CVE-2019-11819 in OpenCms
Summary
by MITRE
Alkacon OpenCMS v10.5.4 and before is affected by CSV (aka Excel Macro) Injection in the module New User (/opencms/system/workplace/admin/accounts/user_new.jsp) via the First Name or Last Name.
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Analysis
by VulDB Data Team • 09/12/2023
The vulnerability CVE-2019-11819 represents a critical csv injection flaw in Alkacon OpenCMS versions up to and including 10.5.4, specifically within the user management module. This vulnerability exists in the New User form at /opencms/system/workplace/admin/accounts/user_new.jsp where user input fields for First Name and Last Name are susceptible to malicious CSV injection attacks. The flaw allows attackers to inject malicious code through spreadsheet formatting that can execute when the data is opened in Microsoft Excel or other spreadsheet applications. This type of vulnerability falls under CWE-1236 which specifically addresses CSV injection and related issues in data processing systems. The vulnerability is particularly dangerous because it leverages the trust users place in spreadsheet applications and can lead to arbitrary code execution on target systems.
The technical implementation of this vulnerability occurs when user-supplied data containing malicious CSV formulas is stored in the database and later exported or displayed in spreadsheet formats. When the data is opened in Excel or similar applications, the application interprets the malicious formulas as commands rather than plain text, leading to potential code execution. Attackers can craft input strings beginning with special characters like equals sign, plus, minus, or tab that Excel interprets as formula commands. For example, inputting "=cmd|' /C calc'!" in a name field could potentially execute a calculator application on the victim's system. This vulnerability operates at the intersection of data validation and output encoding, where proper sanitization of user input fails to prevent dangerous spreadsheet formula injection.
The operational impact of this vulnerability extends beyond simple data corruption or display issues, as it creates a potential vector for full system compromise. When administrators or users export user data containing malicious entries to spreadsheet formats, they inadvertently create execution opportunities for attackers. This vulnerability is particularly concerning in enterprise environments where OpenCMS is used for content management and user administration, as it could enable attackers to escalate privileges or gain unauthorized access to sensitive systems. The attack surface is broadened by the fact that this vulnerability affects user account creation functionality, which is a fundamental administrative operation. According to ATT&CK framework, this represents a technique for privilege escalation through data manipulation and could be categorized under T1059.001 for command and script injection.
Mitigation strategies for CVE-2019-11819 must address both immediate remediation and long-term architectural improvements. The primary solution involves implementing strict input validation and sanitization for all user-supplied data, particularly in fields that may be exported to spreadsheet formats. Organizations should enforce character set restrictions that prevent dangerous spreadsheet formula characters from being accepted in user input fields. Additionally, proper output encoding should be implemented when data is exported to CSV formats to prevent formula interpretation. The recommended approach includes updating to OpenCMS version 10.5.5 or later where this vulnerability has been patched, implementing web application firewalls to detect and block malicious input patterns, and conducting regular security assessments of user input handling mechanisms. Security teams should also establish monitoring procedures to detect unusual data export activities that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices and proper input sanitization in preventing data injection attacks that can escalate to full system compromise.