CVE-2006-2787 in Firefox
Summary
by MITRE
EvalInSandbox in Mozilla Firefox and Thunderbird before 1.5.0.4 allows remote attackers to gain privileges via javascript that calls the valueOf method on objects that were created outside of the sandbox.
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Analysis
by VulDB Data Team • 06/20/2019
The vulnerability described in CVE-2006-2787 represents a critical sandbox escape flaw in Mozilla Firefox and Thunderbird versions prior to 1.5.0.4. This security issue stems from improper handling of JavaScript object manipulation within the browser's security sandbox mechanism, which is designed to isolate untrusted code execution from the underlying system. The vulnerability specifically affects the EvalInSandbox functionality that was intended to provide a secure environment for executing potentially malicious JavaScript code while maintaining system integrity.
The technical flaw manifests when JavaScript code attempts to invoke the valueOf method on objects that were originally created outside of the sandbox environment. This particular method invocation creates a pathway for privilege escalation because it allows the attacker's code to access properties and methods of objects that should be restricted to the sandboxed context. The vulnerability exploits the fact that certain JavaScript objects maintain references to their original execution context, enabling malicious code to bypass the sandbox restrictions and gain elevated privileges. This type of flaw falls under the CWE-254 category of security mechanisms that are not properly implemented or enforced, specifically relating to improper access control within sandboxed environments.
The operational impact of this vulnerability is severe as it enables remote attackers to execute arbitrary code with the privileges of the browser process. Attackers can craft malicious web pages or email content that, when loaded by an affected browser, would allow them to escape the sandbox protection and potentially access system resources, modify files, or perform other malicious activities. The vulnerability is particularly dangerous because it requires no user interaction beyond visiting a malicious website or opening a compromised email, making it a prime target for drive-by attacks. This vulnerability directly maps to the ATT&CK technique T1059.007 for command and scripting interpreter, specifically targeting the JavaScript interpreter within the browser environment.
Mitigation strategies for this vulnerability involve immediate patching of affected browser versions to 1.5.0.4 or later, which contains the necessary fixes to properly enforce sandbox boundaries. Organizations should also implement additional security measures such as disabling JavaScript when not required, using browser security extensions, and maintaining up-to-date threat intelligence to identify potential exploitation attempts. The fix implemented by Mozilla addressed the core issue by strengthening the object reference checking mechanisms within the sandbox, ensuring that objects created outside the sandbox cannot be manipulated to gain access to restricted functionality. Security teams should also consider implementing network-level protections such as web application firewalls and content filtering solutions to provide additional defense-in-depth against exploitation attempts targeting this vulnerability.