CVE-2016-5050 in ReadyDesk
Summary
by MITRE
Unrestricted file upload vulnerability in chat/sendfile.aspx in ReadyDesk 9.1 allows remote attackers to execute arbitrary code by uploading and requesting a .aspx file.
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Analysis
by VulDB Data Team • 11/01/2024
The vulnerability identified as CVE-2016-5050 represents a critical unrestricted file upload flaw in ReadyDesk 9.1's chat/sendfile.aspx component that enables remote code execution through malicious file uploads. This vulnerability resides within the file upload functionality of the web application, specifically targeting the sendfile.aspx endpoint that handles file transmission within the chat module. The flaw stems from inadequate input validation and sanitization mechanisms that fail to properly verify file types or content, allowing attackers to bypass security restrictions and upload potentially harmful files to the server.
The technical implementation of this vulnerability involves a classic insecure file upload scenario where the application does not enforce strict file type validation or content inspection. When users upload files through the chat functionality, the system accepts .aspx files without proper verification, creating a pathway for attackers to upload web shell files or other malicious code. The vulnerability is particularly dangerous because .aspx files are executable within the IIS web server environment, meaning that when an attacker uploads a malicious .aspx file and subsequently requests it, the server executes the code with the privileges of the web application. This presents a direct pathway for arbitrary code execution, allowing threat actors to gain full control over the affected system.
From an operational impact perspective, this vulnerability creates severe security implications for organizations using ReadyDesk 9.1, as it provides attackers with persistent access to the underlying infrastructure. The remote exploitation capability means that attackers can compromise systems without requiring physical access or local credentials, making the attack surface significantly broader. The vulnerability aligns with CWE-434 which specifically addresses "Unrestricted Upload of File with Dangerous Type" and represents a clear violation of secure coding practices. This flaw directly maps to attack techniques described in the MITRE ATT&CK framework under T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, as it enables attackers to execute commands through uploaded malicious files.
The exploitation of this vulnerability requires minimal technical expertise, making it particularly dangerous in environments where security controls are insufficient. Attackers can leverage this flaw to establish persistent backdoors, exfiltrate sensitive data, or use the compromised system as a launch point for further attacks within the network. Organizations should implement immediate mitigations including strict file type validation, content inspection, and proper file extension filtering. The recommended remediation strategy involves implementing comprehensive input validation that rejects files based on both extension and content type, ensuring that only safe file types are accepted. Additionally, uploaded files should be stored in non-executable directories, and proper access controls should be implemented to prevent direct execution of uploaded content. Organizations must also consider implementing web application firewalls and regular security assessments to detect and prevent similar vulnerabilities in other components of their web applications.