CVE-2018-20136 in Fuel
Summary
by MITRE
XSS exists in FUEL CMS 1.4.3 via the Header or Body in the Layout Variables during new-page creation, as demonstrated by the pages/edit/1?lang=english URI.
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Analysis
by VulDB Data Team • 04/21/2020
The vulnerability CVE-2018-20136 represents a cross-site scripting flaw discovered in FUEL CMS version 1.4.3 that specifically affects the layout variables functionality during page creation processes. This issue manifests when administrators or users interact with the pages/edit/1?lang=english URI endpoint, where the application fails to properly sanitize user input submitted through header or body fields within layout variables. The vulnerability stems from insufficient input validation and output encoding mechanisms within the content management system's rendering pipeline, creating an avenue for malicious actors to inject persistent script code that executes in the context of other users' browsers.
The technical exploitation of this vulnerability occurs through the manipulation of layout variables during page creation workflows where the application stores user-provided content without adequate sanitization. When the system renders pages that contain malicious scripts within header or body fields, these scripts are executed in the browser context of legitimate users who access the affected pages. The vulnerability specifically impacts the CMS's handling of user input in the administrative interface, particularly when editing existing pages or creating new content through the designated URI path. This represents a classic stored cross-site scripting vulnerability where malicious payloads are permanently stored within the application's database and executed each time the affected content is rendered.
From an operational perspective, this vulnerability poses significant risks to organizations utilizing FUEL CMS 1.4.3 as it allows attackers to execute arbitrary scripts in the browsers of authenticated users, potentially leading to session hijacking, credential theft, or further exploitation of the compromised systems. The impact extends beyond simple data theft as attackers could leverage this vulnerability to establish persistent backdoors, deface websites, or conduct phishing attacks against other users within the same CMS environment. The vulnerability affects the integrity and confidentiality of the content management system, as malicious actors can manipulate the displayed content and potentially gain elevated privileges within the CMS if proper access controls are not in place.
Organizations should immediately implement mitigations including updating to the latest version of FUEL CMS where this vulnerability has been patched, implementing proper input sanitization and output encoding mechanisms, and conducting comprehensive security reviews of all user input handling processes. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for scripting languages and T1566 for credential access through social engineering. Additional protective measures should include implementing content security policies, regular security testing, and user input validation to prevent similar vulnerabilities from emerging in other components of the CMS infrastructure.