Missing CSRF token checks and improper input validation in Joomla! CMS 1.7.3 through 3.7.2 lead to an XSS vulnerability.
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Analysis
by VulDB Data Team • 01/01/2021
The vulnerability identified as CVE-2017-9934 represents a critical security flaw in Joomla's built-in security controls. The missing CSRF token checks indicate that the application fails to verify the authenticity of requests originating from legitimate users, while the improper input validation allows malicious payloads to be processed and stored without adequate sanitization. This combination creates a dangerous environment where attackers can manipulate the application's behavior through crafted requests that appear legitimate to the system's security mechanisms.
The technical implementation of this vulnerability involves the exploitation of Joomla!'s form handling and authentication mechanisms. When users interact with the CMS, particularly through administrative interfaces or user-facing forms, the application should validate that requests originate from authorized sources and that input data conforms to expected formats. However, the absence of CSRF token verification means that attackers can craft malicious requests that appear to come from authenticated users, while the insufficient input validation allows JavaScript code to be injected into form fields or other user-controllable data inputs. This dual failure creates a scenario where an attacker can inject malicious scripts that execute in the browser context of any user who views the affected content, regardless of their authentication status. The vulnerability specifically targets the application's session management and input processing components, which are fundamental to maintaining application security and user data integrity.
The operational impact of CVE-2017-9934 extends beyond simple cross-site scripting, as it can enable attackers to perform a wide range of malicious activities within the compromised Joomla versions face significant risks including data breaches, unauthorized content modification, and potential complete system compromise. The vulnerability's impact is amplified by the fact that it affects multiple versions of the CMS, meaning that a large number of websites remain exposed to exploitation. This vulnerability directly maps to CWE-352, which describes Cross-Site Request Forgery, and CWE-79, which addresses Cross-Site Scripting, demonstrating how the combination of these weaknesses creates a more severe threat vector.
Security mitigations for CVE-2017-9934 primarily focus on immediate remediation through software updates and proper configuration practices. Organizations should immediately upgrade to Joomla developers includes strengthening the CSRF token validation mechanism to ensure that all forms require proper authentication tokens before processing submissions, along with implementing more robust input filtering and sanitization routines. Additionally, administrators should implement proper web application firewalls and security monitoring solutions to detect and prevent exploitation attempts. The security community recommends that organizations conduct thorough vulnerability assessments to identify any potential exploitation that may have occurred before the patch was applied, as well as implementing proper access controls and monitoring for suspicious activities within the CMS environment. This vulnerability highlights the critical importance of maintaining up-to-date security practices and the necessity of comprehensive security testing throughout the application lifecycle. The exploitability of this vulnerability aligns with ATT&CK technique T1213, which covers Data from Information Repositories, and T1059, which covers Command and Scripting Interpreter, demonstrating how such flaws can enable broader attack chains and lateral movement within compromised environments.