CVE-2021-28428 : Security Advisory and Response
Discover the impact of CVE-2021-28428, a file upload vulnerability in HorizontCMS allowing remote code execution (RCE). Learn about affected systems, exploitation, and mitigation steps.
HorizontCMS before 1.0.0-beta.3 is affected by a file upload vulnerability that allows attackers to upload malicious files and execute arbitrary PHP code, leading to Remote Code Execution (RCE). Despite efforts to remediate a previous similar vulnerability (CVE-2020-27387) by restricting PHP extensions, the bypass method involves uploading .htaccess and *.hello files.
Understanding CVE-2021-28428
This CVE details a file upload vulnerability in HorizontCMS that enables RCE through the upload of specific files using the Media Files functionality.
What is CVE-2021-28428?
The vulnerability in HorizontCMS allows the upload of .htaccess and *.hello files, circumventing security measures to execute unauthorized PHP code.
The Impact of CVE-2021-28428
Exploitation of this vulnerability can result in unauthorized execution of PHP code, potentially leading to a compromise of the affected system.
Technical Details of CVE-2021-28428
This section provides technical insights into the vulnerability, including its description, affected systems and versions, and the exploitation mechanism.
Vulnerability Description
The vulnerability in HorizontCMS arises from a flaw that permits the upload of .htaccess and *.hello files, enabling the execution of malicious PHP code.
Affected Systems and Versions
HorizontCMS versions before 1.0.0-beta.3 are impacted by this file upload vulnerability.
Exploitation Mechanism
Attackers can exploit this vulnerability by uploading .htaccess and *.hello files to execute unauthorized PHP code and achieve RCE.
Mitigation and Prevention
In response to CVE-2021-28428, it is crucial to take immediate steps to secure systems and implement long-term security practices.
Immediate Steps to Take
Organizations are advised to restrict file uploads, review existing uploads for malicious content, and apply relevant security patches promptly.
Long-Term Security Practices
Implement robust file upload validation, maintain strict upload permissions, conduct regular security assessments, and educate users on safe file handling practices.
Patching and Updates
Ensure that HorizontCMS is updated to version 1.0.0-beta.3 or later to mitigate the file upload vulnerability and protect against potential RCE attacks.