CVE-2014-7929 in Chrome
Summary
by MITRE
Use-after-free vulnerability in the HTMLScriptElement::didMoveToNewDocument function in core/html/HTMLScriptElement.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 vectors involving movement of a SCRIPT element across documents.
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Analysis
by VulDB Data Team • 03/06/2022
The CVE-2014-7929 vulnerability represents a critical use-after-free flaw within the Blink rendering engine's DOM implementation that affects Google Chrome versions prior to 40.0.2214.91. This vulnerability specifically resides in the HTMLScriptElement::didMoveToNewDocument function located in core/html/HTMLScriptElement.cpp, making it a core component of the browser's document object model handling. The flaw manifests when a SCRIPT element is moved across different documents within the browser's rendering context, creating a scenario where memory previously allocated to the script element becomes accessible after it has been freed, leading to unpredictable behavior.
The technical execution of this vulnerability involves manipulating the movement of SCRIPT elements between different document contexts, which triggers the improper memory management within the Blink engine's DOM implementation. When a script element is transferred from one document to another, the didMoveToNewDocument function fails to properly handle the memory deallocation and subsequent access patterns, creating a use-after-free condition. This type of vulnerability falls under CWE-416, which specifically addresses the use of freed memory condition, and represents a classic example of improper memory management in web browser engines. The vulnerability's exploitation potential is significant as it can be triggered through carefully crafted HTML content that manipulates script element movement across document boundaries.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable more severe consequences including arbitrary code execution or information disclosure. Remote attackers can leverage this flaw by constructing malicious web pages that force the browser to move SCRIPT elements between documents, causing the freed memory to be accessed by subsequent operations. This creates opportunities for attackers to manipulate browser memory layout, potentially leading to privilege escalation or complete browser compromise. The vulnerability's classification aligns with ATT&CK technique T1059.006 for command and scripting interpreter, as it enables attackers to execute malicious code through script element manipulation. Additionally, the flaw demonstrates the inherent risks of complex DOM manipulation in modern browsers where document transitions can create memory management edge cases.
Mitigation strategies for CVE-2014-7929 primarily focus on immediate browser updates to versions 40.0.2214.91 and later, which contain the necessary patches to address the memory management issue in the HTMLScriptElement::didMoveToNewDocument function. Organizations should implement comprehensive patch management procedures to ensure all affected Chrome installations are updated promptly. Network-level protections can include web application firewalls that detect and block suspicious script element movement patterns, though these measures are less effective than proper browser updates. Security monitoring should focus on detecting unusual DOM manipulation patterns, particularly around script element handling, as these may indicate exploitation attempts. The vulnerability highlights the importance of robust memory management in browser engines and the need for continuous security auditing of core rendering components, particularly those handling document transitions and element movement operations.