CVE-2019-1237 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 CVE ID is unique from CVE-2019-1138, CVE-2019-1217, CVE-2019-1298, CVE-2019-1300.
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Analysis
by VulDB Data Team • 08/19/2020
The vulnerability described in CVE-2019-1237 represents a critical memory corruption issue within Microsoft Edge's Chakra scripting engine that enables remote code execution. This flaw specifically manifests when the engine processes certain object handling operations in memory, creating a pathway for malicious actors to execute arbitrary code on affected systems. The vulnerability affects Microsoft Edge versions prior to the security updates released in June 2019, making it particularly dangerous given Edge's widespread use as a default browser on Windows operating systems. The Chakra engine serves as the JavaScript engine for Edge and is responsible for interpreting and executing web scripts, making this vulnerability particularly impactful for web-based attacks.
The technical nature of this vulnerability stems from improper memory management within the Chakra scripting engine's object handling mechanisms. When processing specific JavaScript code patterns, the engine fails to properly validate or sanitize memory operations, leading to memory corruption that can be exploited to overwrite critical memory locations. This type of vulnerability falls under CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write operations. The memory corruption occurs during the execution of JavaScript code that manipulates object references and memory allocation patterns, creating opportunities for attackers to manipulate the execution flow of the browser process.
From an operational perspective, this vulnerability presents significant risk to enterprise environments where Microsoft Edge is the primary browser or where users may encounter malicious web content. Attackers can leverage this vulnerability through drive-by downloads, malicious websites, or spear-phishing campaigns that deliver specially crafted JavaScript payloads designed to trigger the memory corruption. The remote code execution capability means that successful exploitation can result in full system compromise, allowing attackers to install malware, steal sensitive data, or establish persistent access to affected systems. The vulnerability's classification as a remote code execution flaw aligns with ATT&CK technique T1203, which covers legitimate user access to establish persistence, and T1059, covering command and scripting interpreter usage.
Mitigation strategies for CVE-2019-1237 primarily involve applying the security updates released by Microsoft as part of their monthly patch cycle. Organizations should prioritize immediate deployment of the relevant security patches to protect against exploitation attempts. Additionally, implementing browser security controls such as enabling Enhanced Protected Mode in Edge, utilizing sandboxing mechanisms, and deploying web application firewalls can provide additional layers of protection. Network administrators should consider implementing browser hardening policies that restrict JavaScript execution in sensitive environments and monitor for suspicious web traffic patterns that may indicate exploitation attempts. Security teams should also maintain active monitoring for indicators of compromise related to this vulnerability and ensure that endpoint detection and response solutions are configured to detect anomalous memory access patterns consistent with exploitation attempts.