Tab-completion in Mac open/save dialogs

Here is a nifty keyboard shortcut for my Mac readers (wait, that’s all my readers… all 2 of them).

via Lifehacker

No DRM, please

Steve Jobs has some thoughts on music.

Apple Store Fifth Avenue, NYC

Wow. Check out these pictures.

Digging into the latest Mac security flaw

Update: Apple has released a security update that addresses this issue.

Earlier this week a very serious Mac OS X security flaw was reported at heise online, and is now making the rounds at various tech outlets. Although the original report is accurate, some major news sites seem to missing the important details.

So I’ll reiterate here:

1. Yes, this is a very serious problem.
2. No, using Firefox instead of Safari will not completely mitigate the risks.
3. Apple needs to address this immediately (and by all accounts, it is doing just that).

I’m curious to see how Apple patches this hole. Because as I see it the actual flaw is deep within Mac OS X itself–in how the OS associates files with applications. Let me take a few minutes to explain.

Like Windows, in most cases the Mac consults a central file type registry when opening a file. So for example, double-clicking a .JPG opens the file in Preview, and double-clicking a .TXT opens the file in TextEdit.

However, the Mac is unique in how it also allows the default association to be overridden on a file-by-file basis. So one can say, “open .JPG files by default in Preview, but open this particular sunflower.jpg file in Photoshop”. One can even tell the Mac to associate sunflower.jpg with an application that doesn’t normally accept .JPG files. What’s more, this overriding association is not stored in a central registry. Rather, the association is stored within the sunflower.jpg itself, in a hidden resource fork.

Maybe you can see where this is going: what if sunflower.jpg is not really an image at all? What if it contains a malicious payload? And finally, what if this so-called .JPG is manually associated with an application that will execute its payload? I’ll leave out the exact recipe, but let’s just say that the Terminal application and shell scripts are involved, and the results are not pretty.

Essentially Mac OS X right now makes it very easy to package up the perfect trojan horse: the file is named as a .JPG, it even shows up with a .JPG icon in the Finder. But if someone double-clicks it, any script or application could be executed. Conceivably my home directory could get deleted before I knew what was happening.

In itself this is a pretty nasty vulnerability. But it gets much worse. This trojan file can be easily placed in a ZIP archive and emailed, IM’d or downloaded from one computer to another, and by virtue of the Mac’s enhanced zip/unzip tools, the resource fork remains intact: in other words, the deadly application association survives the transmission.

And now here’s the kicker: by default Safari automatically decompresses .ZIP files, and if the archive contains a single file with a “safe” extension, Safari automatically opens the file. In other words, a trojan file can be delivered and transparently executed with no user intervention: all it takes is a visit to a malicious web page.

Until Apple issues a patch, here’s what you can do:

1. If you use Safari, immediately disable the “Open safe files after downloading” option in its general preferences.
2. Never open the contents of a suspicious ZIP file, even if they seem like normal documents.
3. Use the Finder’s “Get Info” command to double-check that a file’s application association has not been tampered with.

You can also try this harmless proof-of-concept to see if your system is vulnerable.

Teetering on the brink

I was all ready for a spectacular hard drive crash, and then tonight something unexpected happened: my PowerBook’s AC adapter stopped working. Without a way to recharge the battery, my precious PowerBook was on its way to becoming a 5-pound paperweight.

After a brief panic which involved backing up my most important files (onto my iPod mini), I searched the Apple support pages with my last few minutes of battery power. As it turns out, this is a common problem with Apple’s power supplies: a loose connection develops where the DC cord meets the power brick.

And no, it seems a replacement AC adapter won’t be covered under my $300 extended warranty. Apparently any problems of this sort are inevitably due to “improper use”. Apple kindly mentions this policy twice in their troubleshooting document.

It’s hard to believe this machine is already on it’s last legs–with the dying hard drive and now the AC problems–after only a year and a half. Tomorrow I’m off to the Apple Store to get some answers. Wish me luck!

Catastrophic hard drive failure in 5… 4…

I just noticed that when I tilt my PowerBook sideways, the hard drive stops working.

Here’s a fun experiment: I’ll launch a program, browse to a folder of large images, or start some other disk intensive task and then lift the computer from my lap. Everything literally grinds to a halt, and I’m presented with the dreaded spinning beach ball of death. As soon as a place the computer on a level surface everything returns to normal.

I know what you’re thinking. No, this can’t be good.

True, my PowerBook has been acting flakey recently. The occasional crash, slow down, and odd fan noises even prompted me to call Apple technical support a few weeks ago. Their suggestion? Run the hardware diagnostics. The tests indicated nothing was wrong, and that was the end of that.

But now I have plan. I’ll run the hardware diagnostics sideways.