CVE-2012-2546 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 9 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to a deleted object, aka "Event Listener Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 04/14/2021
The vulnerability identified as CVE-2012-2546 represents a critical use-after-free flaw in Microsoft Internet Explorer 9 that enables remote code execution through malicious web content. This vulnerability specifically affects the browser's handling of event listeners within the JavaScript engine, creating a scenario where memory management errors can be exploited by attackers to gain unauthorized system access. The flaw arises from improper object lifecycle management during event handling operations, where objects are accessed after being freed from memory, creating a potential exploitation vector for remote attackers.
The technical implementation of this vulnerability stems from the browser's JavaScript engine failing to properly track object references during event listener operations. When Internet Explorer 9 processes web content containing crafted JavaScript code, it may delete certain object references while still maintaining pointers to those locations in memory. Attackers can leverage this by constructing malicious web pages that trigger the deletion of objects while simultaneously maintaining references to them, allowing for controlled memory corruption that can be exploited to execute arbitrary code with the privileges of the running browser process.
From an operational impact perspective, this vulnerability poses significant risk to enterprise environments as it enables attackers to perform remote code execution without requiring user interaction beyond visiting a malicious website. The exploitability characteristics make it particularly dangerous in targeted attacks where adversaries can craft specific web pages designed to trigger the vulnerable code path. The vulnerability affects Windows operating systems running Internet Explorer 9, with the attack surface expanding to include any user who visits compromised websites or clicks on malicious links in email or other web-based communications. Security researchers have noted that this vulnerability can be chained with other exploits to bypass modern security mitigations such as address space layout randomization and data execution prevention mechanisms.
The vulnerability aligns with CWE-416, which describes the use of freed memory condition, and maps to ATT&CK technique T1059.007 for Windows Command Shell execution. Microsoft's security advisory indicates that the vulnerability can be exploited through multiple attack vectors including malicious websites, phishing campaigns, and compromised web servers. Organizations should implement immediate mitigations including browser updates, security policy enforcement, and network-based protections to prevent exploitation attempts. The vulnerability demonstrates the importance of proper memory management in browser implementations and highlights the need for robust input validation and object lifecycle management in complex web applications. Security professionals should monitor for exploitation attempts and consider implementing additional security layers such as application whitelisting, intrusion detection systems, and web application firewalls to protect against this and similar vulnerabilities.