CVE-2024-27921 in grav
Summary
by MITRE • 03/22/2024
Grav is an open-source, flat-file content management system. A file upload path traversal vulnerability has been identified in the application prior to version 1.7.45, enabling attackers to replace or create files with extensions like .json, .zip, .css, .gif, etc. This critical security flaw poses severe risks, that can allow attackers to inject arbitrary code on the server, undermine integrity of backup files by overwriting existing files or creating new ones, and exfiltrate sensitive data using CSS exfiltration techniques. Upgrading to patched version 1.7.45 can mitigate the issue.
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Analysis
by VulDB Data Team • 01/03/2025
The vulnerability identified as CVE-2024-27921 affects Grav, an open-source flat-file content management system that has gained popularity for its simplicity and flexibility in web content management. This file upload path traversal vulnerability represents a critical security flaw that undermines the fundamental integrity of the application's file handling mechanisms. The issue exists in versions prior to 1.7.45, making a significant portion of the user base potentially vulnerable to exploitation. The vulnerability stems from inadequate input validation and sanitization within the file upload functionality, creating an attack surface that allows malicious actors to manipulate file paths during the upload process. This flaw particularly impacts the system's ability to properly validate file destinations, enabling attackers to bypass intended security restrictions.
The technical implementation of this vulnerability allows attackers to exploit the path traversal mechanism through carefully crafted file uploads that can target various file extensions including .json, .zip, .css, and .gif. This capability enables adversaries to replace existing system files or create new malicious files in strategic locations within the application's directory structure. The vulnerability operates by manipulating the file upload process to traverse directories outside of the intended upload location, potentially allowing access to sensitive system files or configuration data. Attackers can leverage this weakness to overwrite critical backup files, inject malicious code, or establish persistent access points within the compromised environment. The path traversal aspect of the vulnerability specifically relates to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal attacks.
The operational impact of this vulnerability extends far beyond simple file manipulation, as it provides attackers with multiple attack vectors for compromising the target system. The ability to inject arbitrary code through file uploads creates opportunities for remote code execution, which can lead to complete system compromise and unauthorized access to sensitive data. Backup file integrity is particularly at risk as attackers can overwrite existing backups with malicious content, potentially corrupting recovery mechanisms and making system restoration more difficult. The CSS exfiltration techniques mentioned in the vulnerability description represent a sophisticated approach to data exfiltration, where attackers can leverage the application's CSS handling capabilities to extract sensitive information from the system. This approach aligns with techniques described in the ATT&CK framework under data exfiltration tactics, where adversaries use legitimate application features to bypass security controls.
The security implications of this vulnerability are severe and multi-layered, affecting not only the immediate application but potentially the entire hosting environment. When attackers can manipulate file uploads to create or replace system files, they gain opportunities to establish persistent backdoors, modify application logic, or compromise the integrity of the entire content management system. The vulnerability's impact is particularly concerning in environments where Grav is used for managing sensitive content or where the application has elevated privileges on the hosting system. Organizations using affected versions of Grav should immediately implement mitigation strategies including updating to version 1.7.45, which contains the necessary patches to address the path traversal vulnerability. Additionally, implementing proper input validation, restricting file upload capabilities, and monitoring upload activities can provide additional layers of protection against exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date security practices and regular vulnerability assessments for open-source applications that form critical components of organizational infrastructure.