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 PowerShell/PowerShell#8654 for discussion of this advisory.
Please use dotnet/corefx#34428 for discussion of the .NET aspects this advisory.
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:
Run pwsh -v, then, check the version in the table in Affected Software to see if your version of PowerShell Core is affected.
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.
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.
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 PowerShell/PowerShell#8654 for discussion of this advisory. 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:
Advisory FAQ
How do I know if I am affected?
If all of the following are true:
pwsh -v, then, check the version in the table in Affected Software to see if your version of PowerShell Core is affected.pwshorpwsh.exe, then you are affected. This only existed for preview version of6.0.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