CVE-2012-0155 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 9 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing a deleted object, aka "VML Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 11/29/2021
The vulnerability identified as CVE-2012-0155 represents a critical memory corruption issue within Microsoft Internet Explorer 9 that stems from improper handling of objects in memory. This flaw specifically affects the Vector Markup Language (VML) processing functionality within the browser, creating a pathway for remote code execution through the manipulation of deleted objects. The vulnerability resides in the browser's memory management system where objects that should have been destroyed remain accessible in memory, allowing attackers to exploit this memory state to execute malicious code. The issue demonstrates a classic use-after-free vulnerability pattern where memory previously allocated to an object is accessed after the object has been freed, creating an opportunity for arbitrary code execution.
The technical exploitation of this vulnerability occurs when Internet Explorer processes VML content that contains maliciously crafted objects. When the browser handles these objects, it fails to properly validate the memory state of deleted objects, allowing attackers to manipulate the memory layout and execute arbitrary code with the privileges of the victim user. This vulnerability is particularly dangerous because it leverages the browser's legitimate VML processing capabilities to create an execution environment where attacker-controlled data can be interpreted as executable code. The memory corruption aspect of this vulnerability aligns with CWE-416, which describes the use of freed memory, and represents a sophisticated exploitation technique that requires careful manipulation of the browser's memory management subsystem.
The operational impact of CVE-2012-0155 extends beyond simple remote code execution to encompass a complete compromise of the affected system. Attackers can leverage this vulnerability to deploy malware, establish persistent backdoors, or escalate privileges within the victim's environment. The vulnerability affects Windows systems running Internet Explorer 9, making it particularly dangerous in enterprise environments where this browser version was commonly deployed. The remote nature of the attack means that exploitation can occur through web-based vectors without requiring user interaction beyond visiting a malicious website, making it an ideal candidate for drive-by download attacks. This vulnerability has been extensively documented in various threat intelligence reports and represents one of the significant security flaws that led to increased awareness of browser-based attack surfaces.
Mitigation strategies for CVE-2012-0155 primarily focus on immediate patch deployment and browser hardening measures. Microsoft released security updates that addressed the memory handling issues within Internet Explorer 9's VML processing components, requiring administrators to apply these patches promptly to prevent exploitation. Organizations should implement browser isolation techniques and consider disabling VML support in Internet Explorer where possible. Security professionals should also deploy intrusion detection systems that can identify exploitation attempts targeting this vulnerability, as the attack patterns often include specific memory access patterns that can be detected. The vulnerability underscores the importance of maintaining up-to-date browser security patches and implementing comprehensive security monitoring to detect and prevent exploitation of memory corruption vulnerabilities. Additionally, organizations should consider transitioning away from Internet Explorer 9 to more modern browser versions that have better memory management and security features, as this vulnerability highlights the need for robust memory safety mechanisms in browser implementations.