CVE-2020-0840

Microsoft Windows AppX Deployment Service Hard Link Escalation of Privilege Vulnerability

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

An elevation of privilege vulnerability exists when Windows improperly handles hard links, aka 'Windows Hard Link Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0841, CVE-2020-0849, CVE-2020-0896.

Existe una vulnerabilidad de elevación de privilegios cuando Windows maneja inapropiadamente los enlaces físicos, también se conoce como "Windows Hard Link Elevation of Privilege Vulnerability"'. Este ID de CVE es diferente de CVE-2020-0841, CVE-2020-0849, CVE-2020-0896.

This vulnerability allows local attackers to escalate privileges on affected installations of Microsoft Windows. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within the AppX Deployment Service. By creating a hard link, an attacker can abuse the service to overwrite the contents of a chosen file. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of SYSTEM.

*Credits: JeongOh Kyea(@kkokkokye) of THEORI

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2019-11-04 CVE Reserved
2020-03-12 CVE Published
2024-08-04 CVE Updated
2024-09-08 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0840	2021-07-21

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				-		-		Affected
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				1607 Search vendor "Microsoft" for product "Windows 10" and version "1607"		-		Affected
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				1709 Search vendor "Microsoft" for product "Windows 10" and version "1709"		-		Affected
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				1803 Search vendor "Microsoft" for product "Windows 10" and version "1803"		-		Affected
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				1809 Search vendor "Microsoft" for product "Windows 10" and version "1809"		-		Affected
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				1903 Search vendor "Microsoft" for product "Windows 10" and version "1903"		-		Affected
Microsoft Search vendor "Microsoft"		Windows 10 Search vendor "Microsoft" for product "Windows 10"				1909 Search vendor "Microsoft" for product "Windows 10" and version "1909"		-		Affected
Microsoft Search vendor "Microsoft"		Windows 8.1 Search vendor "Microsoft" for product "Windows 8.1"				-		-		Affected
Microsoft Search vendor "Microsoft"		Windows Rt 8.1 Search vendor "Microsoft" for product "Windows Rt 8.1"				-		-		Affected
Microsoft Search vendor "Microsoft"		Windows Server 2012 Search vendor "Microsoft" for product "Windows Server 2012"				r2 Search vendor "Microsoft" for product "Windows Server 2012" and version "r2"		-		Affected
Microsoft Search vendor "Microsoft"		Windows Server 2016 Search vendor "Microsoft" for product "Windows Server 2016"				-		-		Affected
Microsoft Search vendor "Microsoft"		Windows Server 2016 Search vendor "Microsoft" for product "Windows Server 2016"				1803 Search vendor "Microsoft" for product "Windows Server 2016" and version "1803"		-		Affected
Microsoft Search vendor "Microsoft"		Windows Server 2016 Search vendor "Microsoft" for product "Windows Server 2016"				1903 Search vendor "Microsoft" for product "Windows Server 2016" and version "1903"		-		Affected
Microsoft Search vendor "Microsoft"		Windows Server 2016 Search vendor "Microsoft" for product "Windows Server 2016"				1909 Search vendor "Microsoft" for product "Windows Server 2016" and version "1909"		-		Affected
Microsoft Search vendor "Microsoft"		Windows Server 2019 Search vendor "Microsoft" for product "Windows Server 2019"				-		-		Affected