CVE-2018-0942 in Internet Explorer
Summary
by MITRE
Internet Explorer in Microsoft Windows 7 SP1, Windows Server 2008 SP2 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allow elevation of privilege, due to how Internet Explorer handles zone and integrity settings, aka "Internet Explorer Elevation of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 02/05/2021
This vulnerability represents a critical elevation of privilege flaw in Microsoft Internet Explorer affecting multiple Windows operating systems from version 7 SP1 through Windows 10 versions 1709 and corresponding server editions. The weakness stems from improper handling of zone and integrity settings within the browser's security model, creating a pathway for malicious actors to escalate their privileges from standard user level to system level access. The vulnerability specifically targets the browser's security zone enforcement mechanisms that are designed to control how different types of content are handled based on their source trust level, including local intranet, trusted sites, and internet zones. When Internet Explorer processes web content, it should enforce strict integrity checks that prevent lower-privilege content from executing with elevated permissions, but this protection mechanism fails under certain conditions.
The technical exploitation of this vulnerability occurs when malicious code attempts to leverage the browser's security zone handling to bypass integrity level restrictions. Attackers can craft web pages or deliver malicious content that exploits the improper zone enforcement, allowing code execution with higher privileges than initially intended. This flaw operates at the kernel level where security policies are enforced, making it particularly dangerous as it can enable attackers to execute arbitrary code with system-level privileges. The vulnerability is classified under CWE-276 which specifically addresses improper privilege management and inadequate access control mechanisms. According to the ATT&CK framework, this represents a privilege escalation technique that can be used to move laterally within a compromised system and establish persistent access. The exploitation typically involves a combination of browser-based attacks and local privilege escalation techniques that take advantage of the flawed security zone handling.
The operational impact of this vulnerability is severe as it provides attackers with a direct pathway to gain administrative control over affected systems. Once successfully exploited, the attacker can install malware, modify system files, access sensitive data, and potentially compromise entire network infrastructures. The widespread adoption of Internet Explorer across these operating systems means that organizations with legacy systems are particularly vulnerable, as the affected versions span multiple generations of Windows platforms. The vulnerability's exploitation can occur through various attack vectors including malicious websites, phishing emails with embedded exploits, or compromised web applications that deliver malicious content to users. Security researchers have noted that the flaw can be particularly difficult to detect as the exploitation occurs within the browser's normal operation, making it appear as legitimate user behavior rather than malicious activity. Organizations should implement immediate mitigations including browser updates, security policy adjustments, and network segmentation to protect against this vulnerability.
Mitigation strategies should focus on immediate patching of all affected systems with the relevant Microsoft security updates, as well as implementing additional security controls such as disabling Internet Explorer for untrusted content, implementing strict security zones policies, and deploying application whitelisting solutions. Network-based protections including web application firewalls and intrusion detection systems can help detect and prevent exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date security configurations and implementing defense-in-depth strategies that reduce the attack surface. Organizations should conduct comprehensive security assessments to identify all systems running affected versions of Internet Explorer and prioritize remediation efforts accordingly. Regular security monitoring and incident response procedures should be enhanced to quickly detect and respond to potential exploitation attempts. The remediation process must include not only patch deployment but also security awareness training for users to recognize potentially malicious web content and avoid visiting compromised websites.