CVE-2018-7556 in LimeSurvey
Summary
by MITRE
LimeSurvey 2.6.x before 2.6.7, 2.7x.x before 2.73.1, and 3.x before 3.4.2 mishandles application/controller/InstallerController.php after installation, which allows remote attackers to access the configuration file.
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Analysis
by VulDB Data Team • 01/09/2020
CVE-2018-7556 represents a critical misconfiguration vulnerability in LimeSurvey versions prior to specific patch releases, where the application fails to properly secure the InstallerController.php file after installation. This flaw stems from inadequate access controls and improper file handling mechanisms that allow unauthorized remote attackers to gain access to sensitive configuration files. The vulnerability exists within the application's post-installation security model, where the system does not adequately enforce access restrictions on critical controller files that should be protected after the installation process completes.
The technical implementation of this vulnerability involves the application's failure to properly validate access requests to the InstallerController.php file, which contains sensitive information about the system configuration and database credentials. This misconfiguration creates an attack surface where remote adversaries can exploit the lack of proper authentication checks and authorization mechanisms. The flaw demonstrates characteristics consistent with CWE-284, which addresses improper access control issues, and aligns with ATT&CK technique T1213.002 for Credential Access through data from information repositories. The vulnerability specifically targets the application's configuration management and file access controls, allowing attackers to extract potentially sensitive system information that could facilitate further exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure, as the exposed configuration files may contain database connection strings, encryption keys, and other sensitive parameters that could enable attackers to escalate their privileges or compromise the entire application infrastructure. Attackers could leverage this access to perform unauthorized database queries, modify application settings, or even establish persistent access to the system. The vulnerability affects multiple major release lines of LimeSurvey, indicating a systemic issue within the application's security architecture that was not properly addressed across different version branches.
Organizations affected by this vulnerability should immediately implement mitigations including immediate patching to the specified version releases, proper file permission adjustments, and network-level access controls to restrict access to sensitive application files. The recommended remediation approach involves ensuring that installer controller files are properly secured after installation completion and that access controls are enforced through proper authentication mechanisms. Security teams should also conduct thorough audits of their LimeSurvey installations to verify that no unauthorized access has occurred and that proper access control measures have been implemented to prevent similar vulnerabilities in other application components.