CVE-2017-5453 in Firefox
Summary
by MITRE
A mechanism to inject static HTML into the RSS reader preview page due to a failure to escape characters sent as URL parameters for a feed's "TITLE" element. This vulnerability allows for spoofing but no scripted content can be run. This vulnerability affects Firefox < 53.
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Analysis
by VulDB Data Team • 08/26/2024
The vulnerability identified as CVE-2017-5453 represents a classic cross-site scripting flaw that emerged in Mozilla Firefox versions prior to 53. This security weakness resides in the RSS reader functionality where the application fails to properly sanitize user-supplied input when processing the title element of RSS feeds. The flaw specifically manifests when URL parameters containing HTML content are passed to the feed's title field, creating an injection vector that bypasses normal input validation mechanisms. The vulnerability falls under the category of CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security that allows malicious content to be executed in the context of a user's browser session.
The technical implementation of this vulnerability occurs within Firefox's RSS feed parsing and rendering engine where the application directly incorporates title parameter values into HTML preview pages without appropriate escaping or sanitization. When an attacker crafts an RSS feed with a malicious title containing HTML tags, these elements are rendered directly in the browser without proper encoding, enabling attackers to inject static HTML content into the preview interface. This mechanism operates at the presentation layer rather than the execution layer, meaning that while the vulnerability allows for content spoofing and visual manipulation of the RSS reader interface, it does not permit the execution of JavaScript or other executable code. The limitation to static HTML injection prevents more severe attacks such as those involving XSS payload execution or session hijacking, but still represents a significant threat to user experience and security awareness.
The operational impact of CVE-2017-5453 extends beyond simple visual deception, as it can be leveraged for social engineering attacks where users are misled by manipulated feed titles that appear to come from legitimate sources. Attackers can craft malicious RSS feeds that display misleading information or create false urgency, potentially leading users to click on compromised links or make erroneous decisions based on manipulated content. The vulnerability affects users who rely on Firefox's built-in RSS reader functionality, particularly those who subscribe to third-party feeds or receive feeds from untrusted sources. This attack vector is particularly concerning in enterprise environments where RSS feeds are commonly used for news aggregation, security advisories, or internal communications, as it could enable attackers to compromise user trust in legitimate information sources.
Security mitigations for this vulnerability primarily involve upgrading to Firefox version 53 or later, where proper input sanitization mechanisms have been implemented to escape HTML characters in RSS feed titles. Organizations should also implement network-level controls such as RSS feed filtering and content validation to prevent malicious feeds from reaching end-user systems. The vulnerability demonstrates the importance of proper input validation and output escaping in web applications, aligning with ATT&CK technique T1059.007 for Command and Scripting Interpreter - JavaScript and T1566.001 for Phishing - Spearphishing Attachment. Additionally, this flaw highlights the need for comprehensive security testing of web application components, particularly those handling user-generated content or external data feeds, as specified in the OWASP Top Ten Project's categories related to injection flaws and cross-site scripting vulnerabilities.