IRONSMITHINTEL
HIGHCVSS7.8
|
Actively Exploited
|CISA KEV|CVE-2019-1322|Auth: low — authenticated user|Reboot: required|Manual only

KB4517389: Windows Server Security Update (October 2019)

A privilege escalation vulnerability exists when Windows improperly handles authentication requests. An attacker who successfully exploited this vulnerability could run processes in an elevated context.

Published Oct 10, 2019 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A local attacker, with a low-privilege account, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. CISA has confirmed use of this vulnerability in known ransomware campaigns — treat as high priority for remediation. Federal agencies are required to remediate by 2022-04-05 under CISA BOD 22-01.

How the attack worksNo clicks needed

This vulnerability affects Microsoft Windows. An elevation of privilege vulnerability exists when Windows improperly handles authentication requests, aka 'Microsoft Windows Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-1320, CVE-2019-1340. Exploitation requires local access, low attack complexity, a low-privilege authenticated account, and no user interaction required.

Am I affected?Quick check

Probably yes if any of these apply:

●Windows Administrators
●Systems Engineers
●IT Security
●Running windows 10 1803: -; windows 10 1809: -; windows 10 1903: -; windows server 1803: -; windows server 1903: -; windows server 2019: -
Fixed inKB4517389, KB4519338, KB4520008 (applies to 13 product versions)
Real-world incidentsWhat we've seen

Used in known ransomware campaigns. Threat-research write-up: http://packetstormsecurity.com/files/155723/Microsoft-UPnP-Local-Privilege-Elevation.html

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 CatalogKB4517389

Manual remediation steps

Apply the Microsoft Security Update

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

Required KB Updates

    1
    KB4517389 — https://support.microsoft.com/help/4517389
    1
    KB4519338 — https://support.microsoft.com/help/4519338
    1
    KB4520008 — https://support.microsoft.com/help/4520008

Supersedes: KB4524147, KB4524148, KB4524149

Affected Products

    1
    Windows 10 Version 1803 for 32-bit Systems
    1
    Windows 10 Version 1803 for ARM64-based Systems
    1
    Windows 10 Version 1803 for x64-based Systems
    1
    Windows 10 Version 1809 for 32-bit Systems
    1
    Windows 10 Version 1809 for ARM64-based Systems
    1
    Windows 10 Version 1809 for x64-based Systems
    1
    Windows 10 Version 1903 for 32-bit Systems
    1
    Windows 10 Version 1903 for ARM64-based Systems
    1
    Windows 10 Version 1903 for x64-based Systems
    1
    Windows Server 2019
    1
    Windows Server 2019 (Server Core installation)
    1
    Windows Server, version 1803 (Server Core Installation)
    1
    Windows Server, version 1903 (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 KB4517389
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 KB4517389 for the affected products in your update management console.

Microsoft Download Center Links

    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4517389
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4519338
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4520008

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB4517389','KB4519338','KB4520008') }

References

    1
    Microsoft Security Response Center: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1322
    1
    KB article: https://support.microsoft.com/help/4519338
    1
    KB article: https://support.microsoft.com/help/4520008
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2019-1322
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-1322

Discovery Credit

DonkeysTeam, Edward Torkington and Phillip Langlois of NCC Group, Ilias Dimopoulos a.k.a gweeperx (@gweeperx)

PowerShell automationComing soon

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

References

↗ CVE-2019-1322↗ MSRC Advisory↗ NVD↗ KBKB4517389