IRONSMITHINTEL
HIGHCVSS8.8
|
Actively Exploited
|CISA KEV|CVE-2018-8414|Auth: none — unauthenticated|Reboot: required|Manual only

KB4343885: Windows Server Security Update (August 2018)

A remote code execution vulnerability exists when the Windows Shell does not properly validate file paths.

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 Improper Input Validation (CWE-20) vulnerability in Microsoft Windows. A remote code execution vulnerability exists when the Windows Shell does not properly validate file paths, aka "Windows Shell Remote Code Execution Vulnerability." This affects Windows 10 Servers, Windows 10. Exploitation requires remote network access, low 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:

●Windows Administrators
●Systems Engineers
●IT Security
●Running windows 10 1703: -; windows 10 1709: -; windows 10 1803: -; windows server 1709: -; windows server 1803: -
Fixed inKB4343885, KB4343897, KB4343909 (applies to 8 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 CatalogKB4343885

Manual remediation steps

Apply the Microsoft Security Update

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

Required KB Updates

    1
    KB4343885 — https://support.microsoft.com/help/4343885
    1
    KB4343897 — https://support.microsoft.com/help/4343897
    1
    KB4343909 — https://support.microsoft.com/help/4343909

Supersedes: KB4338819, KB4338825, KB4338826

Affected Products

    1
    Windows 10 Version 1703 for 32-bit Systems
    1
    Windows 10 Version 1703 for x64-based Systems
    1
    Windows 10 Version 1709 for 32-bit Systems
    1
    Windows 10 Version 1709 for x64-based Systems
    1
    Windows 10 Version 1803 for 32-bit Systems
    1
    Windows 10 Version 1803 for x64-based Systems
    1
    Windows Server, version 1709 (Server Core Installation)
    1
    Windows Server, version 1803 (Server Core Installation)

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 KB4343885
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 KB4343885 for the affected products in your update management console.

Microsoft Download Center Links

    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343885
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343897
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4343909

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB4343885','KB4343897','KB4343909') }

References

    1
    Microsoft Security Response Center: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8414
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2018-8414
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8414

Discovery Credit

Matt Nelson (@enigma0x3) of SpecterOps

PowerShell automationComing soon

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

References

↗ CVE-2018-8414↗ MSRC Advisory↗ NVD↗ KBKB4343885