CVE-2018-8491 in Internet Explorer
Summary
by MITRE
A remote code execution vulnerability exists when Internet Explorer improperly accesses objects in memory, aka "Internet Explorer Memory Corruption Vulnerability." This affects Internet Explorer 11. This CVE ID is unique from CVE-2018-8460.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability identified as CVE-2018-8491 represents a critical memory corruption flaw within Microsoft Internet Explorer 11 that enables remote code execution under specific conditions. This vulnerability stems from Internet Explorer's improper handling of object references in memory, creating opportunities for attackers to execute arbitrary code on affected systems. The flaw specifically impacts users running Internet Explorer 11 on Windows operating systems, making it particularly concerning given the browser's widespread deployment across enterprise environments. Security researchers have classified this as a memory corruption vulnerability that operates through improper object access patterns, aligning with common exploitation techniques used in modern cyber attacks. The vulnerability's remote execution capability means that attackers can leverage it through malicious web content without requiring local system access, making it especially dangerous in targeted attack scenarios.
The technical mechanism behind CVE-2018-8491 involves Internet Explorer's memory management system failing to properly validate object references during web page rendering operations. When processing certain web content, the browser's JavaScript engine or rendering components may attempt to access memory locations that have already been freed or improperly allocated, leading to memory corruption that can be exploited by malicious actors. This type of vulnerability falls under the CWE-125 Out-of-bounds Read category, where the application reads memory beyond its intended boundaries, and can also be categorized under CWE-787 Out-of-bounds Write when attackers can manipulate memory contents to execute malicious code. The exploitation typically requires the victim to visit a malicious website or open a specially crafted document that triggers the vulnerable code path within Internet Explorer's memory management subsystem.
From an operational impact perspective, CVE-2018-8491 presents significant risk to organizations relying on Internet Explorer 11 for business operations, as it can be exploited through standard web browsing activities without requiring user interaction beyond visiting compromised websites. The vulnerability's classification as a remote code execution flaw means that attackers can gain complete system control, potentially leading to data breaches, system compromise, and lateral movement within network environments. Organizations with legacy systems that cannot immediately migrate away from Internet Explorer 11 face particular risk, as this vulnerability can be leveraged for privilege escalation and persistent access. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, highlighting its potential for both initial compromise and subsequent system control.
Mitigation strategies for CVE-2018-8491 primarily focus on immediate remediation through Microsoft security updates, which address the underlying memory corruption issue in Internet Explorer 11. Organizations should prioritize applying the relevant security patches released by Microsoft as part of their patch management protocols, particularly given the vulnerability's remote execution capabilities. Additional defensive measures include implementing browser hardening techniques such as disabling unnecessary browser features, enabling enhanced security configurations, and deploying web application firewalls to filter malicious traffic. Network segmentation and monitoring solutions can help detect exploitation attempts by identifying suspicious web traffic patterns or unusual system behavior. Organizations should also consider implementing mandatory browser migration policies to transition away from Internet Explorer 11 to more modern and secure browser alternatives, as this vulnerability represents a known weakness in legacy browser architectures. Security teams should monitor threat intelligence feeds for indicators of compromise related to this vulnerability and ensure that incident response procedures include specific protocols for addressing remote code execution vulnerabilities in browser environments.