CVE-2018-16773 in EasyCMS
Summary
by MITRE
EasyCMS 1.5 allows XSS via the index.php?s=/admin/fields/update/navTabId/listfields/callbackType/closeCurrent content field.
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Analysis
by VulDB Data Team • 03/22/2020
The vulnerability identified as CVE-2018-16773 affects EasyCMS version 1.5 and represents a cross-site scripting flaw that can be exploited through a specific parameter in the application's administrative interface. This vulnerability resides within the URL structure where the application fails to properly sanitize user input before incorporating it into dynamic web content. The attack vector specifically targets the index.php endpoint with a complex parameter sequence that includes s=/admin/fields/update/navTabId/listfields/callbackType/closeCurrent content field, indicating this is a sophisticated injection point within the content management system's administrative functionality.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding mechanisms within the EasyCMS framework. When administrators or authenticated users interact with the affected interface, the system processes the callbackType parameter without sufficient sanitization measures, allowing malicious script code to be embedded and subsequently executed within the browser context of other users who access the same administrative pages. This type of vulnerability falls under the Common Weakness Enumeration category CWE-79 which specifically addresses Cross-Site Scripting flaws, where improper validation of input data leads to the execution of malicious scripts in the victim's browser.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it can enable attackers to perform a wide range of malicious activities within the compromised system. An attacker could potentially escalate privileges, manipulate administrative functions, or establish persistent backdoors through the execution of malicious scripts. The vulnerability is particularly concerning because it targets the administrative interface, which typically contains sensitive system configuration data and user management capabilities. The attack requires minimal privileges since it leverages existing administrative functionality rather than requiring additional authentication or access rights. This vulnerability aligns with ATT&CK technique T1059.007 which describes the use of scripting languages for execution, specifically targeting web-based applications where script injection can occur through parameter manipulation.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and output encoding mechanisms throughout the application's codebase. The most effective immediate solution involves sanitizing all user-provided input, particularly parameters used in dynamic content generation, before they are processed or rendered within web pages. Organizations should implement Content Security Policy headers to prevent unauthorized script execution, ensure proper encoding of all dynamic content, and conduct thorough input validation at multiple layers within the application architecture. Additionally, regular security assessments and code reviews should be conducted to identify similar patterns of insecure parameter handling. The vulnerability demonstrates the critical importance of following secure coding practices as outlined in OWASP Top Ten and other industry standards, particularly focusing on input validation and output encoding to prevent injection-based attacks that can compromise entire web applications and their underlying data integrity.