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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2021-43890 Detail

Description

We have investigated reports of a spoofing vulnerability in AppX installer that affects Microsoft Windows. Microsoft is aware of attacks that attempt to exploit this vulnerability by using specially crafted packages that include the malware family known as Emotet/Trickbot/Bazaloader. An attacker could craft a malicious attachment to be used in phishing campaigns. The attacker would then have to convince the user to open the specially crafted attachment. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Please see the Security Updates table for the link to the updated app. Alternatively you can download and install the Installer using the links provided in the FAQ section. Please see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability. December 27 2023 Update: In recent months, Microsoft Threat Intelligence has seen an increase in activity from threat actors leveraging social engineering and phishing techniques to target Windows OS users and utilizing the ms-appinstaller URI scheme. To address this increase in activity, we have updated the App Installer to disable the ms-appinstaller protocol by default and recommend other potential mitigations.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/ChrisTitusTech/winutil/pull/26 Issue Tracking 
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890 Patch  Vendor Advisory 
https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html Press/Media Coverage  Third Party Advisory 
https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/ Press/Media Coverage  Third Party Advisory 
https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/ Exploit  Vendor Advisory 

This CVE is in CISA's Known Exploited Vulnerabilities Catalog

Reference CISA's BOD 22-01 and Known Exploited Vulnerabilities Catalog for further guidance and requirements.

Vulnerability Name Date Added Due Date Required Action
Microsoft Windows AppX Installer Spoofing Vulnerability 12/15/2021 12/29/2021 Apply updates per vendor instructions.

Weakness Enumeration

CWE-ID CWE Name Source
NVD-CWE-noinfo Insufficient Information cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

9 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-43890
NVD Published Date:
12/15/2021
NVD Last Modified:
07/24/2024
Source:
Microsoft Corporation