CVE-2019-12739 : Exploit Details and Defense Strategies
Learn about CVE-2019-12739, a critical vulnerability in the Extract add-on for Nextcloud allowing Remote Code Execution. Find out how to mitigate and prevent exploitation.
In the Extract add-on before version 1.2.0 for Nextcloud, a vulnerability in lib/Controller/ExtractionController.php allows Remote Code Execution via shell metacharacters in a RAR filename.
Understanding CVE-2019-12739
This CVE involves a critical vulnerability in the Extract add-on for Nextcloud that can lead to Remote Code Execution.
What is CVE-2019-12739?
The vulnerability in lib/Controller/ExtractionController.php allows attackers to execute remote code by exploiting shell metacharacters in a RAR filename through the ajax/extractRar.php script.
The Impact of CVE-2019-12739
The impact of this CVE is critical, with a CVSS base score of 9.0, indicating high confidentiality, integrity, and availability impacts.
Technical Details of CVE-2019-12739
This section provides more technical insights into the vulnerability.
Vulnerability Description
The vulnerability in lib/Controller/ExtractionController.php allows Remote Code Execution through shell metacharacters in a RAR filename via the ajax/extractRar.php script.
Affected Systems and Versions
- Product: Not applicable
- Vendor: Not applicable
- Versions affected: Before version 1.2.0 of the Extract add-on for Nextcloud
Exploitation Mechanism
The vulnerability can be exploited by using shell metacharacters in a RAR filename through the ajax/extractRar.php script, specifically via the nameOfFile and directory parameters.
Mitigation and Prevention
Protecting systems from CVE-2019-12739 is crucial to prevent potential exploitation.
Immediate Steps to Take
- Update Nextcloud to version 1.2.0 or newer to mitigate the vulnerability.
- Implement strict input validation to prevent malicious inputs.
- Monitor and restrict access to the affected components.
Long-Term Security Practices
- Regularly update and patch software to address security vulnerabilities.
- Conduct security audits and penetration testing to identify and remediate weaknesses.
- Educate users and administrators about safe computing practices.
- Stay informed about security advisories and best practices.
Patching and Updates
Ensure timely installation of security patches and updates to address known vulnerabilities.