Safari "Carpet Bomb" Attack Code Released

snydeq writes "A hacker has posted attack code that exploits critical flaws in the Safari and Internet Explorer Web browsers. The source code can be used to run unauthorized software on a victim's machine, and could be used by criminals in Web-based computer attacks, security experts say. The public example of the attack code allows attackers to litter a victim's desktop with executable files, an attack known as 'carpet bombing.' In combination with bugs in Windows and Internet Explorer, attackers can run unauthorized software on a victim's computer."

Comments

Re:Secure from the ground up!

[spud603]

RTFA. Actually, it looks like this is a windows problem. Safari automatically downloads a file to the desktop. Then when you start Internet Explorer it runs the file on your desktop and there is the problem.
So the real issue is that Safari can be told to automatically download a file while internet explorer will automatically run a malicious dll from the desktop. actual post and proof-of-concept code here.
seems like a misleading summary to me.

Wrong section, eds!

[himself]

This is a _Windows_ Safari problem, not an _OS X_ Safari problem. And yes I RTFBlogPost.

Re:Wrong section, eds!

[Qwerpafw]

It's a Windows Internet Explorer problem, not a Mac OS X Safari problem.

the "bug" is that Safari has the users desktop as the default download directory, and will automatically download files if you go to some websites. This is normal and fine behavior. The problem is that Internet Explorer loads files from the desktop on launch, which means if you craft a malicious library and put it on the desktop Internet Explorer will happily load it.

Microsoft should fix IE to avoid loading files from the Desktop.

Re:Wrong section, eds!

[Chas]

No. It's a problem with Windows Internet Explorer that's exacerbated by a problem with Windows Safari.

Safari should NOT be auto-dumping files onto the Windows desktop. PERIOD.

There's enough blame to go around everywhere.

Re:Wrong section, eds!

[ClassMyAss]

Safari should NOT be auto-dumping files onto the Windows desktop. PERIOD.

Totally agreed. I'd go further - no website should be able to trigger any action on my computer that persists after I close the damn browser window without my explicit permission, apart from saving cookies and leaving an entry in my history log (even then, only if I've enabled both of these things).

That said, IE is worse here - downloading files without my permission is bad form, but a pre-installed system app loading DLLs from any old place that it finds them, especially one of the most common places to dump downloaded files, is just idiotic.

Shame on all.

Quick Workaround...

[Manip]

Here are two very quick temp' workarounds for the issue.

1) Launch IE from a location other than your desktop (e.g. Start Menu, Quick Launch Tray).

2) Go to Program Files\Internet Explorer, Create Shortcut, and then place that shortcut on your desktop. Make sure the "Start In" setting is set to any location other than your Desktop.

Re:Secure from the ground up!

[Colonel Korn]

RTFA. Actually, it looks like this is a windows problem. Safari automatically downloads a file to the desktop. Then when you start Internet Explorer it runs the file on your desktop and there is the problem.
So the real issue is that Safari can be told to automatically download a file while internet explorer will automatically run a malicious dll from the desktop. actual post and proof-of-concept code here.
seems like a misleading summary to me. IE won't run anything "automatically." It sounds like the problem is that Safari both autodownloads to the desktop and then tells IE to open that file on its next load.

Re:Secure from the ground up!

[bluelip]

IE will load its DLLs automatically. If the current PATH contains the DLL, IE will use that version instead of the system version.

Re:Secure from the ground up!

[spud603]

from TFA:

The problem originated from an error that Windows Internet Explorer will load some program library files(DLL) from user's Desktop instead of its own library file folder(usually C:\WINDOWS\SYSTEM32). Apple's Safari for Windows downloads and saves requested file to user's Desktop by default - this default behavior itself does not constitute a mistake.
The 'workarounds' suggested by MS include "Change the download location of content in Safari to a newly created directory". I don't actually know what's going on with this, but it seems like it's IE opening an improperly-named (or maybe there's some bad meta-data that comes along with it?) file from the desktop, no matter how it got there.

Re:Secure from the ground up!

[Richard_at_work]

Read Slashdot: Microsoft Urges Windows Users To Shun Safari - it explains what happens in more detail.

Basically, on Windows Safari automatically downloads files, in imitation of its behavior on OSX, but whereas on OSX it downloads them to a nice ~/Downloads directory on Windows it downloads them to the desktop. Also, on OSX Safari tags the downloaded file as 'unsafe', but it fails to use the Windows functionality to do the same on Windows. This leaves a whole load of files that you never asked for or wanted lying around on your computer in a state that is one step away from being executed.

This 'attack' allows a malicious person to force Safari to dump thousands of files on your desktop, which in and of itself is not a nice thing, but when coupled with other exploits it can lead to code execution of these files you never wanted in the first place - whether those exploits are patched by the vendor (Microsoft) or not, we both know that a significant portion of desktops are not kept fully up-to-date with security releases.

Re:Secure from the ground up!

[FatMacDaddy]

You know, this is pretty clearly explained in the article. To quote: "Microsoft's advisory says that the vulnerability has to do with the way Windows handles desktop executables and recommends that Windows users "restrict use of Safari as a Web browser until an appropriate update is available from Microsoft and/or Apple."

So yes, IE is in fact autoloading executables from the desktop. It's Safari's vulnerability to carpet bombing that sets the stage, but it's IE and Windows that cause the big boom.

There is one

[Titoxd]

If Windows has an "unsafe" flag for files, it should be used by Safari. Windows has it. It's the Attachment Execution Service, located in the Alternate Data Streams in NTFS.

Re:Closest resources first

[deke_kun]

This is exactly what is happening.

And yet this is listed as a Safari flaw?

Come on, how insanely insecure is it to run executable code from the desktop! Hasn't windows had protection on the windows and system32 directories for about 6 billion years now for this very reason? And then they go and make it pull executable code from just about the least secure place on any PC.

From where I'm sitting this is a massively Microsoft problem, but their suggested "fix" is still the easiest solution by far. But its a bandaid to a gaping oversight.

Safari on the mac defaults to /Users/user/Downloads. Wouldn't be hard to change WinSafari to do the same, but it would almost be an admission of fault to all the IE fanboys.

Yup!

[nobodyman]

It would be easy enough to test this out though. manually download this DLL using IE (which marks the file as unsafe), then fire up IE7.

I tried it out: the exploit still works when you manually download the file using IE instead of Safari. So either IE isn't marking downloaded executables as unsafe either, or IE ignores this flag when loading DLL's. Either way it undermines the"Apple is at fault" argument.

Carpet bombing is still an issue, if for no reason than it is an annoyance.