CVE-2018-0993 in Edge
Summary
by MITRE
A remote code execution vulnerability exists in the way that the Chakra scripting engine handles objects in memory in Microsoft Edge, aka "Chakra Scripting Engine Memory Corruption Vulnerability." This affects Microsoft Edge, ChakraCore. This CVE ID is unique from CVE-2018-0979, CVE-2018-0980, CVE-2018-0990, CVE-2018-0994, CVE-2018-0995, CVE-2018-1019.
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Analysis
by VulDB Data Team • 02/09/2021
The vulnerability described in CVE-2018-0993 represents a critical memory corruption flaw within Microsoft Edge's Chakra scripting engine, which serves as the JavaScript engine powering the browser's execution environment. This vulnerability specifically manifests when the Chakra engine processes certain objects in memory, creating conditions that can be exploited by malicious actors to execute arbitrary code remotely. The Chakra engine is responsible for interpreting and executing JavaScript code within Microsoft Edge, making this flaw particularly dangerous as it directly impacts the browser's core functionality and security boundaries.
The technical nature of this vulnerability falls under memory corruption patterns that are commonly classified as CWE-125, which represents "Out-of-bounds Read" conditions that can lead to memory corruption and arbitrary code execution. The flaw occurs during the handling of objects within the JavaScript engine's memory management system, where improper validation or boundary checking allows attackers to manipulate memory contents in ways that can be leveraged for code execution. This type of vulnerability typically arises when the engine fails to properly validate object boundaries or when memory allocation and deallocation routines contain flaws that can be triggered through crafted JavaScript code.
From an operational impact perspective, this vulnerability creates a significant risk for Microsoft Edge users who may encounter malicious websites or web applications that exploit this memory corruption flaw. Attackers can craft specifically designed web pages that, when loaded in Edge, trigger the memory corruption condition and subsequently execute malicious code with the privileges of the browser process. The remote code execution capability means that users do not need physical access to the system or any additional exploitation steps beyond visiting a compromised website. This vulnerability affects not only the targeted browser but also ChakraCore, which is Microsoft's open-source implementation of the Chakra engine used in various other applications and platforms, extending the potential attack surface.
The exploitation of this vulnerability aligns with techniques documented in the ATT&CK framework under the T1059.007 sub-technique for "JavaScript" and T1203 for "Exploitation for Client Execution." Security researchers have noted that such memory corruption vulnerabilities often require sophisticated exploitation techniques involving memory layout manipulation and precise control over execution flow. The vulnerability's classification as a remote code execution flaw makes it particularly attractive to threat actors who can leverage it for initial access, persistence, and privilege escalation within affected systems. Organizations using Microsoft Edge or applications built on ChakraCore are particularly vulnerable, as the attack vector requires no user interaction beyond visiting a malicious website.
Mitigation strategies for CVE-2018-0993 primarily focus on immediate patching and deployment of Microsoft's security updates, which address the underlying memory corruption issue in the Chakra engine. Additionally, organizations should implement browser hardening measures such as enabling sandboxing features, restricting JavaScript execution in sensitive contexts, and deploying web application firewalls to detect and block malicious payloads. The vulnerability's nature makes it particularly susceptible to exploit prevention through proper memory management practices and input validation, which are fundamental security controls that align with the principle of least privilege and defense in depth strategies recommended by NIST and other cybersecurity frameworks. Regular security assessments and monitoring for anomalous JavaScript behavior can help detect exploitation attempts, while user education about safe browsing practices remains crucial in reducing the attack surface.