CVE-2019-0739 in Edge
Summary
by MITRE
A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Microsoft Edge, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2019-0752, CVE-2019-0753, CVE-2019-0862.
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Analysis
by VulDB Data Team • 05/27/2020
The vulnerability identified as CVE-2019-0739 represents a critical memory corruption flaw within Microsoft Edge's scripting engine that enables remote code execution. This vulnerability specifically affects the handling of objects in memory during JavaScript execution, creating a pathway for attackers to execute arbitrary code on affected systems. The flaw exists in the Chakra scripting engine that powers Microsoft Edge's JavaScript processing capabilities, making it particularly dangerous given the widespread use of this browser. The vulnerability is distinct from related issues CVE-2019-0752, CVE-2019-0753, and CVE-2019-0862, each representing different aspects of the same underlying scripting engine vulnerability family. According to CWE-125, this vulnerability falls under improper output validation, specifically manifesting as an out-of-bounds read condition that can lead to memory corruption. The issue is classified under ATT&CK technique T1059.007 for 'Command and Scripting Interpreter: JavaScript' and T1566.001 for 'Phishing: Spearphishing Attachment', as attackers typically leverage this vulnerability through malicious web content or spearphishing campaigns.
The technical implementation of this memory corruption vulnerability occurs when the Chakra scripting engine processes certain JavaScript objects in memory without proper validation of object boundaries. When malicious JavaScript code is executed through a web page, the engine fails to properly validate memory access patterns, leading to a situation where memory can be overwritten or accessed beyond its allocated boundaries. This type of vulnerability is particularly dangerous because it allows attackers to manipulate the memory layout of the browser process, potentially leading to arbitrary code execution. The flaw typically manifests when JavaScript objects are created, modified, or destroyed in ways that cause the engine to access memory locations that are not properly validated or constrained. The vulnerability can be triggered through various JavaScript constructs including array operations, object manipulation, and memory allocation patterns that cause the engine to misbehave. Attackers can craft specific JavaScript payloads that exploit the memory corruption to gain control over the browser process and potentially escalate privileges to the system level.
The operational impact of CVE-2019-0739 is severe given Microsoft Edge's widespread adoption across enterprise and consumer environments. Organizations running affected versions of Microsoft Edge are vulnerable to remote exploitation without user interaction, making this a particularly dangerous vulnerability for targeted attacks. The vulnerability can be exploited through drive-by downloads, malicious websites, or spearphishing campaigns that deliver malicious JavaScript code. Once successfully exploited, attackers can execute code with the privileges of the Edge process, potentially leading to full system compromise. The vulnerability affects Microsoft Edge versions including those shipped with Windows 10 versions 1803, 1809, and 1903, making it a significant concern for organizations with these systems. The risk is elevated because the exploitation does not require user interaction beyond visiting a malicious website, and the attack surface includes all users who browse the internet with the vulnerable browser. This vulnerability represents a critical threat to enterprise security infrastructure, as it allows for persistent access to systems and can be used to establish backdoors or exfiltrate sensitive data.
Mitigation strategies for CVE-2019-0739 should include immediate patch deployment through Microsoft's security updates, specifically the patches released in the May 2019 security bulletin. Organizations should also implement browser hardening measures including disabling JavaScript when not required, implementing content security policies, and using browser isolation techniques. Network-level protections such as web application firewalls and intrusion detection systems can help detect exploitation attempts, while endpoint protection solutions should be configured to monitor for suspicious JavaScript execution patterns. The vulnerability aligns with ATT&CK technique T1190 for 'Exploit Public-Facing Application' and requires organizations to implement layered security approaches including network segmentation, regular security assessments, and user awareness training. Additionally, Microsoft recommends enabling the Enhanced Protection Mode in Edge, which provides additional security mitigations against such memory corruption vulnerabilities. Organizations should also consider implementing automated patch management systems to ensure rapid deployment of security updates and maintain visibility into their patching status across all endpoints. Regular security monitoring and incident response procedures should be established to detect and respond to potential exploitation attempts.