CVE-2017-15956 in ConverTo Video Downloader
Summary
by MITRE
ConverTo Video Downloader & Converter 1.4.1 allows Arbitrary File Download via the token parameter to download.php.
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Analysis
by VulDB Data Team • 08/24/2025
The vulnerability identified as CVE-2017-15956 affects ConverTo Video Downloader & Converter version 1.4.1, representing a critical security flaw that enables unauthorized file access through improper input validation. This issue manifests within the download.php script where the token parameter fails to adequately validate user-supplied input, creating a pathway for malicious actors to manipulate the application's file retrieval functionality. The vulnerability stems from insufficient sanitization of the token parameter, which is used to authenticate and authorize file downloads within the application's architecture.
This arbitrary file download vulnerability operates by allowing attackers to specify any file path through the token parameter, bypassing normal access controls and authentication mechanisms. When the application processes the token parameter without proper validation, it treats the input as a legitimate file reference and attempts to retrieve and serve the specified file from the server's file system. The flaw essentially transforms the legitimate download functionality into a vector for unauthorized file access, potentially exposing sensitive system files, configuration data, or other resources that should remain protected from external access.
The operational impact of this vulnerability extends beyond simple file retrieval, as it can lead to comprehensive system compromise when combined with other attack vectors. An attacker could leverage this vulnerability to download critical system files such as database configuration files, application source code, or server configuration details that could reveal sensitive information about the underlying infrastructure. This exposure creates opportunities for further exploitation, including privilege escalation, data exfiltration, or the discovery of additional vulnerabilities within the application or server environment. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1071.004 for application layer protocol and T1566 for credential access through social engineering or exploitation of application vulnerabilities. The attack surface is particularly concerning as it requires no authentication to exploit, making it accessible to any remote attacker who can interact with the application's download functionality. The vulnerability's impact is amplified by the fact that it can potentially be chained with other exploits to create more sophisticated attack scenarios, including the possibility of remote code execution if the attacker can influence the content of downloadable files.
Mitigation strategies should focus on implementing robust input validation and sanitization for all user-supplied parameters, particularly those used in file system operations. The application should enforce strict path validation to ensure that the token parameter only references files within predefined, safe directories. Additionally, implementing proper access controls and authentication mechanisms for file downloads, along with logging and monitoring of file access attempts, can help detect and prevent unauthorized access attempts. The fix should also include parameterized queries and secure coding practices to prevent path traversal attacks, ensuring that any file references are properly validated against a whitelist of allowed paths. Organizations should also consider implementing network segmentation and web application firewalls to provide additional layers of protection against such vulnerabilities.