Windows AppX Deployment Extensions Elevation of Privilege Vulnerability (CVE-2019-1385) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTWindows AppX Deployment Extensions component running on Windows 10 and Windows Server environments.
An authenticated local attacker can execute a specially crafted application to access system files, leading to full SYSTEM privilege escalation.
Apply the official Microsoft cumulative security updates immediately and restrict symbolic link creation privileges for non-administrative users.
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
The primary remediation is to apply the official Microsoft cumulative security updates. Use the following PowerShell commands to check and force-install the required security patches:
# Install and use PSWindowsUpdate module to apply the security updates
Install-Module PSWindowsUpdate -Force -Verbose
Get-WindowsUpdate -KBArticleID KB4520062, KB4519978 -Install -AcceptAll -AutoReboot2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, restrict the creation of symbolic links to administrative users only using the local security policy tool:
# Export current security policy, restrict SeCreateSymbolicLinkPrivilege, and reapply
secedit /export /cfg secpolicy.inf
# Edit secpolicy.inf to ensure SeCreateSymbolicLinkPrivilege is restricted to *S-1-5-32-544 (Administrators)
secedit /configure /db secedit.sdb /cfg secpolicy.inf /areas USER_RIGHTS3. Log Audit & IoC Verification Commands
Monitor the AppX Deployment Server operational logs for anomalous package installation attempts or permission errors:
# Query AppX Deployment Server operational event logs for warnings and errors
Get-WinEvent -LogName 'Microsoft-Windows-AppXDeploymentServer/Operational' |
Where-Object { $_.Level -le 3 } |
Select-Object TimeCreated, Id, Message -First 50 |
Format-Table -AutoSizeBlock 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
An elevation of privilege vulnerability exists in the Windows AppX Deployment Extensions when it improperly manages privileges during file system operations. Specifically, this is a CWE-59 (Improper Link Resolution Before File Access) vulnerability where a low-privileged user can create symbolic links or hard links in a writable directory, forcing the high-privileged AppX service to follow the link and manipulate arbitrary system files.
2. Exploitation Mechanics & Attack Scenario
To exploit this vulnerability, an attacker must first gain local access to the target Windows system with standard user privileges. The attacker then creates a symbolic link pointing to a critical system file (such as a system DLL or service executable) within a temporary directory used during AppX package deployment. When the AppX Deployment Service performs write operations under the SYSTEM context, it follows the link and overwrites or modifies the target system file, allowing the attacker to execute arbitrary code with elevated privileges.
3. Infrastructure & Business Impact
As this vulnerability is listed in the CISA KEV (Known Exploited Vulnerabilities) catalog, it represents a highly active threat vector that has been exploited in the wild. Local Privilege Escalation (LPE) allows an attacker to transition from a compromised low-privilege account to full SYSTEM control, facilitating lateral movement, credential dumping, and the deployment of ransomware across the enterprise network.
Official Vendor Advisories & References
An elevation of privilege vulnerability exists when the Windows AppX Deployment Extensions improperly performs privilege management, resulting in access to system files.To exploit this vulnerability, an authenticated attacker would need to run a specially crafted application to elevate privileges.The security update addresses the vulnerability by correcting how AppX Deployment Extensions manages privileges., aka 'Windows AppX Deployment Extensions Elevation of Privilege Vulnerability'.
Frequently Asked SecOps Questions (CVE-2019-1385)
FAQQ1. How critical is CVE-2019-1385 and is it actively exploited in the wild?
CVE-2019-1385 is rated CVSS 7.8 (HIGH) with a 30-day EPSS exploitation probability of 3.6%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2019-1385?
Primary impacted vendors include microsoft across windows, windows_10, windows_server. Scope summary: Windows 10 (versions 1709, 1803, 1809, 1903, etc.) and Windows Server (versions 1803, 1903, Server 2019) utilizing AppX Deployment Extensions.
Q3. What temporary mitigations or workarounds exist for CVE-2019-1385 before patching?
[Mitigation] Apply the official Microsoft cumulative security updates immediately and restrict symbolic link creation privileges for non-administrative users. 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-2019-1385
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
🔗 Related Advisories in Similar Stack (microsoft)
View Category →Windows IKE Extension Double Free Remote Code Execution Vulnerability (CVE-2026-33824)
[Affected Scope] Internet Key Exchange (IKE) Extension service running on Microsoft Windows and Windows Server operating systems
Windows Update Stack Privilege Escalation Vulnerability via Link Following (CVE-2026-81963) Technical Advisory
[Affected Scope] Microsoft Windows operating systems utilizing the Windows Update Stack
Windows Remote Access Connection Manager (RasMan) Null Pointer Dereference Local DoS Vulnerability (CVE-2026-21525) Technical Advisory
[Affected Scope] Windows and Windows Server operating systems utilizing the Windows Remote Access Connection Manager (RasMan) service.
Windows ALPC Heap-Based Buffer Overflow Privilege Escalation Vulnerability (CVE-2026-85880) Security Advisory
[Affected Scope] Locally authenticated users across Microsoft Windows operating systems
Subscribe to Daily Vulnerability Briefings & KEV Alerts
Concise morning briefings for SecOps, DevSecOps, and SRE teams covering newly exploited CVEs and mitigation priorities.