CVE-2011-1347 in Internet Explorer
Summary
by MITRE
Unspecified vulnerability in Microsoft Internet Explorer 8 on Windows 7 allows remote attackers to bypass Protected Mode and create arbitrary files by leveraging access to a Low integrity process, as demonstrated by Stephen Fewer as the third of three chained vulnerabilities during a Pwn2Own competition at CanSecWest 2011.
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Analysis
by VulDB Data Team • 10/19/2021
The vulnerability identified as CVE-2011-1347 represents a critical security flaw in Microsoft Internet Explorer 8 running on Windows 7 systems that fundamentally undermines the operating system's security model. This weakness specifically targets the Protected Mode implementation that was introduced to mitigate the impact of browser-based exploits by running Internet Explorer in a restricted low-integrity process environment. The vulnerability exploits a design flaw that allows malicious actors to escape the confines of this restricted environment through a sophisticated attack chain that leverages existing access to low-integrity processes. During the Pwn2Own competition at CanSecWest 2011, security researcher Stephen Fewer successfully demonstrated this three-part exploit chain that ultimately enabled complete system compromise by bypassing the core security protections that should have prevented arbitrary file creation and system manipulation.
The technical mechanism behind this vulnerability involves a sophisticated exploitation of process integrity levels within Windows operating systems, specifically targeting the security boundaries between low-integrity and high-integrity processes. When Internet Explorer operates in Protected Mode, it runs with low integrity privileges to prevent malicious code from directly modifying system files or registry entries. However, CVE-2011-1347 exploits a flaw that allows an attacker who already has access to a low-integrity process to escalate privileges and gain access to higher integrity levels. This particular vulnerability operates at the kernel level and leverages the Windows security model's handling of process integrity tokens, which are designed to enforce mandatory access controls. The exploit chain demonstrates how attackers can manipulate the Windows object manager and process creation APIs to gain elevated privileges through seemingly benign operations that should not be permitted across integrity boundaries.
The operational impact of CVE-2011-1347 is severe and far-reaching, as it completely undermines the security assumptions that users and administrators rely upon when using Internet Explorer in its Protected Mode configuration. This vulnerability effectively neutralizes one of the most important security mitigations available in Windows 7, allowing remote attackers to bypass security controls that were specifically designed to prevent privilege escalation and system compromise. The implications extend beyond simple browser exploitation, as successful exploitation can lead to complete system compromise, allowing attackers to install malware, modify system files, create backdoors, and access sensitive data without proper authorization. The vulnerability's demonstration at a major security conference like Pwn2Own validates its practical exploitability and highlights the real-world danger it poses to organizations that rely on standard security configurations. Organizations running vulnerable versions of Internet Explorer 8 on Windows 7 systems face significant risk of targeted attacks that can result in data breaches, system infiltration, and complete loss of control over affected machines.
The attack vector for CVE-2011-1347 is particularly concerning because it requires minimal initial access to be effective, making it a prime target for sophisticated attackers who can leverage it as part of a broader exploitation strategy. The vulnerability's classification aligns with CWE-264, which addresses permissions, privileges, and access controls, specifically highlighting weaknesses in integrity-based access control mechanisms. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and persistence, as attackers can use the bypassed protections to establish long-term access to compromised systems. Mitigation strategies should include immediate patching of affected systems, implementation of additional security controls such as application whitelisting, and deployment of network monitoring solutions to detect suspicious behavior patterns that may indicate exploitation attempts. Organizations should also consider implementing browser isolation techniques and restricting Internet Explorer usage to trusted environments where additional security controls can be properly enforced. The vulnerability serves as a reminder of the importance of maintaining up-to-date security patches and the critical need for layered security approaches that do not rely solely on single-point protections.