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Little-known bug in XP causes explorer.exe to crash.
Posted: 07 Apr 2021, 18:22
by psu-explosion
I re-discovered a harmless glitch within Windows yesterday that can cause explorer.exe to crash simply by accessing a .url file. There is almost no documentation for this bug on the Internet, so I figured I'd post it here.
Creating a .url file containing the following text will trigger a crash whenever you access a folder containing it:
[InternetShortcut]
url=file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:file:
Saving this to your desktop is particularly annoying, because it will make explorer.exe crash over and over, because each time it tries to load your desktop, it will also try and load the file, thus crashing again, and the cycle will repeat.
Just delete the file through CMD to stop the crashes. In my testing, the only versions that are vulnerable to this are XP and Server 2003.
I have attached a file with the previously mentioned text. Just copy it to a folder of your choice, change the extension from .txt to .url, and that folder will become inaccessible through Explorer.
Little-known bug in XP causes explorer.exe to crash.
Posted: 10 Apr 2021, 04:55
by Kouto
Remnant of Active Desktop, possibly? Kinda feels like that...
Little-known bug in XP causes explorer.exe to crash.
Posted: 10 Apr 2021, 22:11
by psu-explosion
I have no idea. It doesn't occur in 2000, and I don't think Active Desktop had any changes from 2K to XP, so I'm at a loss. I'm not very familiar with the inner working of Active Desktop, though.
Little-known bug in XP causes explorer.exe to crash.
Posted: 11 Apr 2021, 00:30
by i430VX
To whom it may concern, explorer also blows up and dies if you enter it into the Run... prompt.
Little-known bug in XP causes explorer.exe to crash.
Posted: 11 Apr 2021, 10:01
by Kouto
i430VX wrote: ↑11 Apr 2021, 00:30
To whom it may concern, explorer also blows up and dies if you enter it into the Run... prompt.
What version of IE installed in both cases? Wonder if that does anything given how deeply IE6 is integrated in particular.
Little-known bug in XP causes explorer.exe to crash.
Posted: 11 Apr 2021, 10:12
by CRMX
I don't think IE version matters too much, due to the amount of IE6 stuff remaining even after upgrading to IE7/8. But don't take my word for it since I haven't tested this with all 3 IE versions yet.
Little-known bug in XP causes explorer.exe to crash.
Posted: 11 Apr 2021, 15:06
by i430VX
It is IE8 on my system.
Little-known bug in XP causes explorer.exe to crash.
Posted: 11 Apr 2021, 18:58
by psu-explosion
I have started more extensive tests today. My first finding: Internet Explorer version does matter.
On IE6, the bug works as I first detailed. Triggers an explorer.exe crash if it's interacted with in pretty much any way outside of CMD.
On IE7, it doesn't work... sort of. In my testing, explorer.exe will not crash if it sees the file. However, if you try and save a file to the directory that contains the .url file, the application will crash.
For example, if you try and save an image you created in Paint to a directory containing the file, Paint will crash & you will lose whatever unsaved work you had. However, explorer.exe stays alive.
On IE8, you get the same behavior as IE7. Which, of course, counters i430VX's experience, so there must be some variable I'm missing.
One thing I will test later is service packs. I'm performing all of this on XP SP2, but I have all the different versions at my fingertips. I have a suspicion that RTM will act much different.
Little-known bug in XP causes explorer.exe to crash.
Posted: 11 Apr 2021, 20:54
by Kouto
Interesting! As CRMX said, fragments of IE6 code remains in use on Windows Explorer even after IE7 or IE8 is installed so it's no wonder this happens. Bear in mind there are a few updates to IE6 - SP1/SP2, SV1 and "SP3" which seems to add 256bit encryption. Lots of different testing combos where IE6 is involved lol.
Little-known bug in XP causes explorer.exe to crash.
Posted: 06 Jun 2021, 04:05
by MichaelMaymays
psu-explosion wrote: ↑11 Apr 2021, 18:58
I have started more extensive tests today. My first finding: Internet Explorer version
does matter.
On IE6, the bug works as I first detailed. Triggers an explorer.exe crash if it's interacted with in pretty much any way outside of CMD.
On IE7, it doesn't work... sort of. In my testing, explorer.exe will not crash if it sees the file. However, if you try and save a file to the directory that contains the .url file, the application will crash.
For example, if you try and save an image you created in Paint to a directory containing the file, Paint will crash & you will lose whatever unsaved work you had. However, explorer.exe stays alive.
On IE8, you get the same behavior as IE7. Which, of course, counters i430VX's experience, so there must be some variable I'm missing.
One thing I will test later is service packs. I'm performing all of this on XP SP2, but I have all the different versions at my fingertips. I have a suspicion that RTM will act much different.
the explorer.exe toolbars (including the address bar and navigation buttons) are the same ones that IE use (this is true even in windows 10) which is why you can also use your IE toolbars in explorer.exe if you have any third party ones. so that means that explorer.exe has probably a decent amount in common with IE, more than you would think anyways regardless of active desktop. that may be part of the reason this happens anyways