CVE-2012-4781 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 6 through 10 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to a deleted object, aka "InjectHTMLStream Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 04/20/2021
The CVE-2012-4781 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer spanning versions 6 through 10, classified under CWE-416 as improper deallocation of memory resources. This vulnerability specifically affects the InjectHTMLStream functionality within the browser's rendering engine, creating a scenario where an attacker can manipulate memory access patterns to execute arbitrary code on vulnerable systems. The flaw occurs when Internet Explorer processes web content that triggers the deletion of an object while simultaneously allowing subsequent access to that same memory location, creating a race condition that can be exploited by malicious actors.
The technical exploitation of this vulnerability relies on crafting malicious web content that leverages the browser's HTML parsing and object management mechanisms. When Internet Explorer encounters specially crafted HTML content, it may delete an object from memory while maintaining references to that object, creating a use-after-free condition. This condition allows attackers to control the memory layout and potentially inject malicious code into the browser's memory space, bypassing standard security protections. The vulnerability demonstrates a classic memory safety issue where the browser's object lifecycle management fails to properly track object references after deletion.
From an operational perspective, this vulnerability presents a severe risk to enterprise environments as it enables remote code execution without requiring user interaction beyond visiting a malicious website. The attack surface is extensive given that Internet Explorer 6 through 10 were widely deployed across corporate networks, making organizations particularly vulnerable to targeted attacks. Security researchers have documented successful exploitation techniques that leverage the vulnerability through Internet Explorer's ActiveX controls and script execution contexts, where the attacker can manipulate the browser's memory management to achieve code execution with the privileges of the browser process.
The exploitation of CVE-2012-4781 aligns with tactics described in the MITRE ATT&CK framework under the T1059 technique for command and control through scripting, and T1068 for local privilege escalation. Organizations that continued to use unsupported versions of Internet Explorer faced heightened risk as Microsoft had ceased support for these versions, leaving systems without security updates to address memory safety issues. The vulnerability underscores the importance of proper memory management in web browsers and demonstrates how seemingly minor flaws in object lifecycle management can create significant security risks.
Mitigation strategies for CVE-2012-4781 primarily focus on immediate remediation through patching Microsoft Internet Explorer to versions that address the memory management issues. Organizations should implement browser hardening measures including disabling unnecessary ActiveX controls, implementing content security policies, and deploying web application firewalls to filter malicious content. Additionally, network segmentation and user education regarding safe browsing practices can help reduce the attack surface. The vulnerability serves as a critical reminder of the importance of maintaining up-to-date software and implementing defense-in-depth strategies to protect against memory corruption vulnerabilities that can lead to complete system compromise.