The vulnerability identified as CVE-2021-43421 is a critical file upload issue found in Studio-42 elFinder versions 2.0.4 to 2.1.59. This vulnerability allows a remote malicious user to upload arbitrary files by exploiting the connector.minimal.php file, which can lead to the execution of PHP code on the server. The severity score of this vulnerability is 9.8, classifying it as critical, and highlighting its potential for significant impact on affected systems.
Organizations using the affected versions of elFinder should be aware that this vulnerability poses a serious risk, as it can lead to unauthorized access and control over the server. The ease of exploitation, combined with the lack of required privileges and user interactions, makes this vulnerability particularly dangerous.
Given the potential for exploitation, organizations must prioritize patching immediately. The CVE was published on April 7, 2022, and the last modification to this CVE was made on November 21, 2024, indicating ongoing relevance and urgency.
In addition, organizations should consider implementing additional security measures such as file type restrictions and monitoring for suspicious file uploads to further mitigate risks associated with file upload vulnerabilities.
Vulnerability Details
CVE-2021-43421 allows a remote attacker to exploit a file upload vulnerability in elFinder, specifically via the connector.minimal.php file. The vulnerability affects versions 2.0.4 to 2.1.59, and is classified under CWE-434.
According to the CVSS version 3.1 metrics, this vulnerability has a base score of 9.8, indicating a critical severity level due to the high confidentiality, integrity, and availability impacts it can cause. The lack of required privileges and user interaction for exploitation further escalates the risk posed by this vulnerability.
Technical Analysis
The root cause of CVE-2021-43421 stems from inadequate validation of files uploaded through the connector.minimal.php script. Attackers can exploit this by crafting malicious file uploads that the server mistakenly processes as legitimate.
The attack vector is network-based, with low complexity, meaning that an attacker does not need advanced skills to exploit this vulnerability. No privileges are required to execute the attack, and user interaction is also not necessary, making it easier for attackers to succeed.
The impacts include a high potential for confidentiality, integrity, and availability compromise, allowing attackers to execute arbitrary PHP code on the server, potentially leading to complete system control.
Risk & Impact Analysis
Risk to organizations includes unauthorized access to sensitive data, potential for further attacks leveraging compromised systems, and damage to organizational reputation. With a CVSS score of 9.8, this vulnerability ranks among the highest in terms of risk, and organizations must act swiftly to mitigate these threats.
The urgency for remediation is critical, especially considering that this vulnerability is not currently listed in the KEV catalog, indicating that it has not yet been widely recognized in terms of active exploitation. However, organizations should not delay in applying patches to affected systems.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Studio-42 elFinder include all versions from 2.0.4 to 2.1.59. Organizations running these versions should take immediate action to patch their systems.
Mitigation & Remediation
To mitigate this vulnerability, organizations should apply available patches to upgrade to the latest version of elFinder. If immediate patching is not feasible, consider implementing workarounds such as disabling file uploads or restricting file types to minimize exposure.
Organizations can also enhance their security posture by utilizing penetration testing to identify potential weaknesses in their file upload mechanisms.
Detection Guidance
Organizations should monitor logs for unusual file upload patterns and any unauthorized access attempts. Behavioral anomalies, such as unexpected changes in file storage locations or modifications to system files, should be flagged for further investigation.
AppSecure Threat Intelligence Insight
CVE-2021-43421 represents a significant risk that many organizations may overlook. The ability for an attacker to upload arbitrary files can lead to severe breaches and extensive system compromise.
Organizations are encouraged to adopt a proactive security stance by establishing a comprehensive vulnerability management program to continuously assess and mitigate risks associated with file uploads and other potential vulnerabilities.
Additionally, engaging in regular security assessments, including penetration testing methodologies, can help organizations identify and address weaknesses before they are exploited.
Overall, the insights gained from this vulnerability highlight the importance of vigilance in maintaining secure software environments and the need for continuous improvement in security practices.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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