KB4343205/KB4343900 broke single-sign-on into Office 365 Sharepoint

[Bruce123]

Good morning,

 

We have the system setup so that when users opens IE it opens the URL for the Office 365 Sharepoint site and (automatically signs them into Office 365).

 

However, from the middle of last week we noticed that after opening IE11, and being forwarded through several URLs (as happens normally), the browser gets stuck on a white screen (the URL at the time being https://login.windows.net/(very long string), which is the one before being forwarded to the actual Sharepoint site (blahh.sharepoint.com/(string). Pressing refresh usually takes the user the the site.

 

I have managed to trace the cause to an update KB4343205 (Cumulative security update for Internet Explorer: August 14, 2018). Or August 14, 2018—KB4343900 (Monthly Rollup), which all of the fixes in KB4343205. Installing the above update raises IE update version (in the About menu) from 11.0.70 (fine) to 11.0.75 (issue).

 

On testing, the problem doesn't occur with Chrome (sign-sign-on works fine).

 

We use I Am Cloud for authentication into Office 365.

 

What would people advise? Raise the issue with I Am Cloud? They say the issue must be with Microsoft as the URL IE gets stuck on belongs to MS. Raise the issue with Microsoft? But why aren't all o365 users affected? Encourage our users to use Chrome instead, and hope that Microsoft may resolve the issue (assuming it's their issue to fix)?

 

Any advise is much appreciated.

 

Kind Regards,

 

Bruce.

Edited August 20, 2018 by Bruce123

[Bruce123]

Just an update on this:

 

Microsoft added SSO problems (on 22/08/2018) to the list of known issues with KB4343900 and on 30/08/2018 a new update was released to resolve this issue. I'm unsure why it seems that only a small subset of users were affected globally, it must pertain to particular configurations.

 

Thanks,

 

Bruce.

[Bruce123]

Update 2:

 

I tried manually installing this update (KB4343894) on a test PC and tried running IE11.

 

Still experiencing SSO issues, but when they seem to be even worth than before.

 

When I do eventually manage to get SSOed into o365 and click on the square of 9 dots at the top left to list all of the o365 Apps and click on one of the Apps (e.g. PowerPoint) it now completely closes IE (!). At least before, pressing F5 a few times would get you in, now the user seems to be totally blocked from it. Not sure if this relates to some complex interaction between this KB and third party software we have on PCs or if it's a general issue with this KB, which was supposed to resolve an issue with a previous KB (but just made it worse).

 

Good job we didn't rush to push this out to all PCs and servers, before testing.

 

This is reminiscent of the a previous patch to fix a patch to fix a patch to fix patch..., which we experienced earlier in the year.

 

Thanks,

 

Bruce.

Edited September 4, 2018 by Bruce123

[free780]

Why are you still using IE. Microsoft treat it as legacy and many sites don't function correctly?

[Bruce123]

Why are you still using IE. Microsoft treat it as legacy and many sites don't function correctly?

 

By implication you're asking why we haven't yet upgraded to Windows 10 (I noticed your profile image) and using Edge as the browser (or indeed Chrome)?

 

That being said, Microsoft are still supporting IE (just look at the number of updates that apply to it).

 

Thanks,

 

Bruce.