CVE-2015-7204 in Firefox
Summary
by MITRE
Mozilla Firefox before 43.0 does not properly store the properties of unboxed objects, which allows remote attackers to execute arbitrary code via crafted JavaScript variable assignments.
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Analysis
by VulDB Data Team • 07/01/2022
The vulnerability identified as CVE-2015-7204 affects Mozilla Firefox versions prior to 43.0 and represents a critical security flaw in the browser's JavaScript engine. This issue stems from improper handling of object properties within the unboxing mechanism, which is a fundamental component of JavaScript's type system. The vulnerability specifically manifests when the browser processes JavaScript variable assignments that involve unboxed objects, creating a scenario where malicious code can manipulate internal memory structures. The flaw exists in the SpiderMonkey JavaScript engine that powers Firefox, particularly in how it manages the transition between boxed and unboxed representations of JavaScript objects. Attackers can exploit this weakness by crafting specially designed JavaScript code that triggers the improper storage of object properties, ultimately leading to arbitrary code execution capabilities.
The technical nature of this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and more specifically relates to improper handling of object memory management in JavaScript engines. The flaw occurs during the execution phase when JavaScript objects undergo unboxing operations, where the browser fails to properly validate or sanitize property assignments. This improper handling creates a memory corruption scenario that can be leveraged by remote attackers to execute malicious code with the privileges of the browser user. The vulnerability is particularly dangerous because it operates at the JavaScript engine level, meaning that successful exploitation can bypass many traditional security boundaries and directly impact the underlying operating system. The attack vector requires remote code execution through web content, making it highly relevant to modern web-based threat landscapes.
The operational impact of CVE-2015-7204 is severe and far-reaching across enterprise and individual users. Organizations running affected Firefox versions face significant risk of compromise through drive-by downloads, malicious websites, and social engineering campaigns that exploit this vulnerability. The vulnerability can be triggered through standard web browsing activities, making it particularly insidious as users may not be aware they are being targeted. Security teams must consider this vulnerability as a high-priority threat requiring immediate remediation, as it provides attackers with direct execution capabilities that can lead to full system compromise. The vulnerability's exploitation does not require user interaction beyond visiting a malicious website, making it an attractive target for automated attacks and botnets. Additionally, the flaw's presence in the JavaScript engine means that successful exploitation can potentially lead to privilege escalation, data theft, and persistence mechanisms within the compromised system.
Mitigation strategies for CVE-2015-7204 focus primarily on immediate version updates to Firefox 43.0 or later, which contain the necessary patches to address the object property storage issue. Organizations should implement comprehensive patch management processes to ensure all affected systems receive updates promptly, particularly given the remote execution capabilities of this vulnerability. Browser vendors and security teams should also consider implementing additional security controls such as content security policies, sandboxing mechanisms, and web application firewalls to provide defense-in-depth against potential exploitation attempts. Regular security assessments and vulnerability scanning should include checks for this specific vulnerability to ensure complete remediation across all endpoints. The ATT&CK framework categorizes this vulnerability under T1059.007 for JavaScript and T1203 for Exploitation for Client Execution, highlighting the need for both defensive and detection capabilities. System administrators should also monitor network traffic for indicators of exploitation attempts and maintain updated threat intelligence feeds to track emerging attack patterns targeting this vulnerability.