CVE-2019-8331 in Bootstrap
Summary
by MITRE
In Bootstrap before 4.3.1, XSS is possible in the tooltip or popover data-template attribute.
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Analysis
by VulDB Data Team • 12/03/2024
The vulnerability identified as CVE-2019-8331 represents a cross-site scripting weakness affecting Bootstrap versions prior to 4.3.1, specifically within the tooltip and popover components. This issue arises from insufficient input validation and sanitization mechanisms in how the framework processes the data-template attribute. The flaw allows malicious actors to inject arbitrary JavaScript code through carefully crafted template content, which gets executed when users interact with affected tooltip or popover elements. The vulnerability demonstrates a classic improper neutralization of input during web application development, aligning with CWE-79 which categorizes cross-site scripting flaws as one of the most prevalent web application security vulnerabilities. Attackers can exploit this weakness by manipulating the data-template attribute to include malicious scripts that execute in the context of the victim's browser session, potentially leading to session hijacking, data theft, or further exploitation of the compromised user environment.
The technical implementation of this vulnerability stems from Bootstrap's handling of user-provided template content within tooltip and popover components. When developers pass template strings through the data-template attribute, the framework fails to properly sanitize or escape special characters that could be interpreted as executable JavaScript code. This occurs because the component rendering logic does not adequately filter or encode template parameters before incorporating them into the DOM structure. The vulnerability specifically impacts the tooltip and popover plugins where developers might dynamically construct template content based on user input or external data sources, creating a vector for malicious payload injection. The attack requires minimal privileges as it operates entirely within the browser context and can be triggered simply by hovering over or interacting with affected UI elements. This type of vulnerability falls under the ATT&CK technique T1213 which describes data from information repositories, and more specifically relates to T1566 which covers credential access through social engineering techniques that can be facilitated by such client-side vulnerabilities.
The operational impact of CVE-2019-8331 extends beyond simple script execution, as it can enable more sophisticated attacks within the application's user interface. An attacker could craft malicious tooltips or popovers that redirect users to phishing sites, steal session cookies, or inject additional malicious content into the page. The vulnerability is particularly concerning because it affects widely used UI components that are often integrated into applications with varying security postures, meaning that exploitation could occur in numerous environments without proper patching. Organizations using Bootstrap versions before 4.3.1 face potential exposure to credential theft, data exfiltration, and privilege escalation attacks when users interact with compromised UI elements. The vulnerability also represents a significant risk in applications where user-generated content is displayed through tooltips or popovers, as it could enable attackers to inject malicious code that persists across user sessions. The exploitation process typically involves crafting a malicious data-template string containing script tags or other executable content that gets rendered when the tooltip or popover is triggered, making this a persistent threat that can affect multiple users within an application's user base.
Mitigation strategies for CVE-2019-8331 primarily focus on updating Bootstrap to version 4.3.1 or later, which includes proper input sanitization and escaping mechanisms for the data-template attribute. Organizations should conduct comprehensive vulnerability assessments to identify all instances where Bootstrap components are used, particularly in tooltip and popover configurations. Additionally, developers should implement strict input validation for any user-provided template content and avoid directly incorporating external data into template attributes without proper sanitization. Security teams should consider implementing content security policies that restrict script execution within the application context, providing an additional layer of protection against exploitation attempts. Regular security audits of web applications using Bootstrap should include checks for proper template attribute handling and input validation practices. The vulnerability also highlights the importance of keeping all third-party libraries up to date and implementing automated vulnerability scanning processes that can detect outdated components. Organizations should establish security guidelines that require template content validation and sanitize all user inputs before they are processed by UI components, ensuring that the application follows secure coding practices and reduces the attack surface for similar vulnerabilities.