CVE-2024-28117 in grav
Summary
by MITRE • 03/22/2024
Grav is an open-source, flat-file content management system. Prior to version 1.7.45, Grav validates accessible functions through the Utils::isDangerousFunction function, but does not impose restrictions on twig functions like twig_array_map, allowing attackers to bypass the validation and execute arbitrary commands. Twig processing of static pages can be enabled in the front matter by any administrative user allowed to create or edit pages. As the Twig processor runs unsandboxed, this behavior can be used to gain arbitrary code execution and elevate privileges on the instance. Upgrading to patched version 1.7.45 can mitigate this issue.
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Analysis
by VulDB Data Team • 01/03/2025
The vulnerability identified as CVE-2024-28117 affects Grav, an open-source flat-file content management system that has gained popularity for its simplicity and flexibility in web content management. This security flaw resides in the validation mechanisms that control function accessibility within the system's utility functions, specifically within the Utils::isDangerousFunction implementation. The vulnerability represents a critical oversight in the system's security architecture where the validation logic fails to adequately restrict access to potentially dangerous functions, particularly those related to the Twig templating engine that Grav utilizes for dynamic content rendering.
The technical flaw manifests through the insufficient validation of Twig functions, specifically allowing attackers to bypass the existing security controls by leveraging functions such as twig_array_map that are not properly restricted in the validation process. This weakness occurs because the system's validation mechanism only examines certain function patterns while neglecting to block access to specific Twig functions that can be exploited for code execution. The vulnerability is particularly dangerous because it enables privilege escalation through the manipulation of static page processing, as administrative users with permissions to create or edit pages can enable Twig processing in the front matter of their content. This configuration allows the Twig processor to execute without sandboxing, creating an environment where malicious code can be executed with the privileges of the web server process.
The operational impact of this vulnerability extends beyond simple code execution to encompass full system compromise and privilege escalation capabilities. Attackers can leverage this vulnerability to execute arbitrary commands on the affected system, potentially leading to complete system takeover, data exfiltration, or the establishment of persistent backdoors. The vulnerability affects any Grav installation running versions prior to 1.7.45, making it particularly concerning given the widespread adoption of this content management system. The attack vector requires only that an attacker possess administrative privileges to create or modify pages, which is often the case in environments where content management permissions are not properly restricted. This makes the vulnerability particularly dangerous in multi-user environments where less privileged users might have access to content creation capabilities.
The mitigation strategy for CVE-2024-28117 is straightforward yet critical for maintaining system security, requiring organizations to upgrade to Grav version 1.7.45 or later, which contains the necessary patches to address the validation bypass issue. This upgrade process should be prioritized and tested in staging environments before deployment to production systems to ensure compatibility with existing content and functionality. Organizations should also consider implementing additional security measures such as restricting administrative privileges to only trusted users, monitoring content creation and modification activities, and implementing proper access controls to prevent unauthorized users from enabling Twig processing capabilities. The vulnerability aligns with CWE-78 and CWE-94 categories related to command injection and code injection respectively, and represents a technique that could be mapped to ATT&CK tactics including privilege escalation and execution through the use of valid accounts with administrative capabilities. The remediation process should also include reviewing and updating security policies to prevent similar validation bypass vulnerabilities in other components of the system architecture.