CVE-2011-2369 in Firefox
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Mozilla Firefox 4.x through 4.0.1 allows remote attackers to inject arbitrary web script or HTML via an SVG element containing an HTML-encoded entity.
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Analysis
by VulDB Data Team • 11/13/2021
The vulnerability identified as CVE-2011-2369 represents a critical cross-site scripting flaw affecting Mozilla Firefox versions 4.x through 4.0.1. This security weakness stems from insufficient input validation within Firefox's SVG (Scalable Vector Graphics) processing engine, specifically when handling HTML-encoded entities within SVG elements. The vulnerability operates by exploiting the browser's failure to properly sanitize or decode HTML entities before rendering SVG content, creating a pathway for malicious actors to execute arbitrary JavaScript code within the context of a user's browsing session.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious SVG element that contains HTML-encoded entities which, upon processing by Firefox's rendering engine, are decoded and executed as JavaScript commands. This flaw falls under the CWE-79 category of Cross-Site Scripting, specifically representing a variant where the attack vector involves SVG elements rather than traditional HTML inputs. The vulnerability demonstrates a classic case of improper input sanitization where the browser fails to distinguish between legitimate SVG content and malicious script payloads, particularly when HTML entities are involved in the SVG structure.
From an operational perspective, this vulnerability poses significant risks to users of affected Firefox versions as it enables remote code execution within the browser context without requiring user interaction beyond visiting a malicious website. The attack surface is particularly concerning because SVG elements are commonly used in web graphics and can be embedded in various web pages without raising immediate suspicion. An attacker could leverage this vulnerability to steal session cookies, perform unauthorized actions on behalf of users, redirect them to malicious sites, or even install malware on the victim's system. The impact extends beyond simple data theft to potentially compromising the entire user browsing environment, as the executed scripts operate with the privileges and permissions of the victim's browser session.
Mitigation strategies for CVE-2011-2369 should prioritize immediate patching of affected Firefox versions to the latest stable releases where the vulnerability has been addressed through improved input validation and entity decoding procedures. Organizations should implement comprehensive web application firewalls and content filtering solutions that can detect and block suspicious SVG content containing encoded entities. Browser security configurations should be hardened through the implementation of strict content security policies that limit script execution and restrict the use of potentially dangerous HTML elements. Additionally, security awareness training for users should emphasize the importance of keeping browsers updated and avoiding untrusted websites that may contain malicious SVG content. The remediation approach aligns with ATT&CK framework techniques related to defense evasion and execution, where the primary mitigation focuses on preventing the initial exploitation vector through proper input validation and browser updates.