Vulnerability-Lookup

BDU:2022-01515 (CVE-2021-43890)

Vulnerability from fstec – Published: 2022-03-28 – Updated: 2026-08-07 – View on bdu.fstec.ru Exploit publicly available Yes Fixed

Title

Уязвимость установщика Microsoft App Installer, связанная с обходом аутентификации посредством спуфинга, позволяющая нарушителю проводить спуфинг-атаки

Summary

Уязвимость установщика приложений Microsoft App Installer связана с обходом аутентификации посредством спуфинга. Эксплуатация уязвимости может позволить нарушителю, действующему удаленно, проводить спуфинг-атаки с помощью специально созданного вредоносного пакета

Severity

7.6 (High) CVSS 2.0


                      
                        AV:N/AC:H/Au:N/C:C/I:C/A:C

7.1 (High) CVSS 3.0


                      
                        CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

Class

Architecture vulnerability

Status

Confirmed by the vendor

Exploitation

Authorization bypass, Injection

Incidents

Yes

Remediation

Software update

CWE

CWE-264 - Разрешения, привилегии и средства управления доступом
CWE-290 - Обход аутентификации посредством спуфинга

Aliases

CVE-2021-43890

References

6 references

URL
https://nvd.nist.gov/vuln/detail/CVE-2021-43890
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43890
https://www.cybersecurity-help.cz/vdb/SB2021112505
https://www.fortiguard.com/threat-signal-report/4340/newly-patched-windows-vuln…
https://www.cisa.gov/sites/default/files/csv/known_exploited_vulnerabilities.csv
https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-…

Impacted products

1 product from 1 vendor

Vendors

Microsoft Corp

Products

Microsoft App Installer

Versions

до 1.11 (Microsoft App Installer)

Product types

Application software

Platforms

Microsoft Corp Windows 10 - 64-bit, Microsoft Corp Windows 10 - 32-bit, Microsoft Corp Windows 10 1709 - 64-bit, Microsoft Corp Windows 10 1709 - 32-bit, Microsoft Corp Windows 10 1803 - 64-bit, Microsoft Corp Windows 10 1803 - 32-bit, Microsoft Corp Windows 10 1809 - 64-bit, Microsoft Corp Windows 10 1809 - 32-bit, Microsoft Corp Windows 10 1809 - ARM64, Microsoft Corp Windows 10 1709 - ARM64, Microsoft Corp Windows 10 1803 - ARM64, Microsoft Corp Windows 10 1903 - 32-bit, Microsoft Corp Windows 10 1903 - 64-bit, Microsoft Corp Windows 10 1903 - ARM64, Microsoft Corp Windows 10 1909 - 32-bit, Microsoft Corp Windows 10 1909 - 64-bit, Microsoft Corp Windows 10 1909 - ARM64, Microsoft Corp Windows 10 2004 - 32-bit, Microsoft Corp Windows 10 2004 - 64-bit, Microsoft Corp Windows 10 2004 - ARM64, Microsoft Corp Windows 10 20H2 - ARM64, Microsoft Corp Windows 10 20H2 - 32-bit, Microsoft Corp Windows 10 20H2 - 64-bit, Microsoft Corp Windows 10 21H1 - 32-bit, Microsoft Corp Windows 10 21H1 - 64-bit, Microsoft Corp Windows 10 21H1 - ARM64, Microsoft Corp Windows 10 21H2 - 64-bit, Microsoft Corp Windows 10 21H2 - 32-bit, Microsoft Corp Windows 10 21H2 - ARM64

Mitigations

Использование рекомендаций: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43890

JSON

To clipboard

{
  "CVSS 2.0": "AV:N/AC:H/Au:N/C:C/I:C/A:C",
  "CVSS 3.0": "AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "Microsoft Corp",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "\u0434\u043e 1.11 (Microsoft App Installer)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439:\nhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43890",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "16.11.2021",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "07.08.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "28.03.2022",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2022-01515",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2021-43890",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0430\u0440\u0445\u0438\u0442\u0435\u043a\u0442\u0443\u0440\u044b",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Microsoft App Installer",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": "Microsoft Corp Windows 10 - 64-bit, Microsoft Corp Windows 10 - 32-bit, Microsoft Corp Windows 10 1709 - 64-bit, Microsoft Corp Windows 10 1709 - 32-bit, Microsoft Corp Windows 10 1803 - 64-bit, Microsoft Corp Windows 10 1803 - 32-bit, Microsoft Corp Windows 10 1809 - 64-bit, Microsoft Corp Windows 10 1809 - 32-bit, Microsoft Corp Windows 10 1809 - ARM64, Microsoft Corp Windows 10 1709 - ARM64, Microsoft Corp Windows 10 1803 - ARM64, Microsoft Corp Windows 10 1903 - 32-bit, Microsoft Corp Windows 10 1903 - 64-bit, Microsoft Corp Windows 10 1903 - ARM64, Microsoft Corp Windows 10 1909 - 32-bit, Microsoft Corp Windows 10 1909 - 64-bit, Microsoft Corp Windows 10 1909 - ARM64, Microsoft Corp Windows 10 2004 - 32-bit, Microsoft Corp Windows 10 2004 - 64-bit, Microsoft Corp Windows 10 2004 - ARM64, Microsoft Corp Windows 10 20H2 - ARM64, Microsoft Corp Windows 10 20H2 - 32-bit, Microsoft Corp Windows 10 20H2 - 64-bit, Microsoft Corp Windows 10 21H1 - 32-bit, Microsoft Corp Windows 10 21H1 - 64-bit, Microsoft Corp Windows 10 21H1 - ARM64, Microsoft Corp Windows 10 21H2 - 64-bit, Microsoft Corp Windows 10 21H2 - 32-bit, Microsoft Corp Windows 10 21H2 - ARM64",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0430\u043d\u043e\u0432\u0449\u0438\u043a\u0430 Microsoft App Installer, \u0441\u0432\u044f\u0437\u0430\u043d\u043d\u0430\u044f \u0441 \u043e\u0431\u0445\u043e\u0434\u043e\u043c \u0430\u0443\u0442\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u043f\u043e\u0441\u0440\u0435\u0434\u0441\u0442\u0432\u043e\u043c \u0441\u043f\u0443\u0444\u0438\u043d\u0433\u0430, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043f\u0440\u043e\u0432\u043e\u0434\u0438\u0442\u044c \u0441\u043f\u0443\u0444\u0438\u043d\u0433-\u0430\u0442\u0430\u043a\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0421\u0443\u0449\u0435\u0441\u0442\u0432\u0443\u0435\u0442 \u0432 \u043e\u0442\u043a\u0440\u044b\u0442\u043e\u043c \u0434\u043e\u0441\u0442\u0443\u043f\u0435",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u0420\u0430\u0437\u0440\u0435\u0448\u0435\u043d\u0438\u044f, \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 \u0438 \u0441\u0440\u0435\u0434\u0441\u0442\u0432\u0430 \u0443\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u0438\u044f \u0434\u043e\u0441\u0442\u0443\u043f\u043e\u043c (CWE-264), \u041e\u0431\u0445\u043e\u0434 \u0430\u0443\u0442\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u043f\u043e\u0441\u0440\u0435\u0434\u0441\u0442\u0432\u043e\u043c \u0441\u043f\u0443\u0444\u0438\u043d\u0433\u0430 (CWE-290)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0430\u043d\u043e\u0432\u0449\u0438\u043a\u0430 \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u0439 Microsoft App Installer \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u043e\u0431\u0445\u043e\u0434\u043e\u043c \u0430\u0443\u0442\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u043f\u043e\u0441\u0440\u0435\u0434\u0441\u0442\u0432\u043e\u043c \u0441\u043f\u0443\u0444\u0438\u043d\u0433\u0430. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e, \u0434\u0435\u0439\u0441\u0442\u0432\u0443\u044e\u0449\u0435\u043c\u0443 \u0443\u0434\u0430\u043b\u0435\u043d\u043d\u043e, \u043f\u0440\u043e\u0432\u043e\u0434\u0438\u0442\u044c \u0441\u043f\u0443\u0444\u0438\u043d\u0433-\u0430\u0442\u0430\u043a\u0438 \u0441 \u043f\u043e\u043c\u043e\u0449\u044c\u044e \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u0441\u043e\u0437\u0434\u0430\u043d\u043d\u043e\u0433\u043e \u0432\u0440\u0435\u0434\u043e\u043d\u043e\u0441\u043d\u043e\u0433\u043e \u043f\u0430\u043a\u0435\u0442\u0430",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": null,
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041d\u0430\u0440\u0443\u0448\u0435\u043d\u0438\u0435 \u0430\u0432\u0442\u043e\u0440\u0438\u0437\u0430\u0446\u0438\u0438, \u0418\u043d\u044a\u0435\u043a\u0446\u0438\u044f",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://nvd.nist.gov/vuln/detail/CVE-2021-43890\nhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43890\nhttps://www.cybersecurity-help.cz/vdb/SB2021112505\nhttps://www.fortiguard.com/threat-signal-report/4340/newly-patched-windows-vulnerability-cve-2021-43890-being-exploited-to-deliver-malware\nhttps://www.cisa.gov/sites/default/files/csv/known_exploited_vulnerabilities.csv\nhttps://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041f\u0440\u0438\u043a\u043b\u0430\u0434\u043d\u043e\u0435 \u041f\u041e \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-264, CWE-290",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0412\u044b\u0441\u043e\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 7,6)\n\u0412\u044b\u0441\u043e\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 7,1)"
}

CVE-2021-43890 (GCVE-0-2021-43890)

Vulnerability from cvelistv5 – Published: 2021-12-15 14:15 – Updated: 2026-08-06 03:55

Title

Windows AppX Installer Spoofing Vulnerability

Summary

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.

Severity

7.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

SSVC

Exploitation: active Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2021-12-14 00:00 UTC

CWE

Spoofing
CWE-noinfo Not enough information

Assigner

microsoft mitre root

References

6 references

URL	Tags
https://portal.msrc.microsoft.com/en-US/security-…	x_refsource_MISC
https://www.bleepingcomputer.com/news/microsoft/m…
https://thehackernews.com/2023/12/microsoft-disab…
https://www.microsoft.com/en-us/security/blog/202…
https://github.com/ChrisTitusTech/winutil/pull/26
https://www.cisa.gov/known-exploited-vulnerabilit…	government-resource

Impacted products

1 product

Vendor	Product	Version
Microsoft	App Installer	Affected: 1.0.0.0 , < publication (custom) cpe:2.3:a:microsoft:app_installer::::::::

Date Public

2021-12-14 08:00

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T04:10:17.079Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/ChrisTitusTech/winutil/pull/26"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-43890",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2021-12-14T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2021-12-15",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890"
              },
              "type": "kev"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "description": "CWE-noinfo Not enough information",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-06T03:55:23.978Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "government-resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "cpes": [
            "cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*"
          ],
          "platforms": [
            "Unknown"
          ],
          "product": "App Installer",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "publication",
              "status": "affected",
              "version": "1.0.0.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "datePublic": "2021-12-14T08:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "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.\nAn 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.\nPlease 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.\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\nDecember 27 2023 Update:\nIn 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.\nTo 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": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
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        }
      ],
      "problemTypes": [
        {
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            {
              "description": "Spoofing",
              "lang": "en-US",
              "type": "Impact"
            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2024-05-29T14:44:37.753Z",
        "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "shortName": "microsoft"
      },
      "references": [
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          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890"
        },
        {
          "url": "https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/"
        },
        {
          "url": "https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html"
        },
        {
          "url": "https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/"
        },
        {
          "url": "https://github.com/ChrisTitusTech/winutil/pull/26"
        }
      ],
      "title": "Windows AppX Installer Spoofing Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
    "assignerShortName": "microsoft",
    "cveId": "CVE-2021-43890",
    "datePublished": "2021-12-15T14:15:35.000Z",
    "dateReserved": "2021-11-16T00:00:00.000Z",
    "dateUpdated": "2026-08-06T03:55:23.978Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.