Huge security hole in Internet Explorer for MacOS

Brad Lucier writes "Macintouch is reporting (go down the page a bit) that Internet Explorer 5.1, which comes preinstalled on MacOS X 10.1, has a huge security hole---when it downloads arbitrary programs encoded in the Macintosh's standard BinHex (.hqx) format, it automatically executes them. " Well I guess thats one way to make Unix insecure. Can anyone actually confirm this since it looks kinda sketchy. I wonder what someone's rationale would be for that:"Oh this won't hurt anyone, and saving that extra 'OK' click will be great!".

Comments

Re:Intrinsic Security in OS X

[mr3038]

Unless you're logged in as root... I don't know how damaging a malicious program can be

This is correct. However, this practically causes every local exploit to be remote exploit which makes things pretty much easier for an attacker. In addition it really doesn't matter if malicious code destroys only your personal data or your personal data and system libraries. You're fscked anyway!

Personally, I prefer OmniWeb

[ehintz]

I do occasionally use IE, when hitting one of those pages designed by MS only shops, but most of my browsing time is in OmniWeb (www.omnigroup.com). Problem solved.

As an added benefit, OmniWeb has options to disable banner ads (sorry VA), kill javascript popup windows, and it's just a generally nicer browser with more intelligent design decisions. And it keeps web pages from looking like NASCAR with all the bloody ads and popups. Did I mention how it kills ads and popups? Although I will admit IE is wicked fast under 10.1, OmniWeb is plenty fast enough.

As YOU DIDN"T read this article using said browser

[SteveM]

Its been standard in Mac OS for Stuffit Expander to automatically extract archives once downloaded. Isn't this issue related more to Stuffit Expander than IE?"

We all know how hard it is to click on a link and read the article, so I did it for you.

From the MacInTouch web site: "Every .hqx encoded classic application is decoded by Explorer itself (that's the default, Stuffit Expander isn't used) and then AUTOMATICALLY STARTED!"

I suggest that in the future you read the article in question before posting.

Steve M

Re:Not M$

[ehintz]

Internet Explorer on the MAC has nothing to do with Microsoft. It's developed, published, and installed by Apple.

Not. It's developed and published by the Microsoft Macintosh Business unit, which is a somewhat independent MS arm out in the SF Bay Area. Apple's only involvement is bundling IE with the OS. About the only way your statement is accurate is if you're trying to stipulate that IE for Mac has little to do with IE for windows, which is correct. In fact, it's not uncommon for IE/Windoze to inherit good ideas from IE/Mac.

And not to be picky, but it's Mac. Short for Macintosh. Not MAC, short for Media Access Control address, as in your NIC card.

Users are dumb

[nvainio]

My guess would be that most users would turn it off when they go into the Prefs to change the default download location

Yeah, just like "most users" turn off Java and JavaScript in their browsers? Or turn off macros in their Word and avoid macro viruses?

Not true. "Most users" are dumb. They have no clue what is the difference between "document" and "program". They can't or don't want to change settings. They just click the icon when asked and execute the virus or trojan.

Well, there will always be dumb users. They are not a problem, braindead defaults are. Without all these be-user-friendly-execute-it-all defaults, we would have less viruses and worms going around. Software developers should take their responsibility seriously.

Here's the fix (no sarcastic anti-MS comment here)

[Anonymous Coward]

Launch IE 5.1, go to the Explorer menu, then to Preferences.

Go to the "Receiving Files" options and DISABLE "Automatically decode MacBinary files" and "Automatically decode BinHex files".

Easy as that.

Not true

[Auckerman]

If the user has Classic running, which is VERY often the case, there is a problem. Classic is setuid root. All one would have to due is encode a malicious classic program as a .hqx, have it add itself to the startup procedure for OS X, and *poofie* instand backdoor.

Solution

[KFury]

1. Create script to toggle 'autoexec .hqx downloads' to FALSE
   
2. Insert the file into the X-10 popup banner

Problem solved.

Re:Near-Useless Security

[manly]

The problem is, the average "user" is not an admin. How is such a person going to have the knowledge to set themselves up with a user account to protect them from themselves?

You've raised an excellent point, that I'll paraphrase somewhat differently. Normal home PC users don't even begin to understand security well enough to craft any sort of security plan (or measures such as always running a virus scanner on downloads/attachments). There's a trade-off between security and convenience; Microsoft tends to err on the side of convenience (as in the topic of this article).

I think the short answer to your question is education. Windows XP is a secure multi-user OS, and it's now shipping on consumer PCs. Many users now will have no choice but to gain a better understanding of at least logging in, and what activities (app installation) aren't possible with a "restricted" user account.

Having said that, I found the Microsoft scheme to ease multiple user computing for consumers is incredibly convoluted. During installation, a superuser account synonymous with root on Unix named Administrator is created.

However, after booting Lose-XP for the first time and logging in as Administrator, you'll want to add user accounts. Lose-XP forces you to create a "Computer Administrator" account before you can create regular user accounts. After doing so, the Administrator account is hidden from XP's new simplified login screen. The point I'm trying to make is that a relatively basic concept is made more complex, even though the supposedly goal was to make the login screen simpler for Joe Schmoe.

In an OS that is designed to be operated by the average user, isn't the de-facto superuser account always going to be an issue?

It's an issue, but as alluded to before, it's being handled very differently now. In DOS and legacy Windows, there was only the de-facto superuser-level user. Now that XP is slated to become standard on all consumer PCs, this is obviously no longer the case.

Besides my earlier complaint that the handling of users is more complex than it used to be, there is I believe another wrinkle to it (that I read somewhere else). If you add accounts during installation of XP, they receive Administrator credentials instead of normal user privileges. Besides (pre-)installation, login is the first feature users will meet. I don't understand why accounts seem so convoluted in XP.

Finally, Mac OS X takes a different tack. From what I understand, all created accounts are user level accounts in the Unix sense. To access the admin-level account, you have to explicitly enable root. I don't know enough about OS X to comment, but on the face of things, this seems like a simple security policy that many users can actually understand if explained to them.

In short, unless users are going to treat their PCs as black-box Internet appliances (admin'd by a friend or relative), many of them will have to understand and admin their Windows boxes more than they've been accustomed to.

Not Stuffit's Fault

[Brownian Motion]

It is not Stuffit. It's Internet Explorer de-binhexing and executing the coded app all on it's own. Since you mention Stuffit, I'm not sure you understand what is going on as Stuffit does not have this behavior (nor is it involved).

It's not a feature of OS X (or the OS's fault in any way). I never noticed the beta-IE (used in OS 10.0[0-4] doing this, and I used it throughout. I rarely booted into OS 9 when OS X came out, and I used the beta fairly extensively as well.

IE is auto-decoding a binhex, then if it's an application, automatically executing it. No other version of IE does this. No other mac internet app does either. Others will auto-decode files for you, but leave it to you to launch them.

Sure, you can turn off the binhex pref, but without the added "feature" it is not a security risk to simply de-binhex a file (probably less dangerous than uu-decoding). Even a savvy user who perused every setting wouldn't know to uncheck "automatically decode binhex" to turn off a feature that's so stupid one wonders why someone would bother coding it (automatically running dl'd apps).

Now Stuffit has it's own security risk. By default, it will auto-mount any disk image it decodes. A disk image can be set to automatically launch an app when loaded. Hence, Stuffit can be made to do what IE is doing in a roundabout way. Personally, I think this "feature" should be turned off for disk images as well.

I use the slowest G4, and I've not noticed Stuffit being a hog, though it is annoying. It ripped through the 189 MB dev tool installer in a few seconds.

IE has other problems as well. It will reset my Internet prefs (usually just the dl folder, but sometimes it will set itself as the default web app). Just use Omniweb, and you get a nice spell checker to spell check your posts (I know I need it).

Re:Near-Useless Security

[Giant Hairy Spider]

As far as protection by using the Admin account, this is a basic tenet of security: assign only the necessary privileges for software to function.

Funny thing, the way this works out on a personal computer is that pretty much every program the user runs needs the ability to access the user's data. Otherwise the user is continually tripping over the restrictions and being forced to enter passwords.

The only reason you claim the Admin account provides "minimal" protection is because you believe the time and effort to restore a system is trivial.

Relative to the months of creative work and irreplacable personal data that can be lost, getting the local geek to spend a few hours reinstalling software is indeed trivial.

Even if that were the case, always running as the Admin account makes it a lot easier for a worm/virus to completely trash your system, taking down your valuable data files along with everything else.

The only thing it makes it easier to trash are the system files. The user data is totally at the mercy of any trojan they run.

Don't get me wrong, account restrictions could be used to provide better security on a personal computer. However, with rare exceptions, they aren't. The operating environment isn't designed for efficient permissions management and the users aren't sophisticated enough to understand the value anyway.

Multiuser OSs are just that, and not optimally designed for personal computers. The admin account is there to protect the system from the users, not to protect the users from foreign code. There are definitely improvements that could be made with a dedicated networked-PC OS designed with an eye to protecting the user's data from less-trusted network programs such as the web browser.

To sum it up, it isn't hard to imagine system features that would protect the user's data from internet code, and while a priviledged admin account could be a part of implementing those features, it doesn't provide them.