CVE-2018-3755 in sexstatic
Summary
by MITRE
XSS in sexstatic <=0.6.2 causes HTML injection in directory name(s) leads to Stored XSS when malicious file is embed with <iframe> element used in directory name.
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Analysis
by VulDB Data Team • 02/11/2020
The vulnerability identified as CVE-2018-3755 represents a stored cross-site scripting flaw in the sexstatic web application version 0.6.2 and earlier. This vulnerability arises from insufficient input validation and sanitization of directory names within the application's file management system. The flaw allows attackers to inject malicious HTML content into directory names, which then gets executed when the application displays these directory names in its user interface. The vulnerability specifically manifests when a malicious file is embedded with an iframe element within a directory name, creating a persistent XSS vector that can affect multiple users who interact with the affected application.
The technical implementation of this vulnerability stems from the application's failure to properly sanitize user-supplied directory names before rendering them in web pages. When directory names contain HTML characters or script tags, the application does not adequately escape or filter these inputs, allowing malicious code to persist in the application's database or configuration files. This stored nature of the vulnerability means that once a malicious directory name is created, it remains active and executable each time the application displays that directory name, making it particularly dangerous for web applications that allow user-generated content or file organization. The use of iframe elements within directory names amplifies the impact by enabling attackers to load malicious content from external domains, potentially leading to further exploitation such as credential theft or redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple HTML injection, as it creates a persistent attack surface that can be leveraged by threat actors to compromise user sessions and exfiltrate sensitive information. Users who browse directories containing malicious names may unknowingly execute scripts that can steal cookies, session tokens, or other sensitive data from their browsers. The vulnerability affects the application's integrity and user trust, as it enables attackers to manipulate the application's user interface and potentially redirect users to phishing sites or other malicious resources. Security professionals should note that this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and may be mapped to ATT&CK technique T1059.001 for command and scripting interpreter, as the stored XSS can be used to execute malicious scripts against other users.
Mitigation strategies for CVE-2018-3755 should focus on implementing robust input validation and output encoding mechanisms throughout the application's file management components. Organizations should immediately upgrade to sexstatic version 0.6.3 or later, which contains the necessary patches to address this vulnerability. Additionally, developers should implement comprehensive sanitization of all user-supplied directory names, ensuring that HTML characters are properly escaped or removed before storage. The application should employ context-specific output encoding when displaying directory names, particularly in HTML contexts where script execution could occur. Security measures should include regular input validation testing, automated scanning for similar vulnerabilities, and implementation of content security policies to further restrict script execution within the application. System administrators should also monitor user-generated content for suspicious directory names and establish proper access controls to limit the ability of unauthorized users to create potentially malicious directory structures.