.NET Spoofing Vulnerability

.NET and Visual Studio Information Disclosure Vulnerability

ASP.NET Core Denial of Service Vulnerability

.NET and Visual Studio Elevation of Privilege Vulnerability

A remote code execution vulnerability exists in .NET software when the software fails to check the source markup of a file.An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user, aka '.NET Framework Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0605.

A remote code execution vulnerability exists in .NET software when the software fails to check the source markup of a file.An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user, aka '.NET Framework Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0606.

Microsoft Security Advisory CVE-2019-1301: Denial of Service Vulnerability in PowerShell Core

Executive Summary

A denial of service vulnerability exists when PowerShell Core or .NET Core improperly handles web requests. An attacker who successfully exploited this vulnerability could cause a denial of service against a PowerShell Core scripts.

The update addresses the vulnerability by correcting how the .NET Core handles web requests.

System administrators are advised to update PowerShell Core to an unaffected version (see affected software.)

Discussion

Please open a support question to discussion the PowerShell aspects of this advisory. Please use dotnet/announcements#121 for discussion of the .NET aspects this advisory.

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

The vulnerability affects PowerShell Core prior to the following versions:

| PowerShell Core Version | Fixed in | |-------------------------|-------------------| | 6.1 | 6.1.6 | | 6.2 | 6.2.3 | | 7.0 | unaffected | |5 | unaffected |

Advisory FAQ

How do I know if I am affected?

If all of the following are true:

1. Run pwsh -v, then, check the version in the table in Affected Software to see if your version of PowerShell Core is affected. 1. If you are running a version of PowerShell Core where the executable is not pwsh or pwsh.exe, then you are affected. This only existed for preview version of 6.0.

How do I update to an unaffected version?

Follow the instructions at Installing PowerShell Core to install the latest version of PowerShell Core.

Other Information

Reporting Security Issues

If you have found a potential security issue in PowerShell Core, please email details to secure@microsoft.com.

Support

You can ask questions about this issue on GitHub in the PowerShell organization. This is located at https://github.com/PowerShell/. The Announcements repo (https://github.com/PowerShell/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue where you can ask questions.

What if the update breaks my script or module?

You can uninstall the newer version of PowerShell Core and install the previous version of PowerShell Core. This should be treated as a temporary measure. Therefore, the script or module should be updated to work with the patched version of PowerShell Core.

Acknowledgments

Paul Ryman of VMware Sydney Engineering Team

Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure.

See acknowledgments for more information.

External Links

CVE-2019-1301

A denial of service vulnerability exists when .NET Framework and .NET Core improperly process RegEx strings, aka '.NET Framework and .NET Core Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0980, CVE-2019-0981.

It was discovered that RegEx strings were not properly processed, which can be exploited by anauthenticated remote attackers to cause a Denial of Service by sending specially crafted requests to a .NET Core application.

External references:

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0820

A denial of service vulnerability exists when .NET Framework or .NET Core improperly handle web requests, aka '.Net Framework and .Net Core Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0820, CVE-2019-0980.

An error related to IPAddress.TryCreate when processing certain web requests can be exploited by unauthenticated remote attackers to cause a Denial of Service by sending specially crafted requests to a .NET Core application.

External references:

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0981

A denial of service vulnerability exists when .NET Framework or .NET Core improperly handle web requests, aka '.Net Framework and .Net Core Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0820, CVE-2019-0981.

An infinite loop flaw related to URI.TryCreate when processing certain web requests can be exploited by unauthenticated remote attackers to cause a Denial of Service by sending specially crafted requests to a .NET Core application.

External references:

https://portal.msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2019-0980

A tampering vulnerability exists in NuGet software when executed in a Linux or Mac environment. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user.

A vulnerability exists in certain .Net Framework API's and Visual Studio in the way they parse URL's, aka '.NET Framework and Visual Studio Spoofing Vulnerability'.

An information disclosure vulnerability exists in .NET Framework and .NET Core which allows bypassing Cross-origin Resource Sharing (CORS) configurations, aka ".NET Framework Information Disclosure Vulnerability." This affects Microsoft .NET Framework 2.0, Microsoft .NET Framework 3.0, Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6, Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.7/4.7.1/4.7.2, .NET Core 2.1, Microsoft .NET Framework 4.7.1/4.7.2, Microsoft .NET Framework 3.5, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.6/4.6.1/4.6.2, .NET Core 2.2, Microsoft .NET Framework 4.7.2.

A tampering vulnerability exists when .NET Core improperly handles specially crafted files. An attacker who successfully exploited this vulnerability could write arbitrary files and directories to certain locations on a vulnerable system. However, an attacker would have limited control over the destination of the files and directories.

External References:

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8416

A denial of service vulnerability exists when System.IO.Pipelines improperly handles requests, aka "System.IO.Pipelines Denial of Service." This affects .NET Core 2.1, System.IO.Pipelines, ASP.NET Core 2.1.

A denial of service vulnerability exists when .NET and .NET Core improperly process XML documents, aka ".NET and .NET Core Denial of Service Vulnerability." This affects Microsoft .NET Framework 2.0, Microsoft .NET Framework 3.0, Microsoft .NET Framework 4.7.1, Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.7/4.7.1, Microsoft .NET Framework 4.6, Microsoft .NET Framework 3.5, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.6/4.6.1/4.6.2, Microsoft .NET Framework 4.6.2/4.7/4.7.1, .NET Core 2.0, Microsoft .NET Framework 4.7.2.

Case insensitive string comparison uses an insecure hashing algorithm which can be compromised in .NET Core 1.x (Unix) and .NET Core 2.0. The attack vector could be a Dictionary which uses case invariant keys.

.NET Core 1.0, 1.1 and 2.0 perform improper processing of XML documents. A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to a .NET Core application.

References: https://nvd.nist.gov/vuln/detail/CVE-2018-0764 https://github.com/dotnet/core/blob/master/release-notes/2.0/2.0.5.md https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0764 https://github.com/dotnet/corefx/commit/3f1155b

Microsoft .NET Framework 2.0 SP2, 3.0 SP2, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, .NET Core 1.0 and 2.0, and PowerShell Core 6.0.0 allow a security feature bypass vulnerability due to the way certificates are validated, aka ".NET Security Feature Bypass Vulnerability."