Discussion: Microsoft Security Advisory CVE-2019-0545: .NET Core Information Disclosure Vulnerability

[TravisEz13]

Microsoft Security Advisory CVE-2019-0545: .NET Core Information Disclosure Vulnerability

Executive Summary

Microsoft is aware of an information disclosure vulnerability exists in .NET Framework and .NET Core which allows bypassing Cross-origin Resource Sharing (CORS) configurations. An attacker who successfully exploited the vulnerability could retrieve content, that is normally restricted, from a web application.

The security update addresses the vulnerability by enforcing CORS configuration to prevent its bypass.

System administrators are advised to update PowerShell Core to an unaffected version (See Affected Software).

Discussion

Please use dotnet/corefx#34428 for discussion of the .NET aspects this advisory.

Affected Software

The vulnerability affects PowerShell Core prior to the following versions:

PowerShell Core Version	Fixed in
6.1	6.1.2
6.2	TBD

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.
2. 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

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-2019-0545

Revisions

V1.0 (Jan 15, 2019): Advisory published.

Version 1.0
Last Updated 2018-01-15

[ThomasNieto]

@TravisEz13 what do you think about moving this issue to a discussion?

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