Empty Page Layouts

The masterpage outputs that wrapping HTML. What are you trying to achieve, maybe we'll start with that question first before attempting to modify base Kentico code files.

I'm just trying to restore the Layout functionality. Like I said, it's returning blank with that empty HTML. All layout tabs of all page templates are rendering this way.

What were the most recent changes? What hotfix is applied? Are there any errors in the Event log, browser console? Are you able to reproduce it on a vanilla Kentico 10 installation? Are the page templates using shared or custom layout? Maybe they where using a shared layout and sobody edited the page layout in Page layouts app.

We have the exact same issue on a Kentico 12, the page wasn't modified in the last 2 years.

So, what does the Event log, Windows event viewer say on the last actions? Are you running on last hotfix? In the recent months many old Kentico versions were hacked - because the old versions are not protected against new attacks obviously.

All hot fixes should be done, strange thing is that the page can be viewed in "preview mode" but when you click on the "page" / "design" tab in the admin of Kentico it's completely empty. The published page is also completely empty on the front.

The same page in another culture (fr-be) is visible on the front but also not in the admin.

So, what does the Event log say? What were the most recent changes? Somebody maybe deleted some shared layout or edited it without realizing what the consequences will be or maybe somebody removed the page placeholder web part from the master page.
Would it be possible to reproduce the issue using default Kentico installation with the sample Corporate site?

Nothing in the event log that suggests this error. Customer did not delete anything based on their info, default Kentico environment is a lot of setup I suppose...

Typically object versioning is turned on by default. I'd suggest looking at previous versions and see if anything happened. Also check another browser to rule out any updates or changes to your "default" browser.

Juraj, we were definitely hacked, as you mentioned. Nothing was showing up in the event logs, we had to go into the IIS logs to see that nonexistent directories were being hit and returning 200 to know something was amiss. These directories consisted of subfolders with one-word names and randomized HTML files within.

The one-word names were causing a redirect to a malicious site for any URL that contained them. For example, if our site had the word "win" anywhere in the URL, even if you tacked on the word to create what should have been a nonexistent URL generating a 404, it redirected. We've since mitigated the redirects but are still dealing with the source.

@Max - well, you are using very old version. There could be many vulnerabilities. Maybe also this one reported some time ago and last year some hackers used it again on old versions. That's why we recommend using latest version - it is not question whether but when the site will be hacked when using old version.