Microsoft Security Advisory CVE-2024-38095 | .NET Denial of Service Vulnerability

Executive Summary

Microsoft is releasing this security advisory to provide information about a vulnerability in PowerShell 7.2 and PowerShell 7.4. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A Vulnerability exists when System.Formats.Asn1 in .NET parses an X.509 certificate or collection of certificates, a malicious certificate can result in excessive CPU consumption on all platforms result in Denial of Service.

System administrators are advised to update PowerShell 7 to an unaffected version (see affected software).

Discussion

Please open a support question to discuss the PowerShell aspects of this advisory. Please use https://github.com/dotnet/runtime/issues/104622 for discussion of the .NET aspects this advisory.

Affected Software

The vulnerability affects PowerShell 7 prior to the following versions:

PowerShell 7 Version	Fixed in
7.2	7.2.22
7.4	7.4.4

The vulnerability affects PowerShell when running on the following operating systems:

Operating System	Affected
Windows	Yes
macOS	Yes
Linux	Yes

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 7 is affected.

How do I update to an unaffected version?

Follow the instructions at Installing PowerShell 7 to install the latest version of PowerShell 7.

Updating PowerShell 7 using Microsoft Update

Other Information

Reporting Security Issues

If you have found a potential security issue in PowerShell 7, 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.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

What if the update breaks my script or module?

You can uninstall the newer version of PowerShell 7 and install the previous version of PowerShell 7. This should be treated as a temporary measure. Therefore, the script or module should be updated to work with the patched version of PowerShell 7.

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-2024-38095

Revisions

V1.0 (July 23, 2024): Advisory published.

Version 1.0 Last Updated 2024-07-23

PowerShell / Announcements