10.5.3 Mach Kernel Bug

[pendragon]

For most, after 10.5.3 has been installed, the file “mach_kernel.ctfsys” is invisible. A quick check of the Finder does not (normally) identify such a critter. And that's how it should be.

But if you drag the icon of your hard drive to the Dock, and then open that, the mach_kernel.ctfsys file is (now) visible.

Additionally, when others are connected to your machine via your network, they too will be able to see the mach_kernel.ctfsys  file. Thus, they are able, either innocently or maliciously, to cause harm.

The solution:

In Terminal:

1. At the prompt, enter (but without the quotes):

“sudo chflags hidden /mach_kernel.ctfsys” (you may want to cut & paste this)

2. You will then need to enter your password. Note: even though you enter your PW, there is no indication of such, but don’t worry about it.

3. After your PW has been entered, hit Return.

4. Quit Terminal.

That’s it. AFAIK, this fix has no side affects. Indeed it worked for me. Still, it is best to have a verified backup.

[Gregg]

QUOTE(pendragon @ May 30 2008, 08:36 AM) <{POST_SNAPBACK}>

when others are connected to your machine via your network, they too will be able to see the mach_kernel.ctfsys  file. Thus, they are able, either innocently or maliciously, to cause harm

And if that never happens, do I need to "fix" it?

(I haven't even installed the update yet!)

[pendragon]

Gregg: "And if that never happens, do I need to "fix" it?"

Not really, having a normally invisible file visible, should not otherwise cause a problem. All you need do is avoid changing that file (that's why Apple makes them invisible). And of course, if you do not put your HD icon in the Dock and use Stacks, then you are unlikely to even see the file.

But my knowledge of such is quite limited. Indeed, I tend to shy away from Eunuchs.

[Xairbusdriver]

The OS does a reasonable job of hiding stuff a user shouldn't touch. But as an Admin user, it is quite easy to use the Finder->Go->Go to Folder menu and type in any file you might no the name of, whether it's hidden or not. Not sure a non-Admin user can do that...

Of course, the files Permissions may throw up a slight barrier but that can be changed, again as an Admin, by using the Get Info function.

The above examples are just two reasons not to run as Admin, unless you have locked yourself into a room and have no extra 'personalities!' But most of us run as Admin, anyway. Even having Automatic Log In set up! Convenience usually wins over security, especially on a Mac...

[Gregg]

QUOTE(pendragon @ May 30 2008, 12:25 PM) <{POST_SNAPBACK}>

, if you do not put your HD icon in the Dock and use Stacks,

Nope. And I don't even know what I'm missing!