CVE-2018-11091 in MyProcureNet
Summary
by MITRE
An issue was discovered in MyBiz MyProcureNet 5.0.0. A malicious file can be uploaded to the webserver by an attacker. It is possible for an attacker to upload a script to issue operating system commands. This vulnerability occurs because an attacker is able to adjust the "HiddenFieldControlCustomWhiteListedExtensions" parameter and add arbitrary extensions to the whitelist during the upload. For instance, if the extension .asp is added to the "HiddenFieldControlCustomWhiteListedExtensions" parameter, the server accepts "secctest.asp" as a legitimate file. Hence malicious files can be uploaded in order to execute arbitrary commands to take over the server.
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Analysis
by VulDB Data Team • 05/30/2026
This vulnerability exists in MyBiz MyProcureNet version 5.0.0 and represents a critical file upload security flaw that enables remote code execution. The issue stems from improper input validation and insufficient file extension filtering mechanisms within the application's upload functionality. Attackers can manipulate the system by modifying the "HiddenFieldControlCustomWhiteListedExtensions" parameter to include malicious file extensions, effectively bypassing the intended security controls that should prevent execution of harmful scripts on the web server. This vulnerability directly maps to CWE-434, which describes insecure file upload vulnerabilities where applications fail to properly validate file types and extensions before accepting uploads. The flaw allows attackers to escalate privileges and gain full control over the affected server, making it a severe threat to system integrity and availability.
The technical exploitation of this vulnerability occurs through parameter manipulation during the file upload process. When an attacker adds extensions like .asp to the whitelist parameter, the server treats files with those extensions as legitimate, allowing malicious scripts to be stored and executed on the web server. This represents a classic case of insecure direct object reference combined with improper access control, where the application fails to validate the content and purpose of uploaded files. The vulnerability demonstrates poor input sanitization practices and highlights the dangerous consequences of allowing user-controllable parameters to influence security decisions within the application. Attackers can leverage this flaw to upload web shells or other malicious code that can execute arbitrary commands with the privileges of the web server process.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete server compromise capabilities. Once successfully exploited, an attacker can execute arbitrary commands on the target system, potentially leading to data theft, service disruption, or further lateral movement within the network. The vulnerability enables privilege escalation attacks that can result in persistent access to the compromised system, allowing attackers to maintain control over time. This type of vulnerability is particularly dangerous in enterprise environments where web applications serve critical business functions and may have access to sensitive data or internal network resources. The attack vector is relatively simple to exploit, requiring only basic web application testing knowledge and the ability to manipulate form parameters.
Organizations should implement multiple layers of defense to mitigate this vulnerability. The primary mitigation involves implementing strict file type validation and content inspection mechanisms that do not rely solely on file extension checks. Applications should employ whitelisting approaches that validate file content against known good signatures rather than relying on extension-based filtering. Additionally, file uploads should be stored in separate directories with restricted permissions and should not be executable. Implementing proper access controls and input validation for all parameters, including hidden fields, is essential. Organizations should also consider implementing web application firewalls and runtime application self-protection mechanisms to detect and prevent parameter manipulation attempts. Regular security testing and code reviews should be conducted to identify similar vulnerabilities in other applications and to ensure that security controls remain effective against evolving attack techniques. This vulnerability demonstrates the importance of following secure coding practices and the principle of least privilege in web application development.