CVE-2012-3975 in Firefox
Summary
by MITRE
The DOMParser component in Mozilla Firefox before 15.0, Thunderbird before 15.0, and SeaMonkey before 2.12 loads subresources during parsing of text/html data within an extension, which allows remote attackers to obtain sensitive information by providing crafted data to privileged extension code.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2012-3975 represents a critical information disclosure flaw within the DOMParser component of Mozilla Firefox and related products. This vulnerability affects versions prior to 15.0 for Firefox, 15.0 for Thunderbird, and 2.12 for SeaMonkey, creating a significant attack surface for remote threat actors seeking to exploit privileged extension code. The flaw specifically manifests when these applications process text/html data within extension contexts, enabling malicious actors to craft specially designed content that triggers unintended resource loading behaviors.
The technical mechanism behind this vulnerability involves the improper handling of subresource loading during HTML parsing operations. When privileged extension code processes text/html content, the DOMParser component inadvertently loads external resources that should remain isolated from the parsing context. This behavior creates a pathway for attackers to manipulate the parsing process and potentially access sensitive information that would normally be protected within the browser's security boundaries. The vulnerability falls under the category of information disclosure, specifically related to improper resource handling and privilege escalation within extension environments.
From an operational impact perspective, this vulnerability enables remote attackers to obtain sensitive information through crafted data injection techniques. The attack vector requires an extension with sufficient privileges to process the malicious HTML content, making it particularly dangerous in environments where browser extensions have elevated access rights. The potential information disclosure includes access to local files, network resources, and other sensitive data that should remain protected from extension code. This vulnerability directly impacts the browser's security model and could enable further attacks including data exfiltration, privilege escalation, and potential system compromise.
The vulnerability demonstrates characteristics consistent with CWE-200, which addresses information exposure, and aligns with ATT&CK techniques related to privilege escalation and information gathering. Security researchers have noted that this flaw particularly affects the browser's extension architecture, where the separation between user content and privileged extension code becomes blurred. The attack requires minimal user interaction beyond visiting a malicious website or receiving crafted email content, making it particularly dangerous in phishing scenarios. Organizations using affected versions of these browser products face significant risk of targeted attacks exploiting this information disclosure vulnerability.
Mitigation strategies for CVE-2012-3975 primarily involve immediate upgrading to patched versions of Firefox, Thunderbird, and SeaMonkey. Users should ensure they are running Firefox 15.0 or later, Thunderbird 15.0 or later, and SeaMonkey 2.12 or later to eliminate exposure to this vulnerability. Additionally, administrators should review extension permissions and implement strict extension management policies to limit the potential impact of compromised extensions. Network security controls including web proxies and content filtering solutions can provide additional protection by blocking access to known malicious domains and monitoring for suspicious resource loading patterns during HTML parsing operations.