CVE-2025-34239 in WebAccess
Summary
by MITRE • 11/06/2025
Advantech WebAccess/VPN versions prior to 1.1.5 contain a command injection vulnerability in AppManagementController.appUpgradeAction() that allows an authenticated system administrator to execute arbitrary commands as the web server user (www-data) by supplying a crafted uploaded filename.
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Analysis
by VulDB Data Team • 12/05/2025
This vulnerability exists within Advantech WebAccess/VPN software versions prior to 1.1.5 and represents a critical command injection flaw in the AppManagementController.appUpgradeAction() method. The vulnerability specifically affects authenticated system administrators who possess administrative privileges within the WebAccess/VPN environment. The flaw manifests when the application processes uploaded files during the upgrade procedure, where it fails to properly sanitize user-supplied filenames before incorporating them into system commands. This allows an attacker with administrative access to craft malicious filenames that, when processed by the application, result in arbitrary command execution with the privileges of the web server user account, which in this case is www-data.
The technical nature of this vulnerability aligns with CWE-77 and CWE-94, which respectively cover command injection and code injection flaws. These classifications indicate that the vulnerability permits an attacker to inject and execute operating system commands through improperly validated input. The attack vector requires authentication, meaning that an attacker must first obtain valid administrative credentials to exploit this vulnerability. However, once authenticated, the impact is severe as the attacker can execute commands with the privileges of the web server user, which typically has significant access to the web application's file system and potentially underlying system resources. The www-data user context provides access to web application files and may enable further escalation depending on the system configuration.
From an operational perspective, this vulnerability presents a significant risk to industrial control systems and network infrastructure managed by Advantech WebAccess/VPN. The web server user context typically has read and write access to web application directories, which may contain sensitive configuration files, user data, and system logs. An attacker could leverage this vulnerability to modify application behavior, exfiltrate sensitive data, or establish persistent access to the system. The impact extends beyond immediate command execution as it could enable attackers to perform reconnaissance activities, deploy malware, or compromise other systems within the network that are accessible through the web server. The vulnerability affects the integrity and availability of the web application and potentially the entire underlying system infrastructure.
The recommended mitigation strategy involves upgrading to Advantech WebAccess/VPN version 1.1.5 or later, which contains the necessary patches to address the command injection vulnerability. Organizations should also implement additional security controls such as input validation and sanitization for all user-supplied data, particularly filenames and file upload parameters. Network segmentation and access control measures should be enforced to limit administrative access to only necessary personnel. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other components of the industrial control system. The principle of least privilege should be applied to web server accounts, ensuring that the www-data user has minimal required permissions. Additionally, monitoring and logging of file upload activities should be implemented to detect potential exploitation attempts. This vulnerability demonstrates the importance of secure coding practices and proper input validation in web applications, particularly those handling user-supplied data in industrial environments where system integrity is paramount.