CVE-2015-6042 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in the CWindow object implementation in Microsoft Internet Explorer 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Internet Explorer Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 06/20/2022
The CVE-2015-6042 vulnerability represents a critical use-after-free flaw within Microsoft Internet Explorer 11's CWindow object implementation that fundamentally compromises system security through remote code execution capabilities. This vulnerability specifically targets the browser's handling of window objects in web applications, creating a scenario where freed memory locations can be accessed and manipulated by malicious actors. The flaw occurs when Internet Explorer properly frees memory associated with a CWindow object but fails to properly invalidate references to that memory, allowing subsequent operations to access already deallocated memory regions. Such memory corruption vulnerabilities are particularly dangerous because they can be exploited to execute arbitrary code with the privileges of the victim's browser session, potentially leading to full system compromise.
The technical exploitation of this vulnerability leverages the fundamental principles of memory management and object lifecycle handling within the browser's rendering engine. When a web page creates and subsequently destroys CWindow objects, the memory management system releases these resources back to the system heap. However, the flaw exists in the browser's reference tracking mechanism where object pointers remain valid even after the underlying memory has been freed. Attackers can craft malicious web pages that manipulate the browser's object model to trigger the use-after-free condition, causing the browser to execute malicious code loaded into the freed memory space. This technique aligns with the common attack pattern described in CWE-416, which specifically addresses use-after-free vulnerabilities where memory is accessed after it has been freed by the program. The vulnerability demonstrates how improper object reference management can create persistent security weaknesses in complex software systems.
The operational impact of CVE-2015-6042 extends beyond simple denial of service scenarios to encompass full remote code execution capabilities that can be leveraged for sophisticated attacks. When successfully exploited, this vulnerability allows attackers to execute arbitrary code within the context of the Internet Explorer process, potentially enabling privilege escalation attacks, information disclosure, and persistent system compromise. The vulnerability affects Windows systems running Internet Explorer 11, making it particularly dangerous in enterprise environments where browser-based attacks are common attack vectors. The memory corruption nature of this flaw means that attackers can potentially bypass modern security mitigations such as DEP and ASLR, as the exploitation occurs within the legitimate browser process space. This vulnerability has been catalogued under the ATT&CK framework as part of the T1203 technique, which involves the exploitation of software vulnerabilities to gain access to system resources and execute malicious code.
Mitigation strategies for CVE-2015-6042 should focus on both immediate remediation and long-term security hardening measures. Microsoft addressed this vulnerability through security updates that improved memory management and object lifecycle handling within Internet Explorer 11, specifically enhancing the reference tracking mechanism to prevent use-after-free conditions. Organizations should prioritize immediate patch deployment and consider implementing browser isolation techniques to limit the potential impact of such vulnerabilities. Additional mitigations include enabling enhanced security features within Internet Explorer, such as EMET (Enhanced Mitigation Experience Toolkit), which provides additional layers of protection against memory corruption attacks. The vulnerability highlights the importance of proper memory management practices and adherence to secure coding principles, particularly in complex software systems where object lifecycles intersect with security-sensitive operations. Security teams should also implement network-based detection mechanisms to monitor for exploitation attempts and maintain comprehensive incident response procedures to address potential compromise scenarios.