IRONSMITHINTEL
HIGHCVSS7.5
|
Actively Exploited
|CISA KEV|CVE-2018-8373|Auth: none — unauthenticated|Reboot: required|Manual only

KB4343205: Windows Server Security Update (August 2018)

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer.

Published Aug 15, 2018 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2022-04-15 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Out-of-bounds Write (CWE-787) vulnerability in Microsoft Internet Explorer Scripting Engine. A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka "Scripting Engine Memory Corruption Vulnerability." This affects Internet Explorer 9, Internet Explorer 11, Internet Explorer 10. This CVE ID is unique from CVE-2018-8353, CVE-2018-8355, CVE-2018-8359, CVE-2018-8371, CVE-2018-8372, CVE-2018-8385, CVE-2018-8389, CVE-2018-8390. Exploitation requires remote network access, higher attack complexity, no authentication required, and user interaction required.

📧

Phishing link

→

🖼

Malicious file

🔓

Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

●IT Security
●Running internet explorer: 11, 10, 9
Fixed inKB4343205, KB4343885, KB4343887, KB4343892, KB4343897, KB4343898, KB4343900, KB4343901, KB4343909 (applies to 21 product versions)
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2022-03-25 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2022-04-15.

How to patch

Manual download

For air-gapped servers or out-of-band deployment. Microsoft Update Catalog returns every OS-version variant of this update.

↗ Microsoft Update CatalogKB4343205

Manual remediation steps

Apply the Microsoft Security Update

Microsoft has released an official security update that fixes this vulnerability.

Required KB Updates

    1
    KB4343205 — https://support.microsoft.com/help/4343205
    1
    KB4343885 — https://support.microsoft.com/help/4343885
    1
    KB4343887 — https://support.microsoft.com/help/4343887
    1
    KB4343892 — https://support.microsoft.com/help/4343892
    1
    KB4343897 — https://support.microsoft.com/help/4343897
    1
    KB4343898 — https://support.microsoft.com/help/4343898
    1
    KB4343900 — https://support.microsoft.com/help/4343900
    1
    KB4343901 — https://support.microsoft.com/help/4343901
    1
    KB4343909 — https://support.microsoft.com/help/4343909

Supersedes: KB4338814, KB4338815, KB4338818, KB4338819, KB4338825, KB4338826, KB4338829, KB4338830, KB4339093

Affected Products

    1
    Internet Explorer 10 on Windows Server 2012
    1
    Internet Explorer 11 on Windows 10 Version 1607 for 32-bit Systems
    1
    Internet Explorer 11 on Windows 10 Version 1607 for x64-based Systems
    1
    Internet Explorer 11 on Windows 10 Version 1703 for 32-bit Systems
    1
    Internet Explorer 11 on Windows 10 Version 1703 for x64-based Systems
    1
    Internet Explorer 11 on Windows 10 Version 1709 for 32-bit Systems
    1
    Internet Explorer 11 on Windows 10 Version 1709 for x64-based Systems
    1
    Internet Explorer 11 on Windows 10 Version 1803 for 32-bit Systems
    1
    Internet Explorer 11 on Windows 10 Version 1803 for x64-based Systems
    1
    Internet Explorer 11 on Windows 10 for 32-bit Systems
    1
    Internet Explorer 11 on Windows 10 for x64-based Systems
    1
    Internet Explorer 11 on Windows 7 for 32-bit Systems Service Pack 1
    1
    Internet Explorer 11 on Windows 7 for x64-based Systems Service Pack 1
    1
    Internet Explorer 11 on Windows 8.1 for 32-bit systems
    1
    Internet Explorer 11 on Windows 8.1 for x64-based systems
    1
    Internet Explorer 11 on Windows RT 8.1
    1
    Internet Explorer 11 on Windows Server 2008 R2 for x64-based Systems Service Pack 1
    1
    Internet Explorer 11 on Windows Server 2012 R2
    1
    Internet Explorer 11 on Windows Server 2016
    1
    Internet Explorer 9 on Windows Server 2008 for 32-bit Systems Service Pack 2
    1
    (…1 more product versions)

Installation Methods

Windows Update (recommended)

1
Settings → Windows Update → Check for updates
2
The security update is offered if your system is in scope
3
Restart when prompted — a reboot IS required to complete the install

Microsoft Update Catalog (manual download)

1
Open https://catalog.update.microsoft.com
2
Search for KB4343205
3
Download the package matching your OS architecture and Windows build
4
Run the .msu installer with administrator privileges
5
Restart when prompted

WSUS / SCCM / Intune

Approve KB4343205 for the affected products in your update management console.

Microsoft Download Center Links

    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343205
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343885
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343887
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343892
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343897
    1
    (…4 more)

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB4343205','KB4343885','KB4343887','KB4343892','KB4343897','KB4343898','KB4343900','KB4343901','KB4343909') }

References

    1
    Microsoft Security Response Center: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8373
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2018-8373
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8373

Discovery Credit

Elliot Cao of Trend Micro Security Research working with Trend Micro’s Zero Day Initiative (ZDI)

PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.

References

↗ CVE-2018-8373↗ MSRC Advisory↗ NVD↗ KBKB4343205