CVE-2014-7930 in Chrome
Summary
by MITRE
Use-after-free vulnerability in core/events/TreeScopeEventContext.cpp in the DOM implementation in Blink, as used in Google Chrome before 40.0.2214.91, allows remote attackers to cause a denial of service or possibly have unspecified other impact via crafted JavaScript code that triggers improper maintenance of TreeScope data.
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Analysis
by VulDB Data Team • 03/06/2022
The vulnerability identified as CVE-2014-7930 represents a critical use-after-free condition within the Blink rendering engine's DOM implementation, specifically in the TreeScopeEventContext.cpp file. This flaw exists in Google Chrome versions prior to 40.0.2214.91 and demonstrates a fundamental memory management error that can be exploited through carefully crafted JavaScript code. The vulnerability stems from improper maintenance of TreeScope data structures during event handling operations, creating a scenario where freed memory locations are accessed after being deallocated. Such memory corruption issues are particularly dangerous as they can lead to unpredictable behavior and potentially enable arbitrary code execution. The flaw falls under the CWE-416 category of Use After Free, which is classified as a serious memory safety vulnerability that occurs when a program continues to use a pointer after the memory it points to has been freed, creating opportunities for exploitation.
The technical exploitation of this vulnerability occurs through JavaScript code that manipulates the DOM tree structure in a manner that causes the TreeScopeEventContext to maintain incorrect references to memory locations that have already been freed. When the browser processes events within the DOM, particularly during complex tree operations or event propagation, the improper cleanup of TreeScope data structures results in memory that is no longer valid being accessed. This creates a situation where attackers can craft malicious JavaScript that triggers the specific sequence of operations leading to the use-after-free condition. The vulnerability can be triggered through various DOM manipulation techniques that involve removing elements from the tree structure while event handlers are still active or pending execution. The attack vector is particularly insidious because it requires only web-based JavaScript execution, making it accessible through standard web browsing scenarios without requiring any special privileges or user interaction beyond visiting a malicious website.
The operational impact of CVE-2014-7930 extends beyond simple denial of service to potentially enable more severe consequences including arbitrary code execution and system compromise. When the use-after-free condition occurs, it can cause the browser to crash or behave unpredictably, leading to denial of service attacks against users. However, the more dangerous aspect is that such memory corruption vulnerabilities often provide attackers with opportunities to execute arbitrary code with the privileges of the browser process. The vulnerability's exploitation can potentially allow attackers to bypass security restrictions, escalate privileges, or gain access to sensitive user data. This makes it particularly concerning in enterprise environments where browser-based attacks can serve as initial access vectors for broader security breaches. The vulnerability affects all users of affected Chrome versions and represents a significant risk to web application security, as it can be exploited through standard web delivery mechanisms without requiring any special user actions beyond visiting malicious websites.
Mitigation strategies for CVE-2014-7930 primarily focus on immediate patching and updating to versions of Google Chrome that contain the necessary security fixes. Users should immediately upgrade to Chrome version 40.0.2214.91 or later, which includes the specific fixes for the TreeScopeEventContext memory management issues. Browser vendors and system administrators should implement automated update mechanisms to ensure rapid deployment of security patches across all affected systems. Additional defensive measures include implementing content security policies that limit script execution capabilities, using sandboxing techniques to isolate browser processes, and deploying web application firewalls that can detect and block malicious JavaScript patterns. The vulnerability also highlights the importance of regular security audits and code reviews focusing on memory management practices within browser engines. Organizations should consider implementing security monitoring solutions that can detect unusual browser behavior patterns that might indicate exploitation attempts. From a broader security perspective, this vulnerability underscores the critical importance of maintaining up-to-date software and implementing comprehensive patch management processes to protect against known vulnerabilities in widely used applications. The ATT&CK framework categorizes such vulnerabilities under the T1190 technique of Exploit Public-Facing Application, emphasizing the need for proper application hardening and regular security assessments.