CVE-2011-1345 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6, 7, and 8 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing an object that (1) was not properly initialized or (2) is deleted, as demonstrated by Stephen Fewer as the first of three chained vulnerabilities during a Pwn2Own competition at CanSecWest 2011, aka "Object Management Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 01/06/2025
This vulnerability represents a critical memory corruption flaw in Microsoft Internet Explorer versions 6, 7, and 8 that stems from improper object management during memory operations. The vulnerability occurs when Internet Explorer fails to correctly handle objects that are either not properly initialized or have been deleted from memory, creating exploitable conditions that allow remote code execution. The flaw manifests when the browser attempts to access memory locations containing objects that should no longer be accessible, leading to unpredictable behavior that attackers can leverage for malicious purposes. The vulnerability was particularly significant because it was demonstrated as part of a chained exploit during the prestigious Pwn2Own competition, highlighting its practical exploitability in real-world scenarios. This type of memory corruption vulnerability falls under the CWE-119 weakness category, which specifically addresses "Improper Access to Memory" and represents a fundamental failure in memory management controls that can lead to arbitrary code execution.
The technical exploitation of this vulnerability relies on the browser's object management system failing to properly track object lifecycles and memory allocation patterns. When Internet Explorer encounters objects that are either uninitialized or have been freed from memory, it does not perform adequate validation checks before attempting to access these memory locations. This creates a window where attackers can manipulate the browser's memory state to redirect execution flow or inject malicious code into the process. The vulnerability is particularly dangerous because it operates at the memory management level, allowing attackers to bypass many traditional security controls and directly manipulate the execution environment. The exploitation technique involves carefully crafting web content that triggers the specific memory access pattern, causing the browser to execute code from the corrupted memory locations. This aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1059.001 for "Command and Scripting Interpreter: Command Shell" when considering the potential for privilege escalation and lateral movement after initial exploitation.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise when exploited successfully. Attackers can leverage this vulnerability to gain unauthorized access to user systems, potentially leading to data theft, system manipulation, or further network infiltration. The fact that this vulnerability affected multiple versions of Internet Explorer means that organizations with legacy systems were particularly at risk, as the exploitation could occur through standard web browsing activities without requiring user interaction beyond visiting malicious websites. The vulnerability's demonstration at a security conference like CanSecWest 2011 indicates that it was well-understood by the security community and could be reliably exploited by threat actors. Organizations running these affected versions of Internet Explorer faced significant risk exposure, as the vulnerability could be exploited through various attack vectors including malicious websites, email attachments, or compromised web applications. The memory corruption nature of the vulnerability also means that it could potentially be used for privilege escalation attacks, allowing attackers to move from standard user privileges to administrative access.
Mitigation strategies for this vulnerability required immediate action from organizations, including deployment of Microsoft security patches and updates to affected Internet Explorer versions. The recommended approach involved upgrading to newer versions of Internet Explorer or implementing browser security controls such as enhanced protection modes and memory protection features. Organizations should have also considered implementing network-based protections including web application firewalls and content filtering solutions to prevent access to known malicious websites. Browser hardening techniques such as disabling unnecessary browser features, implementing strict security policies, and using sandboxing mechanisms could have provided additional layers of protection. The vulnerability highlighted the importance of regular security updates and patch management processes, as well as the need for organizations to maintain current knowledge of security threats affecting their systems. Security teams needed to monitor for exploitation attempts and implement incident response procedures to quickly address any successful exploitation attempts. This vulnerability reinforced industry best practices for memory safety in web browsers and contributed to the development of more robust memory management practices in subsequent browser versions, aligning with the broader security community's focus on preventing similar memory corruption vulnerabilities through improved software development practices and security testing procedures.