Heads up! CVE-2018-0875

The MSRC published the following details about CVE-2018-0875 | .NET Core Denial of Service Vulnerability

The .Net Core vulnerability is documented on https://github.com/dotnet/announcements/issues/62. Fine, no problem with that.

But, the version 1.0 of the advisory for CVE-2018-0875 is wrong about PowerShell Core because it just lists 6.0.0 as affected.

It appears actually that both PowerShell Core 6.0.0 and 6.0.1 are affected by CVE-2018-0875.
The CVE-2018-0875 vulneralbility is a Hash Collision issue that can cause a Denial of Service.

If you’ve got PowerShell Core, you need to update to version 6.0.2 using this link


PowerShell Core is a self contained application that has coreclr embedded as well as other assemblies.
PowerShell Core has been updated to target the updated .NET Core runtime, recompiled and released on this page.


MSRC security guidance: the dashboard

I’ve shown how to get the latest release note in the previous blog post

I’ll now show what can be done with the main “Security Updates” dashboard without the API key available on this page: Security Update Guide > Dashboard

I’ve published two functions: a private one named Get-MSRCDashBoardPage and a public one named Get-MSRCDashBoard

The first private function Get-MSRCDashBoardPage aims at downloading a specific dashboard page based on a time frame. By default, without giving parameters, if there are data published based on the current date, the function gets the first page. There are 3 parameters that can be passed to the function to get another page number and specify another After and Before date. It’s a private function because it’s used by its public counterpart where it’s called recursively for every page found in a specified time range.

As you can see, we get many properties back, much more than what’s displayed by the web interface. 🙄

The second public function Get-MSRCDashBoard aims at doing the same thing as its private counterpart. The difference is that there isn’t a “Page” parameter. It downloads the first page based on the time range specified, it then gets the total number of pages available and calls recursively its private counterpart to download each page.

Now, let’s see this function in action with some examples:

    • Here’s how to get all the pages on the Dashboard published in January 2018:
Get-MSRCDashBoard -After 01/01/2018 -Before 01/31/2018
    • Here’s how to export to CSV all the dashboard data about security updates published this month (after the second Tuesday)
# Save every page to a CSV file
Get-MSRCDashBoard |
Export-Csv -Path ~/Documents/MSRCDashBoard.$((Get-Date).ToString('yyyy-MM')).csv

# Read the CSV and use Out-GridView to look and filter data
Import-CSV ~/Documents/MSRCDashBoard.$((Get-Date).ToString('yyyy-MM')).csv | 

The first command saves every page to a CSV file and the second one reads the CSV file and sends the data to Out-GridView so that you can look and filter data.

    • Here’s how you can display the same properties as the web interface for February 2018:
Get-MSRCDashBoard -After 02/01/2018 -Before 02/28/2018  |
Select publishedDate,cveNumber,Name,Platform,articleTitle1,
downloadTitle1,articleTitle2,downloadTitle2,severity,impact | 

    • Here’s how you can display the same properties as the web interface for this month:
Get-MSRCDashBoard |
Select publishedDate,cveNumber,Name,Platform,articleTitle1,
downloadTitle1,articleTitle2,downloadTitle2,severity,impact | 

Let’s compare the Out-Gridview and the web interface:

PS: The two functions work in PowerShell Core but the “Out-Gridview” cmdlet used in examples isn’t available in PowerShell Core.

MSRC security guidance: about release notes

I’ve recently talked about a shortcoming of release notes published on the Security Update Guide > Dashboard in the following blog post

As you can see, there’s only the latest release note available. You cannot see previous ones.
If you want to read any release note ever published, you can.
I’ve kept a list of these on this page.

The same shortcoming also exists if you want to retrieve data using some automation.
Whatever date values you submit in a post request, you always get only the latest release note 😦

I’ve started a new project about the MSRC Microsoft Security Updates API in this github repository. I’ve documented why I started this project.
The last point is about to showcase some functions to get data from the portal without using an API key.

Here’s the first example with release notes:
I’ve published so far two functions: Get-MsrcReleaseNoteId and Get-MsrcReleaseNotePage

The first function Get-MsrcReleaseNoteId uses a post request to retrieve the latest release note available and doesn’t have any parameter.


It shows the release note Id (a GUID) that can be passed to the second function Get-MsrcReleaseNotePage by property name in order to retrieve the release note content as a json object.

Get-MSRCReleaseNoteId | Get-MSRCReleaseNotePage | fl

Notice that the note property is somehow html formatted and would need to be sanitized.

These are not the only functions I’ll showcase, stay tuned 🙂

You know what would be great about release notes:

  • It would be nice to be able to retrieve any release note using some datetime parameters (to addresss the above shortcoming).
  • It would be nice to retrieve any release note in either XML or JSON like the original MSRC Microsoft Security Updates API allows.
  • Instead of having a pseudo-html formatted string, I also would like to be able to get the Notes content as an object that has a title, a description, a list of affected software and the list of known issues.