CVE-2010-2768 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.5.12 and 3.6.x before 3.6.9, Thunderbird before 3.0.7 and 3.1.x before 3.1.3, and SeaMonkey before 2.0.7 do not properly restrict use of the type attribute of an OBJECT element to set a document s charset, which allows remote attackers to bypass cross-site scripting (XSS) protection mechanisms via UTF-7 encoding.
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Analysis
by VulDB Data Team • 09/24/2021
This vulnerability exists in multiple Mozilla products including Firefox, Thunderbird, and SeaMonkey where the browser fails to properly validate the type attribute of OBJECT elements when setting document charset. The flaw specifically affects versions prior to Firefox 3.5.12 and 3.6.x before 3.6.9, Thunderbird before 3.0.7 and 3.1.x before 3.1.3, and SeaMonkey before 2.0.7. The vulnerability allows remote attackers to bypass cross-site scripting protection mechanisms through UTF-7 encoding techniques that exploit improper input validation.
The technical flaw stems from inadequate sanitization of the type attribute in OBJECT elements which can be manipulated to influence document character encoding. When a web page contains an OBJECT element with a specially crafted type attribute, the browser may incorrectly interpret UTF-7 encoded data as UTF-8 or other encodings, effectively bypassing the normal charset handling mechanisms that protect against XSS attacks. This occurs because the browser does not properly validate or restrict the type attribute values that can be used to alter document charset settings.
The operational impact of this vulnerability is significant as it enables attackers to execute cross-site scripting attacks against users of affected browsers. By crafting malicious OBJECT elements with UTF-7 encoded content, attackers can potentially inject malicious scripts that would normally be blocked by XSS protection mechanisms. This allows for the execution of arbitrary code in the context of the victim's browser session, potentially leading to session hijacking, data theft, or further exploitation of the victim's system. The vulnerability affects both web applications and email clients, making it particularly dangerous as it can be exploited through multiple attack vectors.
This vulnerability is classified as a CWE-79 Improper Neutralization of Input During Web Page Generation and corresponds to the ATT&CK technique T1211 Lateral Movement through Web Shell. The flaw represents a classic input validation issue where the application fails to properly sanitize user-controllable input before using it to influence document processing. Organizations should immediately update to the patched versions of their Mozilla products to mitigate this risk. Additionally, administrators should implement web application firewalls and content security policies to provide additional layers of protection against similar encoding-based attacks. The vulnerability highlights the importance of proper input validation and the need for robust charset handling mechanisms in web browsers to prevent exploitation of encoding-related security flaws.