CVE-2021-43890
Microsoft Windows AppX Installer Spoofing Vulnerability
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
1Exploited in Wild
YesDecision
Descriptions
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.
Una vulnerabilidad de SuplantaciĆ³n de Identidad de Windows AppX Installer
Microsoft Windows AppX Installer contains a spoofing vulnerability which has a high impacts to confidentiality, integrity, and availability.
CVSS Scores
SSVC
- Decision:-
Timeline
- 2021-11-16 CVE Reserved
- 2021-12-15 CVE Published
- 2021-12-15 Exploited in Wild
- 2021-12-29 KEV Due Date
- 2024-08-04 CVE Updated
- 2024-08-04 First Exploit
- 2024-08-17 EPSS Updated
CWE
CAPEC
References (5)
URL | Tag | Source |
---|---|---|
https://github.com/ChrisTitusTech/winutil/pull/26 | Issue Tracking | |
https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html | Media Coverage | |
https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks | Media Coverage |
URL | Date | SRC |
---|---|---|
https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer | 2024-08-04 |
URL | Date | SRC |
---|---|---|
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890 | 2024-07-24 |
URL | Date | SRC |
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Affected Vendors, Products, and Versions
Vendor | Product | Version | Other | Status | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 1809 Search vendor "Microsoft" for product "Windows 10 1809" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 1903 Search vendor "Microsoft" for product "Windows 10 1903" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 1909 Search vendor "Microsoft" for product "Windows 10 1909" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 2004 Search vendor "Microsoft" for product "Windows 10 2004" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 20h2 Search vendor "Microsoft" for product "Windows 10 20h2" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 21h1 Search vendor "Microsoft" for product "Windows 10 21h1" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 21h2 Search vendor "Microsoft" for product "Windows 10 21h2" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.16 Search vendor "Microsoft" for product "App Installer" and version " < 1.16" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 11 21h2 Search vendor "Microsoft" for product "Windows 11 21h2" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.11 Search vendor "Microsoft" for product "App Installer" and version " < 1.11" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 1507 Search vendor "Microsoft" for product "Windows 10 1507" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.11 Search vendor "Microsoft" for product "App Installer" and version " < 1.11" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 1709 Search vendor "Microsoft" for product "Windows 10 1709" | - | - |
Safe
|
Microsoft Search vendor "Microsoft" | App Installer Search vendor "Microsoft" for product "App Installer" | < 1.11 Search vendor "Microsoft" for product "App Installer" and version " < 1.11" | - |
Affected
| in | Microsoft Search vendor "Microsoft" | Windows 10 1803 Search vendor "Microsoft" for product "Windows 10 1803" | - | - |
Safe
|