Microsoft Security Advisory CVE-2018-8415: Microsoft PowerShell Tampering Vulnerability

[TravisEz13]

Microsoft Security Advisory CVE-2018-8415: Microsoft PowerShell Tampering Vulnerability

Executive Summary

A tampering vulnerability exists in PowerShell that could allow an attacker to execute unlogged code.

To exploit this vulnerability, an attacker would need to log on to the affected system and run a specially crafted application.

The security update addresses the vulnerability by correcting log management of special characters.System administrators are advised to update PowerShell Core to version 6.0.5 or 6.1.1.

Discussion

Please use PowerShell/PowerShell#8254 for discussion of this advisory.

Affected Software

The vulnerability affects PowerShell Core prior to the following versions:

PowerShell Core Version	Fixed in
6.0	6.0.5
6.1	6.1.1
6.2	PowerShell/PowerShell#8253

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

Commit IDs

f8f3774d

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

Amirreza Niakanlahiji (@DissectMalware) of University of North Carolina at Charlotte

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-2018-8415

Revisions

V1.0 (November 13, 2018): Advisory published.
v1.1 (November 13, 2018): Updated Acknowledgments

Version 1.1
Last Updated 2018-11-13