CVE-2012-2557 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 6 through 8 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to a deleted object, aka "cloneNode Use After Free Vulnerability."
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/14/2021
The CVE-2012-2557 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer versions 6 through 8 that enables remote code execution through malicious web content. This vulnerability specifically manifests when the browser processes a crafted website that triggers improper memory management during object handling, particularly in the cloneNode functionality. The flaw occurs when Internet Explorer attempts to access memory that has already been freed, creating a scenario where malicious code can be executed with the privileges of the victim user. The vulnerability falls under the CWE-416 category of Use After Free, which is classified as a serious memory safety issue that can lead to arbitrary code execution. This particular weakness in Internet Explorer's implementation allows attackers to exploit the browser's memory management routines by crafting specific HTML content that forces the browser to perform operations on already-released memory objects. The attack vector requires a user to visit a malicious website, making it particularly dangerous in phishing campaigns or compromised web servers. According to ATT&CK framework, this vulnerability maps to T1059.001 (Command and Scripting Interpreter: PowerShell) and T1203 (Exploitation for Client Execution) as attackers can leverage the memory corruption to inject and execute malicious code within the browser context. The technical implementation involves the browser's handling of DOM elements during cloning operations, where the object reference remains valid even after the underlying memory has been deallocated, creating a window of opportunity for attackers to manipulate the freed memory location.
The operational impact of CVE-2012-2557 extends beyond simple remote code execution to encompass complete system compromise when exploited successfully. Attackers can leverage this vulnerability to gain full control of the affected system, as the use-after-free condition allows for arbitrary code execution within the context of the Internet Explorer process. The vulnerability affects all versions of Internet Explorer from 6 through 8, representing a substantial attack surface given the widespread deployment of these older browser versions in enterprise environments. When exploited, the vulnerability can lead to privilege escalation, data theft, and persistence mechanisms being established on the compromised system. The memory corruption aspect means that attackers can potentially overwrite critical system structures or inject malicious payloads that survive browser restarts. The exploitation process typically involves crafting HTML content that triggers the cloneNode operation on specific DOM elements, followed by manipulation of the freed memory to redirect execution flow. This vulnerability is particularly concerning because it affects legacy browser versions that are no longer receiving security updates from Microsoft, leaving organizations with limited remediation options. The flaw demonstrates a fundamental memory management error in Internet Explorer's implementation of DOM operations, where proper object lifecycle management fails to prevent access to deallocated memory regions. Security researchers have noted that the vulnerability can be reliably exploited across different Windows operating systems, including Windows XP, Windows Vista, and Windows 7, making it a significant threat to enterprise environments that still maintain support for older browser versions.
Mitigation strategies for CVE-2012-2557 require a multi-layered approach that addresses both immediate security concerns and long-term remediation needs. The most effective immediate solution involves disabling the vulnerable cloneNode functionality or implementing browser security policies that restrict access to potentially dangerous DOM operations. Organizations should prioritize upgrading to supported browser versions or implementing security patches where available, though the older Internet Explorer versions affected by this vulnerability have reached end-of-life status. Network-level protections such as web application firewalls and content filtering solutions can help detect and block malicious content that attempts to exploit this vulnerability. The implementation of exploit prevention mechanisms including DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) can make exploitation more difficult, though these protections are not foolproof against well-crafted attacks. Security teams should also implement user education programs to reduce the risk of visiting malicious websites, as social engineering remains a primary attack vector for this vulnerability. According to Microsoft security best practices, disabling active scripting and using restricted browser configurations can significantly reduce the risk of exploitation. Additionally, implementing strict access controls and network segmentation can limit the potential damage if a system does become compromised. The vulnerability highlights the importance of maintaining current browser versions and implementing comprehensive patch management processes, as the affected versions of Internet Explorer are no longer receiving security updates. Organizations should also consider implementing endpoint detection and response solutions to monitor for signs of exploitation attempts, as the memory corruption pattern associated with this vulnerability can be detected through behavioral analysis of system processes. The long-term solution involves migrating away from legacy browser versions and implementing modern security practices that include regular security assessments and vulnerability management programs.