo strict content validation and that HTML content is properly escaped before display. The system should enforce strict file type restrictions and implement proper sanitization of filenames and content within the PATH_INFO parameter handling. Security measures should include implementing Content Security Policies to prevent script execution, regular security audits of file handling components, and mandatory updates to the Allen Disk software to address the identified vulnerability. Additionally, network monitoring should be enhanced to detect anomalous file upload patterns and suspicious PATH_INFO parameter usage that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of secure coding practices in web applications and the necessity of regular security assessments to identify and remediate persistent XSS flaws that can compromise entire user bases through simple file upload mechanisms.