SB2019121029 - Privilege escalation in Microsoft Windows AppX Deployment Server

Description

This security bulletin contains information about 2 vulnerabilities.

1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2019-1483)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to an error in junctions handling within the Windows AppX Deployment Server. A local user to run a specially crafted program to escalate privileges on the system.

2) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2019-1476)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to the way Windows AppX Deployment Service (AppXSVC) handles hard links. A local user can create a malicious application, launch it on the system and run processes in an elevated context, then install programs; view, change or delete data.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1483
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1476