CVE-2018-0856 in Edge
Summary
by MITRE
Microsoft Edge and ChakraCore in Microsoft Windows 10 1703 and 1709 allows remote code execution, due to how the scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2018-0834, CVE-2018-0835, CVE-2018-0836, CVE-2018-0837, CVE-2018-0838, CVE-2018-0840, CVE-2018-0857, CVE-2018-0858, CVE-2018-0859, CVE-2018-0860, CVE-2018-0861, and CVE-2018-0866.
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Analysis
by VulDB Data Team • 02/03/2021
The vulnerability identified as CVE-2018-0856 represents a critical memory corruption flaw within Microsoft Edge's ChakraCore JavaScript engine, affecting Windows 10 versions 1703 and 1709. This issue stems from improper handling of objects in memory during script execution, creating a pathway for remote code execution attacks that can be exploited by malicious actors without user interaction. The vulnerability specifically targets the scripting engine's memory management mechanisms, where objects are allocated, manipulated, and deallocated during JavaScript processing. Security researchers have classified this as a memory corruption vulnerability, which aligns with CWE-125, indicating an out-of-bounds read condition that can lead to arbitrary code execution.
The technical exploitation of this vulnerability occurs when a malicious website or document containing crafted JavaScript code is loaded in Microsoft Edge browser. The ChakraCore engine processes this code and encounters a memory corruption scenario that allows attackers to overwrite memory locations with malicious payloads. This flaw operates at the intersection of browser security and scripting engine reliability, where the engine fails to properly validate object references during memory operations. The vulnerability's impact extends beyond simple browser compromise, as successful exploitation can enable attackers to execute arbitrary code with the privileges of the current user, potentially leading to full system compromise. This type of vulnerability is particularly dangerous because it can be triggered through web browsing activities without requiring any special user actions beyond visiting a malicious site.
From an operational perspective, this vulnerability presents significant risk to organizations using affected Windows 10 versions, as it can be exploited remotely through web-based attack vectors. The attack surface includes any user interaction with web content, making it particularly concerning for enterprise environments where users frequently access external websites. The vulnerability's classification as a remote code execution flaw means that attackers can gain unauthorized access to systems without physical presence or user consent. This aligns with ATT&CK technique T1203, which describes exploitation of remote services and applications. Organizations with legacy systems running Windows 10 1703 and 1709 are particularly vulnerable, as these versions may not receive timely security updates or may have delayed patch deployment processes.
Mitigation strategies for CVE-2018-0856 should prioritize immediate patch deployment through Microsoft's security update channels, specifically addressing the ChakraCore memory handling issues. Organizations should implement network-based protections including web application firewalls and content filtering solutions that can detect and block malicious JavaScript payloads. Browser hardening measures such as disabling unnecessary JavaScript features, implementing strict content security policies, and using sandboxing technologies can provide additional defense layers. Security teams should also monitor for indicators of compromise related to this vulnerability, including unusual network traffic patterns or system behavior that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing layered security approaches to protect against sophisticated browser-based attacks. Organizations should conduct regular security assessments to identify systems running vulnerable Windows 10 versions and ensure timely remediation to prevent exploitation attempts that could lead to complete system compromise.