CVE-2012-4787 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 9 and 10 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to an object that (1) was not properly initialized or (2) is deleted, aka "Improper Ref Counting Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 10/17/2024
The CVE-2012-4787 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer versions 9 and 10 that fundamentally undermines memory management mechanisms within the browser's rendering engine. This vulnerability stems from improper reference counting practices that govern how Internet Explorer handles object lifecycle management in its JavaScript engine and HTML parser components. The flaw manifests when the browser encounters maliciously crafted web content that triggers the deletion of an object while maintaining references to it, creating a scenario where subsequent operations attempt to access memory that has already been freed or reallocated.
The technical exploitation of this vulnerability leverages the browser's object reference counting system which fails to properly track object usage across different execution contexts. When Internet Explorer processes malicious web content, it creates objects in memory that are subsequently marked for deletion but not immediately destroyed. Attackers can craft web pages that manipulate object references in such a way that they force the browser to access these freed memory locations, effectively creating a use-after-free condition. This condition allows attackers to execute arbitrary code with the privileges of the user running the vulnerable browser, as the memory corruption can be leveraged to overwrite critical program structures or inject malicious payloads directly into the browser's execution space.
The operational impact of this vulnerability extends beyond simple remote code execution, as it represents a fundamental flaw in how Internet Explorer manages memory resources and object lifecycles. The vulnerability affects both Internet Explorer 9 and 10, which were widely deployed across enterprise environments and consumer markets during 2012, making the attack surface exceptionally broad. Security researchers have classified this issue as a high-severity vulnerability due to its remote exploitability and the potential for privilege escalation. The attack vector requires only a user visiting a malicious website, making it particularly dangerous for phishing campaigns and drive-by download attacks. This vulnerability directly maps to CWE-416, which describes the use of memory after it has been freed, and aligns with ATT&CK technique T1203, which covers exploitation for privilege escalation through memory corruption attacks.
Mitigation strategies for CVE-2012-4787 require immediate patch deployment through Microsoft's regular security updates, as the vulnerability cannot be effectively addressed through configuration changes or network-level protections alone. Organizations should implement browser hardening measures including disabling unnecessary browser features, implementing strict content security policies, and deploying web application firewalls to filter malicious content. The vulnerability also highlights the importance of maintaining up-to-date security patches and implementing robust vulnerability management processes that can quickly respond to emerging threats. Additionally, user education regarding safe browsing practices and the dangers of visiting untrusted websites remains crucial in reducing the risk of exploitation, though this becomes less effective against sophisticated attacks that can bypass user warnings through social engineering or automated exploitation techniques.