CVE-2018-16516 in Flask-Admin
Summary
by MITRE
helpers.py in Flask-Admin 1.5.2 has Reflected XSS via a crafted URL.
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Analysis
by VulDB Data Team • 05/07/2023
Flask-Admin is a popular Python web framework extension that provides administrative interfaces for Flask applications. The vulnerability exists in the helpers.py file within version 1.5.2 of this package, specifically in how it handles URL parameters during reflection operations. This flaw allows attackers to inject malicious scripts into the application's response through crafted URLs that are then reflected back to users, creating a classic reflected cross-site scripting vulnerability.
The technical implementation of this vulnerability stems from improper input validation and output encoding within the Flask-Admin helper functions. When users navigate to specific URLs containing malicious payloads, the application fails to sanitize these inputs before rendering them in the response. The reflected nature of this XSS means that the malicious script is executed in the victim's browser context when they click on the crafted link or visit the malicious URL. The vulnerability is particularly concerning because it affects the administrative interface, which typically has elevated privileges and access to sensitive data within the application.
The operational impact of CVE-2018-16516 extends beyond simple script execution as it can enable attackers to hijack user sessions, steal sensitive information, perform unauthorized actions within the administrative interface, and potentially escalate privileges. Attackers can craft URLs that, when clicked by administrators or other users with access to the Flask-Admin interface, execute malicious JavaScript code in their browsers. This could lead to complete compromise of the administrative functionality, allowing unauthorized modifications to application data, configuration changes, or even complete system takeover. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and can be mapped to ATT&CK technique T1566.001 for initial access through spearphishing attachments or links.
Mitigation strategies for this vulnerability include immediate upgrading to Flask-Admin version 1.5.3 or later where the XSS flaw has been patched. Organizations should also implement proper input validation and output encoding mechanisms throughout their applications, particularly in administrative interfaces where privileged operations occur. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against reflected XSS attacks by restricting the sources from which scripts can be executed. Regular security auditing of third-party libraries and maintaining up-to-date dependencies remains crucial for preventing such vulnerabilities from being exploited in production environments.