CVE-2023-38180

.NET and Visual Studio Denial of Service Vulnerability

Microsoft Security Advisory CVE-2023-38180: .NET Denial of Service Vulnerability

<a name="executive-summary"></a>Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core 2.1, .NET 6.0, and .NET 7.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A vulnerability exists in Kestrel where, on detecting a potentially malicious client, Kestrel will sometimes fail to disconnect it, resulting in denial of service.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/269

<a name="mitigation-factors"></a>Mitigation factors

If your application is running behind a reverse proxy, or Web Application Firewall, which has its own mitigations against HTTP based attacks this issue may be mitigated by the proxy or WAF

<a name="affected-software"></a>Affected software

• Any .NET 7.0 application running on .NET 7.0.8 or earlier.
• Any .NET 6.0 application running on .NET 6.0.19 or earlier.

If your application uses the following package versions, ensure you update to the latest version of .NET.

<a name=".NET 7"></a>.NET 7

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 7.0.0, <= 7.0.9 | 7.0.10 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 7.0.0, <= 7.0.9 | 7.0.10 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 7.0.0, <= 7.0.9 | 7.0.10

<a name=".NET 6"></a>.NET 6

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv | >= 6.0.0, <= 6.0.20 | 6.0.21 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 6.0.0, <= 6.0.20 | 6.0.21 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 6.0.0, <= 6.0.20 | 6.0.21 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 6.0.0, <= 6.0.20 | 6.0.21

<a name="ASP.NET Core 2.1"></a>ASP.NET Core 2.1

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv | <= 2.1.39 | 2.1.40 Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets | <= 2.1.39 | 2.1.40

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

If you have a runtime or SDK with a version listed, or an affected package listed in affected software, you're exposed to the vulnerability.

<a name="how-fix"></a>How do I fix the issue?

• To fix the issue please install the latest version of .NET 6.0 or .NET 7.0. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
• If you are using one of the affected packages, please update to the patched version listed above.
• If you have .NET 6.0 or greater installed, you can list the versions you have installed by running the dotnet --info command. You will see output like the following;

.NET Core SDK (reflecting any global.json):

 Version:   6.0.300
 Commit:    8473146e7d
…

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.110 and .NET Runtime 7.0.10.

Security Fix(es):

• dotnet: RCE under dotnet commands (CVE-2023-35390)

• dotnet: Kestrel vulnerability to slow read attacks leading to Denial of Service attack (CVE-2023-38180)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.121 and .NET Runtime 6.0.21.

Security Fix(es):

• dotnet: RCE under dotnet commands (CVE-2023-35390)

• dotnet: Kestrel vulnerability to slow read attacks leading to Denial of Service attack (CVE-2023-38180)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET and Visual Studio Denial of Service Vulnerability

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.110 and .NET Runtime 7.0.10.

Security Fix(es):

• dotnet: RCE under dotnet commands (CVE-2023-35390)
• dotnet: Kestrel vulnerability to slow read attacks leading to Denial of Service attack (CVE-2023-38180)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.110 and .NET Runtime 7.0.10.

Security Fix(es):

• dotnet: RCE under dotnet commands (CVE-2023-35390)
• dotnet: Kestrel vulnerability to slow read attacks leading to Denial of Service attack (CVE-2023-38180)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.121 and .NET Runtime 6.0.21.

Security Fix(es):

• dotnet: RCE under dotnet commands (CVE-2023-35390)
• dotnet: Kestrel vulnerability to slow read attacks leading to Denial of Service attack (CVE-2023-38180)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.121 and .NET Runtime 6.0.21.

Security Fix(es):

• dotnet: RCE under dotnet commands (CVE-2023-35390)
• dotnet: Kestrel vulnerability to slow read attacks leading to Denial of Service attack (CVE-2023-38180)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET and Visual Studio Denial of Service Vulnerability

.NET and Visual Studio Denial of Service Vulnerability

.NET and Visual Studio Denial of Service Vulnerability

USN-6278-1 fixed several vulnerabilities in .NET. This update provides the corresponding updates for Ubuntu 22.04 LTS.

Original advisory details:

It was discovered that .NET did properly handle the execution of certain commands. An attacker could possibly use this issue to achieve remote code execution. (CVE-2023-35390)

Benoit Foucher discovered that .NET did not properly implement the QUIC stream limit in HTTP/3. An attacker could possibly use this issue to cause a denial of service. (CVE-2023-38178)

It was discovered that .NET did not properly handle the disconnection of potentially malicious clients interfacing with a Kestrel server. An attacker could possibly use this issue to cause a denial of service. (CVE-2023-38180)