CVE-2007-3844 in Thunderbird
Summary
by MITRE
Mozilla Firefox 2.0.0.5, Thunderbird 2.0.0.5 and before 1.5.0.13, and SeaMonkey 1.1.3 allows remote attackers to conduct cross-site scripting (XSS) attacks with chrome privileges via an addon that inserts a (1) javascript: or (2) data: link into an about:blank document loaded by chrome via (a) the window.open function or (b) a content.location assignment, aka "Cross Context Scripting." NOTE: this issue is caused by a CVE-2007-3089 regression.
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Analysis
by VulDB Data Team • 01/13/2025
This vulnerability represents a critical cross-site scripting flaw that emerged in Mozilla Firefox, Thunderbird, and SeaMonkey products, exploiting a regression from CVE-2007-3089 that allowed attackers to execute malicious code with elevated chrome privileges. The vulnerability specifically targets the browser's handling of chrome contexts and document loading mechanisms, creating a dangerous pathway for remote attackers to bypass security restrictions. The flaw occurs when an addon injects javascript: or data: links into about:blank documents that are loaded by chrome code through either window.open function calls or content.location assignments, effectively enabling attackers to execute arbitrary code within the browser's privileged chrome context.
The technical implementation of this vulnerability leverages the browser's chrome privilege escalation capabilities, where the about:blank document loading mechanism fails to properly sanitize or validate the content being injected. When chrome code loads an about:blank document through window.open or content.location assignment, it creates an environment where javascript: and data: URI schemes can execute with full chrome privileges, bypassing the normal security boundaries between user content and privileged chrome code. This creates a dangerous condition where malicious addons can inject content that executes with elevated permissions, potentially allowing attackers to access sensitive browser functionality, manipulate the browser interface, or access protected resources that should be restricted to chrome-level code only.
The operational impact of this vulnerability is severe, as it enables attackers to conduct sophisticated cross-site scripting attacks that can compromise the entire browser environment rather than just user sessions. This vulnerability affects multiple Mozilla products including Firefox 2.0.0.5 and earlier versions, Thunderbird 2.0.0.5 and earlier versions, and SeaMonkey 1.1.3 and earlier versions, making it a widespread concern across the Mozilla ecosystem. Attackers can leverage this vulnerability to create persistent backdoors, steal sensitive information, manipulate browser behavior, or escalate privileges to gain access to system resources that should remain protected from user-level content. The cross-context nature of the vulnerability means that attackers can move between different security contexts within the browser, potentially escalating their attacks from simple XSS to more sophisticated privilege escalation attacks.
The vulnerability aligns with CWE-79 Cross-Site Scripting and follows patterns consistent with ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, demonstrating how browser-based scripting can be exploited to achieve privilege escalation. The regression from CVE-2007-3089 indicates that security improvements made in earlier versions were subsequently undermined, creating a dangerous gap in the browser's security model. Organizations using affected versions of these Mozilla products face significant risk of exploitation, as the vulnerability can be triggered through legitimate addon functionality that attackers can abuse to inject malicious code. The remediation requires updating to patched versions of the affected software, as the vulnerability stems from improper handling of chrome contexts and document loading that cannot be effectively mitigated through configuration changes or workarounds. This vulnerability highlights the importance of maintaining proper security boundaries between different privilege levels within browser architectures and demonstrates how seemingly minor regression issues can create major security vulnerabilities.