CVE-2021-44967 in LimeSurvey
Summary
by MITRE • 02/24/2022
A Remote Code Execution (RCE) vulnerabilty exists in LimeSurvey 5.2.4 via the upload and install plugins function, which could let a remote malicious user upload an arbitrary PHP code file.
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Analysis
by VulDB Data Team • 02/20/2025
The CVE-2021-44967 vulnerability represents a critical remote code execution flaw in LimeSurvey version 5.2.4 that fundamentally undermines the application's security posture. This vulnerability specifically targets the upload and install plugins functionality, creating an attack vector that allows malicious actors to bypass normal security controls and execute arbitrary code on the affected system. The flaw exists within the application's plugin management system, where insufficient input validation and sanitization permits the upload of malicious PHP files that can be executed within the web server context.
From a technical perspective, this vulnerability stems from inadequate file type validation and improper handling of uploaded plugin archives. The system fails to properly verify the contents of uploaded files, allowing attackers to submit PHP code disguised as legitimate plugin packages. This weakness directly maps to CWE-434, which describes insecure file upload vulnerabilities where applications accept files without proper validation, and aligns with ATT&CK technique T1190, which covers exploiting vulnerabilities in software applications. The vulnerability enables attackers to upload malicious PHP payloads that execute with the privileges of the web server process, potentially leading to complete system compromise.
The operational impact of CVE-2021-44967 extends beyond simple code execution, as it provides attackers with persistent access to the target environment. Once exploited, attackers can establish backdoors, exfiltrate sensitive survey data, and potentially use the compromised server as a launchpad for further attacks within the network. The vulnerability affects organizations that rely on LimeSurvey for collecting sensitive data through surveys, making it particularly dangerous for healthcare providers, financial institutions, and government agencies handling confidential information. The remote nature of the exploit means that attackers can leverage this vulnerability from anywhere on the internet without requiring physical access to the target network.
Organizations should implement immediate mitigations including applying the vendor-provided security patches, restricting upload functionality to trusted administrators only, implementing strict file type validation, and monitoring upload directories for suspicious activity. Network segmentation and firewall rules should be configured to limit access to the LimeSurvey installation, while regular security audits should verify that no malicious files have been uploaded. The vulnerability also highlights the importance of principle of least privilege, where plugin installation capabilities should be restricted to minimal necessary users and processes. Additionally, organizations should consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts and provide additional layers of defense against similar vulnerabilities in the future.