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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2019-1064

Microsoft Windows AppX Deployment Service (AppXSVC) Privilege Escalation Vulnerability

KEVHIGH 7.8EPSS 6.89%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 5 April 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

An elevation of privilege vulnerability exists when Windows AppX Deployment Service (AppXSVC) improperly handles hard links. An attacker who successfully exploited this vulnerability could run processes in an elevated context. An attacker could then install programs; view, change or delete data. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The security update addresses the vulnerability by correcting how Windows AppX Deployment Service handles hard links.

CVSS 3.1
7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
6.89% probability · 94th percentile
CISA KEV
Listed 15 March 2022 · due 5 April 2022 · used in ransomware campaigns
Weakness
CWE-59
Affected
microsoft/windows 10 1607 · microsoft/windows 10 1703 · microsoft/windows 10 1709 · microsoft/windows 10 1803 · microsoft/windows 10 1809 · microsoft/windows 10 1903 · microsoft/windows server 1709 · microsoft/windows server 1803 · microsoft/windows server 1903 · microsoft/windows server 2016 · microsoft/windows server 2019
Source
secure@microsoft.com

CISA notes

Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2019-1064

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.