CVE-2012-0171 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 through 9 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing a deleted object, aka "SelectAll Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 03/22/2021
The vulnerability identified as CVE-2012-0171 represents a critical memory management flaw in Microsoft Internet Explorer versions 6 through 9 that enables remote code execution through improper object handling in memory. This vulnerability specifically affects the browser's implementation of the SelectAll method, which is commonly used in web applications to select text or elements within a document. The flaw stems from the browser's failure to properly validate object references after memory deallocation, creating a condition where attackers can manipulate memory pointers to execute malicious code.
The technical mechanism behind this vulnerability involves the browser's handling of JavaScript objects and their memory lifecycle. When Internet Explorer processes a SelectAll operation, it maintains references to various DOM elements and JavaScript objects in memory. The flaw occurs when these objects are deleted or garbage collected but the browser fails to properly invalidate the memory pointers or references. Attackers can exploit this by crafting malicious web pages that trigger the SelectAll functionality while simultaneously manipulating the memory state to access previously deleted objects, effectively bypassing normal security boundaries and executing arbitrary code with the privileges of the running browser process.
This vulnerability presents significant operational impact across enterprise environments where older Internet Explorer versions remain in use, particularly in legacy systems or organizations with limited upgrade capabilities. The remote execution capability means that attackers can compromise systems simply by having users visit malicious websites or click on compromised links, making it particularly dangerous for phishing campaigns and drive-by attacks. The vulnerability aligns with CWE-476 which describes NULL pointer dereferences, and maps to ATT&CK technique T1203 - Exploitation for Client Execution, demonstrating how attackers leverage browser vulnerabilities to execute malicious payloads. Organizations using affected versions of Internet Explorer face increased risk of full system compromise, as the executed code can potentially escalate privileges or establish persistence mechanisms.
Mitigation strategies for CVE-2012-0171 primarily focus on immediate remediation through Microsoft security updates and patches that address the underlying memory management issues. Organizations should prioritize upgrading to supported Internet Explorer versions or migrating to modern browser platforms that have addressed this vulnerability. Additional protective measures include implementing browser security features such as enhanced protections against memory corruption, disabling unnecessary browser features, and deploying web application firewalls to filter malicious content. Network segmentation and user education regarding suspicious website visits can provide additional layers of defense. The vulnerability demonstrates the importance of regular security updates and the risks associated with maintaining outdated browser versions in enterprise environments, as it represents a classic example of how memory safety issues can lead to complete system compromise.