| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| 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. |
| <p>A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p> |
| <p>An elevation of privilege vulnerability exists because of overly permissive Access Control Lists (ACLs) on multiple system files, including the Security Accounts Manager (SAM) database. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p>
<p>An attacker must have the ability to execute code on a victim system to exploit this vulnerability.</p>
<p>After installing this security update, you <em>must</em> manually delete all shadow copies of system files, including the SAM database, to fully mitigate this vulnerabilty. <strong>Simply installing this security update will not fully mitigate this vulnerability.</strong> See <a href="https://support.microsoft.com/topic/1ceaa637-aaa3-4b58-a48b-baf72a2fa9e7">KB5005357- Delete Volume Shadow Copies</a>.</p> |
| <p>A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p>
<p><strong>UPDATE</strong> August 10, 2021: Microsoft has completed the investigation and has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. This security update changes the Point and Print default behavior; please see <a href="https://support.microsoft.com/help/5005652">KB5005652</a>.</p> |
| <p>A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory. The vulnerability could corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p>
<p>An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.</p>
<p>The security update addresses the vulnerability by modifying how Microsoft browsers handle objects in memory.</p> |
| A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.
The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory. |
| A spoofing vulnerability exists when Windows incorrectly validates file signatures. An attacker who successfully exploited this vulnerability could bypass security features and load improperly signed files.
In an attack scenario, an attacker could bypass security features intended to prevent improperly signed files from being loaded.
The update addresses the vulnerability by correcting how Windows validates file signatures. |
| <p>An elevation of privilege vulnerability exists when the Windows Universal Plug and Play (UPnP) service improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code with elevated system privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p>
<p>To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted script or application.</p>
<p>The update addresses the vulnerability by correcting how the Windows UPnP service handles objects in memory.</p> |
| <p>A information disclosure vulnerability exists when TLS components use weak hash algorithms. An attacker who successfully exploited this vulnerability could obtain information to further compromise a users's encrypted transmission channel.</p>
<p>To exploit the vulnerability, an attacker would have to conduct a man-in-the-middle attack.</p>
<p>The update addresses the vulnerability by correcting how TLS components use hash algorithms.</p> |
| <p>A remote code execution vulnerability exists when Windows Media Audio Decoder improperly handles objects. An attacker who successfully exploited the vulnerability could take control of an affected system.</p>
<p>There are multiple ways an attacker could exploit the vulnerability, such as by convincing a user to open a specially crafted document, or by convincing a user to visit a malicious webpage.</p>
<p>The security update addresses the vulnerability by correcting how Windows Media Audio Decoder handles objects.</p> |
| <p>An information disclosure vulnerability exists when the Windows kernel improperly initializes objects in memory.</p>
<p>To exploit this vulnerability, an authenticated attacker could run a specially crafted application. An attacker who successfully exploited this vulnerability could obtain information to further compromise the user’s system.</p>
<p>The update addresses the vulnerability by correcting how the Windows kernel initializes objects in memory.</p> |
| <p>An elevation of privilege vulnerability exists when the Connected User Experiences and Telemetry Service improperly handles file operations. An attacker who successfully exploited this vulnerability could gain elevated privileges on the victim system.</p>
<p>To exploit the vulnerability, an attacker would first have to gain execution on the victim system, then run a specially crafted application.</p>
<p>The security update addresses the vulnerability by correcting how the Connected User Experiences and Telemetry Service handles file operations.</p> |
| <p>An information disclosure vulnerability exists when the Windows kernel improperly handles objects in memory. An attacker who successfully exploited this vulnerability could obtain information to further compromise the user’s system.</p>
<p>To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted application. The vulnerability would not allow an attacker to execute code or to elevate user rights directly, but it could be used to obtain information that could be used to try to further compromise the affected system.</p>
<p>The update addresses the vulnerability by correcting how the Windows kernel handles objects in memory.</p> |
| An elevation of privilege vulnerability exists when the Windows Ancillary Function Driver for WinSock improperly handles memory.
To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.
The security update addresses the vulnerability by correcting how the Windows Ancillary Function Driver for WinSock handles memory. |
| An elevation of privilege vulnerability exists in the way that the dnsrslvr.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions.
To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application.
The security update addresses the vulnerability by ensuring the dnsrslvr.dll properly handles objects in memory. |
| An elevation of privilege vulnerability exists when the Windows Function Discovery SSDP Provider improperly handles memory.
To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.
The security update addresses the vulnerability by correcting how the Windows Function Discovery SSDP Provider handles memory. |
| An information disclosure vulnerability exists in the Windows kernel that could allow an attacker to retrieve information that could lead to a Kernel Address Space Layout Randomization (ASLR) bypass. An attacker who successfully exploited the vulnerability could retrieve the memory address of a kernel object.
To exploit the vulnerability, an attacker would have to log on to an affected system and run a specially crafted application.
The security update addresses the vulnerability by correcting how the Windows kernel handles memory addresses. |
| An information disclosure vulnerability exists when DirectWrite improperly discloses the contents of its memory. An attacker who successfully exploited the vulnerability could obtain information to further compromise the user’s system.
There are multiple ways an attacker could exploit the vulnerability, such as by convincing a user to open a specially crafted document, or by convincing a user to visit an untrusted webpage.
The security update addresses the vulnerability by correcting how DirectWrite handles objects in memory. |
| An elevation of privilege vulnerability exists when the Windows kernel fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application to take control of an affected system.
The update addresses the vulnerability by correcting how the Windows kernel handles objects in memory. |
| An elevation of privilege vulnerability exists when the "Public Account Pictures" folder improperly handles junctions.
To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.
The security update addresses the vulnerability by correcting how Windows handles junctions. |
