CVE-2021-32682 in elFinder
Summary
by MITRE • 06/15/2021
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Several vulnerabilities affect elFinder 2.1.58. These vulnerabilities can allow an attacker to execute arbitrary code and commands on the server hosting the elFinder PHP connector, even with minimal configuration. The issues were patched in version 2.1.59. As a workaround, ensure the connector is not exposed without authentication.
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Analysis
by VulDB Data Team • 06/18/2021
The CVE-2021-32682 vulnerability represents a critical security flaw in elFinder, a widely-used open-source web-based file manager that relies on JavaScript and jQuery UI for its frontend interface. This vulnerability specifically targets the PHP connector component that enables server-side file operations, creating a significant attack surface when the system is improperly configured. The flaw affects version 2.1.58 and earlier releases, making it particularly concerning given the prevalence of this file manager in web applications and content management systems. The vulnerability's severity is amplified by the fact that it can be exploited even with minimal configuration, meaning that administrators may inadvertently expose their systems to risk without realizing it.
The technical exploitation of this vulnerability stems from insufficient input validation and sanitization within the PHP connector's handling of user-supplied data. Attackers can craft malicious requests that bypass authentication mechanisms and execute arbitrary code on the server hosting the elFinder implementation. This occurs through improper handling of file operations and command execution parameters that are passed through the web interface to the backend PHP processes. The vulnerability essentially allows for remote code execution capabilities, where malicious actors can upload files, execute system commands, and potentially gain full control over the affected server. The exploitation chain typically involves manipulating parameters that control file operations, directory traversal, and command execution within the PHP connector's processing logic.
The operational impact of CVE-2021-32682 extends far beyond simple data theft, as it provides attackers with complete system compromise capabilities. Organizations running vulnerable elFinder installations face risks including unauthorized data access, system takeover, and potential lateral movement within their network infrastructure. The vulnerability's ability to function without proper authentication makes it particularly dangerous in environments where the file manager is exposed to untrusted users or the public internet. This risk is further compounded by the fact that elFinder is commonly integrated into content management systems, web applications, and development environments where the attack surface is already extensive. The vulnerability can lead to persistent backdoor access, data exfiltration, and complete system compromise, making it a high-priority issue for security teams to address immediately.
Mitigation strategies for CVE-2021-32682 primarily focus on implementing the immediate software update to version 2.1.59, which contains the necessary patches to address the input validation and sanitization flaws. Organizations should also implement robust authentication mechanisms to ensure that the elFinder connector is never exposed without proper access controls, as recommended in the vulnerability advisory. Additional protective measures include network segmentation to isolate file manager components, implementing web application firewalls to monitor and filter malicious requests, and conducting regular security assessments of web applications that utilize elFinder. The vulnerability aligns with CWE-77 and CWE-94 categories related to command injection and code execution vulnerabilities, and can be mapped to ATT&CK techniques involving remote code execution and privilege escalation. Administrators should also consider implementing least-privilege access controls and monitoring for unusual file operations or system command execution patterns that may indicate exploitation attempts.