CVE-2018-16625 in Typesetter
Summary
by MITRE
index.php/Admin/Uploaded in Typesetter 5.1 allows XSS via an SVG file with JavaScript in a SCRIPT element.
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Analysis
by VulDB Data Team • 09/15/2023
The vulnerability CVE-2018-16625 represents a cross-site scripting flaw in Typesetter version 5.1 that specifically affects the administrative file upload functionality. This issue occurs within the index.php/Admin/Uploaded endpoint where the application processes uploaded files without adequate sanitization of SVG content. The vulnerability is particularly concerning because it allows attackers to upload malicious SVG files containing embedded javascript within SCRIPT elements, bypassing typical security measures that might filter other file types. The flaw stems from insufficient input validation and output encoding practices during the file processing workflow, creating an avenue for persistent XSS attacks that can compromise user sessions and execute unauthorized commands.
The technical implementation of this vulnerability leverages the inherent capabilities of SVG files which can contain executable javascript code within SCRIPT elements. When the Typesetter application processes these files through the administrative upload interface, it fails to properly sanitize or escape the SVG content before storing or rendering it. This oversight creates a persistent XSS vector where malicious scripts can execute in the context of other users' browsers when they view the uploaded content. The vulnerability is classified under CWE-79 as improper neutralization of script-related HTML tags in a web page, which represents one of the most common and dangerous categories of web application vulnerabilities. The attack chain typically involves an authenticated administrator uploading a malicious SVG file, which then gets executed when other users access the administrative interface or view pages containing the uploaded content.
The operational impact of CVE-2018-16625 extends beyond simple script execution as it provides attackers with potential access to administrative functions and user data. Successful exploitation could enable attackers to steal session cookies, modify content, create new administrative accounts, or even escalate privileges within the application. The vulnerability affects the confidentiality, integrity, and availability of the Typesetter application, as it allows for unauthorized access to sensitive administrative functions and potential data exfiltration. Attackers can leverage this vulnerability to maintain persistent access to the compromised system and conduct further reconnaissance activities. The impact is particularly severe in environments where Typesetter is used for content management, as it can lead to complete compromise of the website and potentially the underlying server infrastructure.
Mitigation strategies for CVE-2018-16625 should focus on implementing comprehensive input validation and output encoding mechanisms for all file uploads, particularly those involving SVG content. Organizations should immediately upgrade to Typesetter versions that address this vulnerability, as the official patch resolves the insufficient sanitization of uploaded files by implementing proper content type checking and script removal from SVG files. Network defenders should implement web application firewalls that can detect and block malicious SVG uploads containing javascript content. Additionally, security configurations should include disabling the ability to upload executable content to administrative interfaces and implementing strict file type validation that rejects SVG files containing SCRIPT elements. The mitigation approach aligns with ATT&CK technique T1059.007 for scripting and T1566.002 for malicious file upload, emphasizing the need for robust input validation and privilege separation in web application security. Regular security assessments and code reviews should be conducted to prevent similar vulnerabilities in other components of the application stack.