Microsoft ChakraCore Scripting Engine Remote Code Execution Vulnerability (CVE-2018-8298)
Executive & SecOps Summary
SECOPS ASSESSMENTApplications and browser environments utilizing the Microsoft ChakraCore JavaScript engine.
Attackers can execute arbitrary code with the privileges of the current user, potentially gaining full control of the host system.
Immediately apply the official security patches from Microsoft or upgrade ChakraCore to the latest secure release.
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
For developers utilizing the open-source ChakraCore repository, pull the latest secure branch and rebuild the engine using the following commands:
# Clone and build the patched version of ChakraCore
git clone https://github.com/microsoft/ChakraCore.git
cd ChakraCore
git checkout release/2.1
./build.sh --target-arch=x64 --with-icu=/usr2. Temporary Workaround & Hardening Configuration
To mitigate the risk of exploitation before patching, restrict active scripting in untrusted zones via Group Policy or Registry modifications:
# Disable Active Scripting in the Internet Zone via Registry
Set-ItemProperty -Path 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3' -Name '1400' -Value 33. Log Audit & IoC Verification Commands
Verify the version of the active Chakra engine binary on Windows endpoints to ensure the patch has been successfully applied:
# Check the file version of Chakra.dll on the system
Get-ChildItem -Path 'C:\Windows\System32\Chakra.dll' | Select-Object -Property VersionInfo | Format-ListBlock Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory, classified as a Type Confusion vulnerability (CWE-843). The root cause lies in the JIT (Just-In-Time) compiler's optimization phase, where it fails to properly verify the type of an object before performing operations on it, leading to memory corruption.
2. Exploitation Mechanics & Attack Scenario
An attacker can exploit this vulnerability by hosting a specially crafted website designed to invoke the vulnerability through Microsoft Edge or other applications embedding ChakraCore. When a user visits the malicious site, the engine processes the crafted JavaScript, triggering the type confusion. This allows the attacker to corrupt memory, bypass security mitigations (such as ASLR/DEP), and execute arbitrary shellcode within the context of the active process.
3. Infrastructure & Business Impact
As this vulnerability is listed in the CISA KEV catalog, it represents a highly reliable vector for targeted client-side attacks. Successful exploitation can lead to complete compromise of the user's workstation, enabling lateral movement within the corporate network, intellectual property theft, and unauthorized deployment of malware.
Official Vendor Advisories & References
A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability." This affects ChakraCore. This CVE ID is unique from CVE-2018-8242, CVE-2018-8283, CVE-2018-8287, CVE-2018-8288, CVE-2018-8291, CVE-2018-8296.
Frequently Asked SecOps Questions (CVE-2018-8298)
FAQQ1. How critical is CVE-2018-8298 and is it actively exploited in the wild?
CVE-2018-8298 is rated CVSS 7.5 (HIGH) with a 30-day EPSS exploitation probability of 74.7%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2018-8298?
Primary impacted vendors include microsoft across chakracore. Scope summary: All versions of Microsoft ChakraCore prior to the July 2018 security updates.
Q3. What temporary mitigations or workarounds exist for CVE-2018-8298 before patching?
[Mitigation] Immediately apply the official security patches from Microsoft or upgrade ChakraCore to the latest secure release. Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2018-8298
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