CVE-2013-2904 in Chrome
Summary
by MITRE
Use-after-free vulnerability in the Document::finishedParsing function in core/dom/Document.cpp in Blink, as used in Google Chrome before 29.0.1547.57, allows remote attackers to cause a denial of service or possibly have unspecified other impact via an onload event that changes an IFRAME element so that its src attribute is no longer an XML document, leading to unintended garbage collection of this document.
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Analysis
by VulDB Data Team • 05/21/2021
The CVE-2013-2904 vulnerability represents a critical use-after-free flaw within the Blink rendering engine that powers Google Chrome browsers prior to version 29.0.1547.57. This vulnerability specifically targets the Document::finishedParsing function located in core/dom/Document.cpp, demonstrating how improper memory management can lead to severe security consequences. The issue arises from the browser's handling of dynamic DOM modifications during document parsing completion, creating a window where memory references become invalid while still being accessed by subsequent operations. The vulnerability is particularly concerning as it exists within the core browser engine responsible for processing web content, making it a prime target for exploitation in malicious web environments.
The technical execution of this vulnerability involves a sophisticated race condition between document parsing completion and dynamic DOM manipulation. When a web page triggers an onload event that modifies an IFRAME element, specifically changing its src attribute to reference a non-XML document, the Blink engine's garbage collection mechanism prematurely disposes of memory resources that are still referenced elsewhere in the execution flow. This use-after-free condition occurs because the Document::finishedParsing function fails to properly account for all potential references to DOM objects that may be modified during the parsing completion phase. The flaw demonstrates poor memory lifecycle management where objects are freed before all references to them are resolved, creating a scenario where subsequent memory access operations target deallocated memory regions.
From an operational perspective, this vulnerability presents multiple attack vectors and potential impacts that extend beyond simple denial of service. Attackers can leverage this flaw to potentially execute arbitrary code through memory corruption techniques, as demonstrated by the broader category of use-after-free vulnerabilities that often serve as stepping stones to more severe exploits. The vulnerability's impact is amplified by its location within the core DOM processing functionality, meaning that any web page containing malicious JavaScript code could trigger the condition. The unspecified other impacts mentioned in the description suggest that this vulnerability could potentially be weaponized for privilege escalation or remote code execution, particularly given the nature of use-after-free conditions in memory management systems. According to CWE-416, this vulnerability maps directly to use-after-free conditions, while ATT&CK framework references would classify this under T1059 for command and scripting interpreter and potentially T1068 for exploit for privilege escalation.
Mitigation strategies for CVE-2013-2904 require immediate browser updates to versions 29.0.1547.57 and later, where the Blink engine has been patched to properly manage DOM object lifecycles during parsing completion. Organizations should implement comprehensive browser update policies and maintain awareness of vulnerable versions through security advisories. The patch addresses the core issue by ensuring that document references remain valid throughout the parsing completion process, preventing premature garbage collection of objects that may still be referenced by onload handlers or other dynamic DOM modification operations. Additional defensive measures include implementing content security policies to restrict IFRAME usage, deploying web application firewalls to monitor for suspicious DOM manipulation patterns, and maintaining regular security assessments of web applications to identify potential exploitation vectors. The vulnerability highlights the importance of thorough memory management testing in browser engines and underscores the critical need for proper reference counting and object lifecycle management in complex DOM processing environments.