CVE-2019-9765 in Blog_mini
Summary
by MITRE
In Blog_mini 1.0, XSS exists via the author name of a comment reply in the app/main/views.py articleDetails() function, related to app/templates/_article_comments.html.
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Analysis
by VulDB Data Team • 08/01/2023
The vulnerability identified as CVE-2019-9765 represents a cross-site scripting flaw within the Blog_mini 1.0 web application that specifically affects the comment reply functionality. This issue resides in the articleDetails() function located within the app/main/views.py file and manifests through the author name field of comment replies. The vulnerability stems from insufficient input validation and output sanitization mechanisms that fail to properly escape or filter user-supplied data before rendering it within the web page context. The affected template file app/templates/_article_comments.html processes and displays comment author names without adequate security measures to prevent malicious script execution.
The technical nature of this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws where untrusted data is improperly integrated into web pages without proper validation or escaping. This weakness creates an environment where attackers can inject malicious scripts into comment author names that will execute in the context of other users' browsers when they view the affected web page. The attack vector is particularly concerning as it leverages the legitimate comment functionality of the blog application, making it more difficult to detect and prevent. The vulnerability occurs during the rendering process when user-provided author names are directly inserted into HTML output without appropriate sanitization or encoding.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it can enable attackers to execute arbitrary JavaScript code in victims' browsers. This capability allows for session hijacking, credential theft, redirection to malicious sites, and potential privilege escalation within the application. The vulnerability affects all users who view articles containing maliciously crafted comment author names, creating a widespread attack surface. Attackers can exploit this weakness by submitting comment replies with author names containing malicious script payloads that execute when other users browse the affected article pages. The persistent nature of comments means that a single malicious injection can affect multiple users over extended periods, amplifying the potential damage.
Mitigation strategies for CVE-2019-9765 should focus on implementing robust input validation and output encoding mechanisms throughout the application's data flow. The primary defense involves properly escaping user-supplied data before rendering it in HTML contexts, utilizing established libraries or built-in functions that automatically handle HTML encoding. Implementing Content Security Policy headers can provide additional protection against script execution, while regular input validation should enforce strict character set restrictions and length limits for author name fields. The application should also implement proper sanitization of all user-generated content before storage and retrieval, ensuring that any potentially malicious code is neutralized before being displayed to other users. Security testing should include comprehensive XSS vulnerability scanning of all user input points, particularly those involving comment and reply functionality. The fix should be implemented following secure coding practices as outlined in the OWASP Top Ten and NIST guidelines for preventing cross-site scripting vulnerabilities.