CVE-2016-9070 in Firefox
Summary
by MITRE
A maliciously crafted page loaded to the sidebar through a bookmark can reference a privileged chrome window and engage in limited JavaScript operations violating cross-origin protections. This vulnerability affects Firefox < 50.
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Analysis
by VulDB Data Team • 01/31/2018
This vulnerability represents a sophisticated cross-origin security flaw in Firefox browsers prior to version 50, specifically targeting the browser's privilege separation mechanisms. The issue arises from how Firefox handles bookmarked pages loaded into the sidebar component, creating an unexpected pathway for malicious actors to access privileged chrome windows through carefully crafted web content. The vulnerability exploits the browser's trust model by allowing a malicious page to reference and interact with privileged chrome windows, effectively bypassing standard cross-origin protection mechanisms that should normally prevent such interactions.
The technical implementation of this flaw involves the manipulation of Firefox's sidebar functionality where bookmarked pages can be loaded and subsequently gain access to privileged chrome window objects. This occurs because the browser fails to properly enforce origin-based security policies when processing sidebar content, allowing JavaScript operations within the malicious page to interact with chrome-level windows that should be restricted to privileged contexts. The vulnerability specifically targets the browser's internal chrome protocol handling and demonstrates a failure in the security boundary enforcement between user content and privileged browser components.
Operationally, this vulnerability enables attackers to perform limited but potentially dangerous JavaScript operations against privileged chrome windows, creating a significant security risk for users running affected Firefox versions. The impact extends beyond simple cross-origin violations as it allows for potential information disclosure, privilege escalation, and other malicious activities that could compromise user sessions and browser integrity. Attackers could leverage this vulnerability to execute code in privileged contexts, potentially leading to full browser compromise and user data exposure.
The vulnerability aligns with CWE-200, which addresses information exposure, and CWE-352, which covers cross-site request forgery, while also demonstrating characteristics of ATT&CK technique T1059 for command and scripting interpreter. Organizations should immediately update to Firefox 50 or later to remediate this vulnerability, as the fix addresses the core privilege separation issue in the browser's sidebar component. Additionally, users should avoid loading untrusted content into the sidebar and maintain regular browser updates to protect against similar privilege escalation vulnerabilities. The incident highlights the importance of proper security boundary enforcement in browser architectures and the critical need for continuous security auditing of privileged code paths.