First Mac OS X Virus?

bubba451 writes "MacRumors reports on what may be the first virus to affect Mac OS X, disguised as screenshots for the upcoming Mac OS X 10.5 Leopard. From the report: 'The resultant file decompresses into what appears to be a standard JPEG icon in Mac OS X but was actually a compiled Unix executable in disguise. An initial disassembly reveals evidence that the application is a virus or was designed to give that impression.' The virus is said to also spread via Bonjour instant messaging." Update: 02/17 00:09 GMT by P : This is not a virus, it is a simple Trojan Horse: it requires manual user interaction to launch the executable. See Andrew Welch's dissection.

Phew!

Glad I just 'switched' to windows ;-)

(fp?)

FUD of the day

This story is the biggest FUD of the day.

1.) Several proof-of-concept viruses have been written for OS X in the past, so this isn't the "first." They never propagate.

2.) When you download this .tgz file in Safari, Safari warns you that it's an application, and you have to click to continue.

3.) When you run it, an admin password prompt is displayed by OS X, and you have to enter it to continue.

Like I said--FUD of the day.

Re:FUD of the day

... with the important exception of when you're running as an Admin user, in which case you don't get this important opportunity to prevent the program from modifying files it shouldn't.

What are you talking about? Admin accounts normally get password popups to do anything like this (system updates, system-wide installers, etc.). Are you saying in this specific instance it doesn't?

Re:FUD of the day

Mac admin accounts are not like Windows admin accounts. They are not root accounts. You still have to sudo to do any root-level administration.

Re:Phew!

Should have waited. Dvorak is predicting that Apple will adopt Windows [pcmag.com].

I wish I also got paid to be a crackhead.

Trojan Man?

Sounds more like a trojan to me. But the question is, how in the world did they get it to show up as a JPEG image and still be executable? And does this script do any damage beyond the user's home directory? I.E., does it have some sort of a rootkit? Or does it simply prompt the user for the root/admin/sudo password?

Somebody better wake up Apple and fix this application-looks-like-a-pretty-JPEG icon bug!!

Re:Trojan Man?

I guess they put the standard JPEG icon in the app's bundle...

Re:Trojan Man?

My file extensions show by default in all the OS X Tiger installations I've handled.

Regardless, this "virus" pops up an admin password prompt, like every other proof-of-concept OS X trojan that's been written in the past, which effectively stops it in its tracks. This isn't really news except to Apple-haters who can go "SEE NOW U'VE GOT VIRUSES LOLZ."

Re:Trojan Man?

There's this thing called reading the article... oh, right.

It's a "JPEG" because the author was clever enough to paste the icon of a JPEG onto the executable.
If the user is root, or possibly admin, the script writes files in /Library/InputManagers. If you aren't it does the same in the user Library.
No kit, just a prompt.

http://www.ambrosiasw.com/forums/index.php?showtop ic=102379 [ambrosiasw.com] as linked from MacRumors has a really good writeup on what is going on.

Re:Trojan Man?

An honest question (I'm pretty ignorant):

How can a user differentiate between an executable file with a pretty icon and a jpeg in OSX (or Linux for that matter)? In Windows there are file extensions so a trojan with an icon will still have to be called something.exe in order to do any damage. How can I tell the difference between a binary file with an icon and a file that doesn't execute any code with the absense of extensions?

Please don't laugh :(

Re:Trojan Man?

All you have to do is right click... oh, nm

Re:Trojan Man?

If, like many more computer literate users, you elect to "show all file extensions" (Finder:Preferences:Advanced), this "virus" (which is actually a trojan of course) will show up as YaddaYadda.jpg.app and you'll see that it's just a lame attempt at a trojan.

Actually, it seems that (as of 10.4.5, anyway) it'll show as 'YaddaYadda.jpg.app' even if you have the 'Show all file extensions' switched off - a bit of experimentation shows that if the first extension (in this case '.jpg') is a recognised file-type, then the '.app' gets shown as well.

So, from a display point of view:

• YaddaYadda.app -> YaddaYadda
  
• YaddaYadda.foo.app -> YaddaYadda.foo
  
• YaddaYadda.jpg.app -> YaddaYadda.jpg.app
  
• YaddaYadda.pdf.app -> YaddaYadda.pdf.app
  

... and so on.

Basically, if it's trying to impersonate another existing file-type, it'll tell you.

List View

That's a totally legitimate question.

If you choose "View as List" in the finder (equivalent to the Detail view in Windows), and then expand the window so that you can see the "Kind" column, the Finder will tell you the kind of file you're looking at. For example, Application, Picture, Document, etc.

The Finder looks at some stuff which is not visible to the user in determining this -- in addition to the ".app" file extension on Cocoa bundles, there are also the traditional Mac 'Type' and 'Creator' codes, stored in the file metadata in the resource fork. By setting a file's Type to "APPL," it becomes an executable. This is the traditional Macintosh analog to the UNIX eXecute bit (but arguably more flexible, since it also handles file typing), and is totally independent of the file name. But anything that you set this way will be clearly marked as an Application in List View, regardless of what you name it, or what kind of custom icon it has.

This is how the MP3Concept trojan worked, and how many old-school ResEdit tricks worked. You can have something that's legitimately named "Mp3Concept.mp3" and looks like an MP3 but is really an executable, by setting the Type and custom icons correctly. It's nothing new, people have been doing it for years. (There were a lot of ResEdit "hacks" that worked off of this principle -- for example, creating a dummy Excel document that gave a rude dialog when double-clicked.) I think it's because we've migrated away from OS 9 and the metadata concepts that people have forgotten how easy it is to do, and that the Mac still supports it.

Re:Trojan Man?

If the user is root, or possibly admin, the script writes files in /Library/InputManagers.

Um, why is my /Library chmod 775? It's that way on all four OS X machines that I can reach via SSH right now, two 10.4.x and two 10.3.x. Because there is no /Library/InputManagers in my /Library, so any program running under an admin account on my machine could create one. Admittedly, /Library/StartupItems being group-writable would be a much worse security violation (stuff in there runs as root at startup), and I have seen cases where installers will create one chmod 775 or 777, but I don't see any reason why a program that isn't setuid root (in other words, requiring the security dialog first) should be able to create new directories or drop files into /Library.

Anyhow, this is not a virus, it's a trojan. A virus attaches itself to existing executables (boot blocks included in the definition of "executables"). This is a trojan, and if it replicates, then it's a file-propagating worm (as opposed to the e-mail- and network- propagating worms that plague Windows). So far there is still no malware for OS X that doesn't depend upon human stupidity for propagation. Whether that be saving an e-mail attachment to disk and then double-clicking on its icon on the desktop (this thing won't auto-open while reading e-mail), or simply using bad username/password combinations allowing a brute-force break-in over SSH, there is still no sign of any kind of fully-automated malware for OS X.

In the meantime, I'm going to be doing a lot of "sudo chmod 755 /Library".

Re:Trojan Man?

Uhm, how are proposing to "fix" this? You can give your application any icon you want, and as long as it looks even remotely like the native JPEG-icon, 95% of users won't notice.

The only way would be some sort of flag that shows up on any icon that represents something executable, and that wouldn't be a fix but a completely new approach.

Re:Trojan Man?

Maybe we should be able to override the OS so that no matter what icon the executable file says it wants to display, the OS always shows an icon clearly depicting the fact that the file is an executable.

Re:Trojan Man?

I was thinking about this. I can't imagine it would be all that hard -- there is already a visual flag applied to all "alias" (that's symlink) files, so it doesn't seem like it would be out of the question to do something similar for executables, based on the eXecute bit.

However what I'm not sure about is how you'd make this work for MacOS bundles -- unlike UNIX applications they're not just single files; the thing that you click on in the Finder to launch a MacOS app (at least a Cocoa one) is actually a directory if you look at it in the Terminal, it just has the hidden suffix of ".app" (so for instance the program Mail in the finder is actually the directory/folder Mail.app). The actual executable file is normally buried somewhere within the folder -- usually like (appname).app/Contents/MacOS/executablefile.

I suppose what you'd have to do is put the visual flag on if a file was either a directory ending in ".app", or if the regular eXecute bit was set on a file itself.

Re:Trojan Man?

An even more novel solution: Apply a big fat red exclamation point to the bottom-right of the icon if the executable has never been run before--alongside prompting the user before running the executable for the first time (as is currently the case).

Re:Trojan Man?

Uhm, how are proposing to "fix" this?

When I download a dmg file with Safari, I get a warning if the dmg contains an executable. (Not sure if that's Safari doing the warning or the code that mounts the archive or what.) Something like this in the code that unpacks tar files would go a long way toward fixing it.

Devon

Re:Trojan Man?

Anyway, back to the present. A simple, welcome solution, would be to just show the names of applications in bold text. That would be helpful to power user and novice alike, and it would probably also look good.

I like it. Good idea.

While we're at it, maybe they can give us back our aliases in italics at the same time; that was a nice 'no brainer' feature if I ever saw one.

That will probably go over better with application developers than some sort of visual indicator on the application's icon that would mess up their pretty custom look. Bolded text is definitely the better way to go.

Re:Trojan Man?

Sounds more like a trojan to me. But the question is, how in the world did they get it to show up as a JPEG image and still be executable?

It definitely is a trojan, and a harmless one at that. It seems that if you have configured your computer correctly, you would have to enter your admin password in order to allow it to do any harm.

It doesn't really disguise as an image. It just uses the OS X standard icon for images as its own icon. However, it does not have a jpeg extension and if you select it in the finder, you will not get a preview thumbnail, thus you would know that opening in the Preview application (which you would do by double clicking) cannot work. Maybe, if you have set your Finder not to display extensions, or just didn't pay attention, you would try to open it in another image viewer, which would fail and not do any harm.

Re:Trojan Man?

It's almost impossible for a clueless user to run as root on an OS X box.

Actually running/logging-in as root requires either some non-trivial Terminal work, or going in through NetInfo Manager (a fairly intimidating config utility) and enabling the root account (which at least the time I did it, a few years ago, gave you some pretty stern warnings).

That's not to say that you can't have root-like privs -- the default first user on a Mac is an "Administrator," which just means that they can sudo -s and become root temporarily. However to do this you have to authenticate for every action. (Or every 5 minutes or so.) The MacOS "Administrator" level user is not as powerful as the WinXP type of Administrator (which is effectively a root account). Macs have three levels of users: root, Admins (who can sudo), and everyone else (who can't).

So yes, there are definitely ways that a clueless person could damage themselves with a trojan, if they just mindlessly type in their password into any box that comes up, regardless of the context in which they're being asked, but there is at least one more step stopping you from doing it compared to running on a Windows system.

It's not a virus...

Note the following from http://www.ambrosiasw.com/forums/index.php?showtop ic=102379 [ambrosiasw.com] :

You cannot be infected by this unless you do all of the following:

1) Are somehow sent (via email, iChat, etc.) or download the "latestpics.tgz" file

2) Double-click on the file to decompress it

3) Double-click on the resulting file to "open" it ...and then for most users, you must also enter your Admin password.

You cannot simply "catch" the virus. Even if someone does send you the "latestpics.tgz" file, you cannot be infected unless you unarchive the file, and then open it.

Re:It's not a virus...

Yes... Unfortunately the Windows user world has shown that more than enough people will

1. download it

2. double-click and decompress it.

3. double-click and execute it.

Re:It's not a virus...

Can you explain to me where the security flaw in OSX is in this case?

There is no double standard here.

Re:It's not a virus...

The flaw is that a file of one type is able to present itself as a file of another. This flaw was widely exploited in Windows a few years ago with the notorious "britney.jpg .vbs" type attacks, in which even though the icon was wrong (!!) people saw the file extension and opened it.

I think people are misunderstanding how OS X handles file type icons. The file isn't presenting itself as a file of another type. If you did a Get Info, it would still say Application. On OS X, you can copy and paste any icon into file in the Get Info window. I have cool Mario icons for my various external USB drives. Someone just copied and pasted the JPEG icon in this case.

The fact that clicking this thing prompts for a password means OS X is correctly protecting you from this kind of an attack. Beyond that, anyone entering the password and enabling admin access for this program is at fault, not OS X.

Re:It's not a virus...

Um.. no, completly different

In the windows scenario you have a real .JPG image which contains code insdie of it that crashes the Windows JPG image library. The code in the image is then executed. In essence in windows a .JPG image file can become an executable running as user admin. This executable now has full access over your computer. This image can be embedded in an e-mail/web page and will execute, launch and own your machine with having you do anything but go to a website or read your e-mail

In the Mac scenario you have an executable which is made to look like an image because its icon was changed. The computer itself knows that it isn't an image so it doesn't try to load it automatically from e-mail or web. This 'virus' is designed to trick the user. The user needs to double click and run the executable. It will then try to write into a protected directory and the OS will prompt the user for the admin password. If the user is dumb enough to click on a executable *and* enter the admin password there really isn't much else you can do. The executable never actually crashes any part of the OS to gain control of the OS and do something that the user doesn't authorize.

Hardware

Well, of course there's a mac virus now - virus writers have been comfortably writing to the intel platform for years, and now with the processor switch, all the viruses will be very easy to port over :)

Trojan?

How can it be a virus if it is a Trojan?
You have to execute it yourself, and that is why it is _not_ a virus.

Re:Trojan?

How can it be a virus if it is a Trojan?

OK, welcome to malware nomenclature 101. Will everyone please take their seats. Thank you. There are three basic classifications for malware:

• trojan - malicious application disguised as either a benign application or data.
• virus - a malicious application that copies itself into other locations infecting data or applications in an attempt to spread. Viruses often attempt to e-mail, IM, FTP, etc. themselves to other machines.
• worm - a worm is a virus that auto-propagates. That is to say it sends copies of itself automatically and traditionally without any user intervention.

This particular malware is a trojan (partly disguised as a jpg) which them copies itself to a new location on your drive and modifies a few commonly used applications in order to spread itself via they Bonjour discovery and file transfer mechanism in OS X. It requires human intervention to extract itself run, spread, and for download. I'd call this a virus to be clear about its functionality.

Eh?

Wouldn't shock me if it was written by a software company whose name rhymes with 'pedantic'.

Reminds me of old Applescript "hacks"

Back in high school we used to make little mean scripts in Applescript. Since there was no concept of security or multiple users in Mac OS 7 and 8, the script could do all sorts of nasty damage. All you had to do was compile/"save as" a standalone executable application from the Applescript Editor and paste an innocent icon on it. We liked to use the ClarisWorks icon to be extra mean.

Another variant was useful on computers that were proteted with OnGuard or AtEase. Simply make a script that would pop up a dialog box asking for the password. An unknowning teacher would enter the password and the script would exit... leaving behind a log file with the password in it for later use.

Nothing magical about these. Very basic trojan horses.

Consider the source...

Come on. MacOSRumors.com on a forum post. Let's not loose our heads and start spreading FUD because of something someone's brother's first cousins next-door neighbor read in a forum post. If you're smart enough not to accept random files and put your admin password in for anything that pops up - this won't be much of an issue.

10.5 Screenshots?!

Where? I want to see!

Further

In all the latest releases of OS X, the user will also receive the prompt "You are running for the first time. Are you sure you want to continue?" so that's *four* levels of security the user would have to specifically circumvent to be affected. At some point the responsibility has to reasonably be shifted from Apple to the user... -Kurt

I Like The Trojan Horse That Was Used

The first Mac virus hidden cleverly inside a picture of desktop eyecandy. No doubt it will spread like wildfire. Insidious.

What wrapper will the first Linux widespread virus take? "Hey, download this PDF -- it's a transcript of a big IRC shouting match about which is better, emacs or vi! You gotta read this!"

We won't know what hit us...

Need a Universal Binary

Anyone know when the Universal Binary will be avaliable? Plus, we need a "no password" crack.

When will Mac viruses get to the level of Windows when? For godsakes, this one still requires user intervention, and it doesn't even work on all OS X platforms!

Come on Apple! Microsoft has you soundly beaten in this regard :(

There is some good news in all this

It means at least one person at Microsoft still knows how to code.

The vulnerability isn't always plugged in

Everybody seems so certain that this is a non-starter on OSX because it requires some user intervention to propagate. I have bad news for you: there are clueless Mac users out there, too. These are probably the same folks who will click on a web popup to "see the lastest hollywood gaff" and then "accept" the untrusted executable when windows warns about the download to be executed. And they're the same ones who will dutifully click their bank url in an email and login to make sure their information is correct .

Never understimate the power of the incomptenece of 20% of your userbase.

Re:The vulnerability isn't always plugged in

That's why we don't consider it a vulnerability. There is no way to "fix" this without totally locking out the user.

There is no way to compensate for an Administator who is computer illiterate. It's simply not possible. You can lower the bar as much as you like, however, there is a certain minimum level of knowledge which is required to safely administer a computer.

Like don't run every application you get your hand on. This is similar to don't delete all your files.

You can't man a .app look like a .jpg in OS X

I tried to create an application that had a name of test.jpg.app and was pleased to find that, at least in Mac OS X 10.4.5, when you try to do this, the Finder displays the entire name, including the entire extension ".jpg.app", even though normally the ".app" portion is hidden. Take out the ".jpg" and the ".app" goes missing again. The "hide extension" option in the get info window is disabled when you have a name like ".jpg.app". So, it isn't quite so easy to disguise an application as a jpeg in Mac OS X. Of course not everyone is going to know what the .app means and so it being visible won't help them. Then again, if that's the case, they probably don't know what the .jpg means either!

I also tried doing this with a .term file, which was set to hide the extension. When I made the name test.jpg.term, the full name was displayed including ".term", and the "hide extension" option was disabled.

Let me get this straight...

If I write:

#include
main()
{
        (void) printf("Hello World\n");
        return (0);
}

and also included a couple lines to 'rm -rf /User/Home'....

Then I e-mailed or IM'd a person the executable, then asked them to decompress it, double-click on it, and laugh, that would be Mac OS X's first virus/trojan? Ohh wait, I need to associate a pretty icon to it too.....

As much as this author would like to claim they are the first, I think the programmers at Apple were the first ones to do this with their "Disk Utility" that a user has to click on to 'newfs' or your Windows users 'format' your hard drive.

I can not believe this made Slashdot....

Five stages of grief

I think this is a bit overblown. It sounds like a Trojan Horse, not a virus. But the originally posted messages are kind of funny. Has anyone else noticed that if you look throughout the Mac OS Rumors threads, you can find examples that follow the five stages of grief [wikipedia.org]?

1. Denial and isolation

Is this another non story just so we can toss a non story at people who argue that a Mac will be just as crap as windows given time and enough crazy automation in our email clients?

2. Anger

Oh God, shut up. The fact that you worked at an Apple Store means nothing, get over yourself. "At least a dozen people" HAHA yeah OK, you want to tell me you didn't pull that completely out of your butt?

3. Bargaining

if anyone thinks that they can isolate it and reverse engineer it or anything like that i will be happy to give you the mirrored link

4. Depression

that is seriously depressing. i am officially shaken from my nice little warm fuzzy macintosh lull.

5. Acceptance

We all knew this day would come.
It's ok, although some of you are a bit shocked, this thing was eventually going to happen. I just hope that Apple will help stop these kinds of things from happening. Safari already tells us when we download a program, and even an .exe, maybe Apple just has to add what Safari looks for when we download it. That would hopefully prevent this from ever happening again.

I think with the appropriate counseling, the MacOSRumors.com community will be just fine.

Just finished my new OSX Virus.

#!/bin/sh rm -rf /

The brilliance of shipping iPhoto with new Macs

I just realized how amrt it is of Apple to ship iPhoto with new consumer macs.

See, if a trojoan like this comes along with something unpleasant really novice users will try to move it into iPhoto - which will just say "sorry, that's not an image".

More advanced users that would just try and open an image in Preview would say "Opening an image file and it asks for my password? No thank you sir!".

Which is why this trojan has not really spread, or really affected many computers.

Re:Hehehe

There is a Mac God?

They've got one coming out in six months, it's called the iGod.

Nah, that's just the title of Steve Jobs upcoming self-biography.