CVE-2018-14716 in SEOmatic Plugin
Summary
by MITRE
A Server Side Template Injection (SSTI) was discovered in the SEOmatic plugin before 3.1.4 for Craft CMS, because requests that don't match any elements incorrectly generate the canonicalUrl, and can lead to execution of Twig code.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2018-14716 represents a critical Server Side Template Injection flaw in the SEOmatic plugin for Craft CMS affecting versions prior to 3.1.4. This vulnerability arises from improper handling of requests that do not match any existing elements within the CMS framework. The flaw specifically manifests when the system attempts to generate a canonicalUrl for such unmatched requests, creating an unintended pathway for malicious template code execution. The issue stems from the plugin's failure to properly sanitize or validate input parameters before incorporating them into template rendering processes, allowing attackers to inject arbitrary Twig template code that gets executed on the server side.
The technical exploitation of this vulnerability occurs through crafted requests that bypass normal element matching logic, causing the system to fall back to a default canonical URL generation mechanism. This fallback process incorrectly processes user-supplied input parameters, which then get interpreted as Twig template code rather than simple URL data. The vulnerability is classified as a Server Side Template Injection under CWE-94, specifically targeting the improper execution of code during template processing. This weakness enables attackers to execute arbitrary server-side code with the privileges of the web application, potentially leading to complete system compromise. The ATT&CK framework categorizes this under T1190 - Exploit Public-Facing Application, as it represents an attack vector through a publicly accessible CMS plugin component.
The operational impact of CVE-2018-14716 extends beyond simple code execution, as it provides attackers with the ability to perform arbitrary file operations, execute system commands, and potentially escalate privileges within the affected environment. The vulnerability's exploitation can result in data breaches, system infiltration, and unauthorized access to sensitive information stored within the Craft CMS environment. Organizations using affected versions of the SEOmatic plugin face significant risk of unauthorized code execution, which could lead to complete system compromise and data loss. The vulnerability is particularly dangerous because it requires no authentication to exploit, making it accessible to any attacker who can send requests to the affected web application.
Mitigation strategies for CVE-2018-14716 focus primarily on immediate patching of the affected plugin to version 3.1.4 or later, which contains the necessary fixes for proper input validation and canonical URL generation. System administrators should also implement additional protective measures including input validation at the web application firewall level, monitoring for suspicious template code patterns, and restricting access to plugin management interfaces. Organizations should conduct comprehensive security assessments of their Craft CMS installations to identify any other vulnerable plugins or components that might exhibit similar template injection vulnerabilities. The remediation process should include thorough testing of the patched version to ensure that legitimate functionality remains intact while eliminating the security risk. Additionally, implementing proper security monitoring and logging of template processing activities can help detect potential exploitation attempts and provide early warning of security incidents.