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MSN, Word Vulnerable To Shell: URI Exploit
LnxAddct writes "InfoWorld is reporting that a few Microsoft products are also vulnerable to the "shell:" scheme vulnerability found in Mozilla last week. These applications include Microsoft Word and MSN Messenger."
Well at least Mozilla will fix theirs...
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Well now, let's see how long it takes for their patch to come out.
Anyone know if Word 2004 for OSX is safe from the URI exploit? I know that the macs have been having trouble with the URI exploit over the past few months based on some articles I've read at macslash.
Aj
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artlu.net
The article is short on details. Does this really work on xp sp2? I know that xp sp2 protected against the Mozilla exploit, so I would imagine the same is true here. Which would make your claim that these sorts of things are only fixed "in the open source world" seem pretty specious.
I'd rather be lucky than good.
If it's non-obvious and contrived, is it reasonable to assume that Microsoft could be lifting, or at least peeking at, code from the mozilla project and replicating it in their own browser?
Naw; if that were true, IE wouldn't suck so much.
I just tried it in Microsoft Word 2002, with XP SP1 and all of the approved hotfixes for my agency, and it restricted it just fine- wouldn't even recognize it as a hotlink.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
According to the article "Malicious hackers could launch programs associated with specific extensions using links embedded in Word documents or instant messages sent using MSN. However, the vulnerability does not allow attackers to pass instructions to the programs..." Now call me crazy, and I know i'll probably piss off the microsoft hating people here, but what harm is there really? What's some "hacker" gonna do, open up Acdsee and show my porn collection to well...me? Maybe pop open a few dozen IE windows or programs to force me to reboot? If there's nothing else being transferred it's really just more of a nuisance than something major. Or am I just reading this wrong?
By the time the Mozilla story was posted on Slashdot the fix was already available - the link was even posted with the story.
I don't see a patch posted with this story so I guess there's no way Microsoft can win the patch-speed race for this bug - all we will be able to do is place bets on just how much slower Microsoft is. Predictions, anyone?
~~~~~~~
"You are not remembered for doing what is expected of you." - Atul Chitnis
(Score: -1, Troll)
I find it interesting how they talk about "no exposure to malicious attackers", as if their products are magically invulnerable until someone discloses the hole to the public.
Oh good, I'll go and download SP2 then... What's that? It's been delayed to mid-August? Oh dear!
The URI exploit in its general form is mitigated by the fact that you can't pass any command-line arguments to the command. So you can launch a bunch of Notepads, so what? However, you CAN type a filename in and have it open in its associated application. If that filename is too long, you can exploit a buffer overflow in the helper application. There happens to be a plentitude of client applications on a standard XP box with buffer overflow possibilities. Once you're there, go anywhere you want with the privileges of the user on the XP box (which is usually admin, and if not, you can usually get admin without a lot of effort).
Anyway, SP2's memory protection would have prevented the overflow attack. It would not have prevented the most general (and less harmful) form of the attack, however.
What the original poster was probably meaning, if he had a point at all, was that non-Windows systems don't do this sort of "command-line-as-a-protocol" bullshit because it's quite obviously the wrong way to do things. Security through obscurity works in a lot of cases because people think "nobody would EVER design an OS that did THIS" and they never bother to look. Well, now someone's looked and found an ancient kludge coded by someone who probably doesn't even work for MS anymore. And more man-hours are going into fixing this bug than would have gone into creating a proper implementation of whatever this goober was trying to accomplish in the first place.
That said, Open Source isn't pixie dust that makes everything happy and secure. Stupid things happen in Linux. They just happen in the open where people can find them and fix them before applications start relying on them to function.
I think the handling of this problem demonstrates the difference between Microsoft software and other software like Mozilla. In Mozilla, the problem didn't even require a real patch to fix, just a quick config setting to tell it not to pass things along to the shell: handler. My bet is that fixing Word etc. will require not just multiple registry changes but actual new code to allow shell: to be disabled. And odds on the first thing they try is to just add filters, and we'll see half a dozen iterations of exploits of this using different ways past the filters until MS finally includes a patch to allow it to be disabled.
Actually, it was their source that was the root of the problem in the first place. The whole "shell" thing is only in windows, unfortunately the article titles lead people to believe that it is a problem with Mozilla across all platforms, when in reality it only affects those running on a Windows platform.
(that subject is a great way to get modded down)
I created a shell link inside Office Word 2003 and when I clicked it I was warned that the hyperlink contained a potentially dangerous target and that I should only proceed if I trusted the source of the document. This warning does not appear for http, https, ftp, or other common "safe" protocols.
I do not have MSN available for testing.
http://brandonbloom.name
While bug 250180 is pretty new, bug 163767 is ancient (08-2002) and describes the same problem, although being a bit more generic. I wouldnt shout too loud about fast bugfixing in OSS in this particular case. Although the bug is more a bug of Windows broken-by-design handling of URIs it still should have been fixed (or the features needed for the bug to work should have been disabled by default.)
I'm the one who posted this message to Full Disclosure. I was too lazy to test all popular e-mail clients, IM clients, word processors, etc. that run on Windows, so I posted after finding only two vulnerable programs. Who wants to help?
All you have to do is see if your programs accept links to shell:windows\notepad.exe. If clicking the link launches Notepad, it's vulnerable. If there's a warning dialog, it's somewhat vulnerable, depending on the wording of the dialog.
The shareholder is always right.
Good. Go download it. Or don't. But at least don't be a hypocrite like half the people here and say that sp2 "doesn't count" until it reaches final release form, while firefox "counts" even though it's also in pre-release form (not even at 1.0 yet). Sort of like when people claim that IE on xp doesn't have popup blocking but firefox does.
I'd rather be lucky than good.
As the University of Rhode Island (URI) University College Representative in the Student Senate, I can assure you that no student at the University of Rhode Island is exploiting Microsoft Word... we're only pirating it.....
The Article's title is: Microsoft products also vulnerable to Mozilla flaw That is gross misinfomation, it should be something along the lines of "Microsoft products allow exploit of OS flaw, similar to Mozilla." The flaw itself is in the Windows operating system. It exposes access to shell functions that applications need to blacklist. Application developers shouldn't need to be concerned with "Oh, I need to stop that protocol for security." It should be the protocol developer's responsibility to say "Is this safe?"
Yet another signature that refers to itself. The irony and humor is dead.
Microsoft Word 2003 w/Latest Updates.
Insert > Hyperlink
shell:explorer.exe (path should be unneccessary, tried shell:windows\explorer.exe as well)
Critical Error Dialog pops up
Opening "shell:explorer.exe"
Hyperlinks can be harmful to your computer and data. To protect your computer, click only those hyperlinks from trusted sources. Do you want to continue?
Yes | No
Pressed Yes and nothing to happened.
The title is quite misleading on first glance.
"Microsoft products also vulnerable to Mozilla flaw"
If it was a Mozilla flaw to start with, my linux boxes would be vulnerable. I know its picky, but the title is not accurate IMHO as Mozilla is being used to take advantage of a Windows feature, rather than the flaw itself existing in Mozilla.
It seems logical that the solution to many of these browser exploits is to run the browser with a separate set of OS permissions, i.e. as a separate user. This could be done using setuid under Unix. I don't know how it's accomplished on Windows.
The special user would have greatly reduced permissions, which would prevent these exploits from being useful. This user could not execute anything but designated plugins, and could not save files except to a designated area.
Why has this not been tried?
To try out open source browsers like Firefox and Mozilla....
;)
;)
Maybe its about time for some people to concider some alternate producivity suites - not just openoffice - even some suites like Corel have some intriguing software that lacks the user base of microsoft.
Rant>./rant
On a sidenote.. Corel lost a big share of its market to MS Office around the same time Netscape was crushed by IE. I remember my highschool used Corel at the time. Netscape was very smart to start the Mozilla Foundation insead of trying to beat MS, they are letting their supporters promote for them, gaining them some brand awareness if nothing else. Perhaps It wouldn't be so strange if Corel was to support a open source initiative, or merge with OpenOffice. The next best thing since frozen coffee for the computer geeks would be firefox and corel. Corel could sure use some geek to geek praising around now
For those of you not very firmiliar with Corel, at one point they were doing fairly well, then they kinda fell thru - had to lay off alot of people and are now trying to get back into the market.. but I personally think they face the same fate as Netscape.
In the real world, If you loose a customer, it takes twice as long to get that customer to come back to your business, and that customer is a big factor keeping other possible business from you, as they will tell at least 10 people of their experiance.
Based on this, even old Corel users would be hesitant or unwilling to switch back to Corel -so Corel needs a new movement. Open source anyone
Dying Proprietary Software + Open Source = Improved Code + Brand Awareness + "PROFIT" (Donations, Memberships? Support? and Smart Usage Of Your Brand Recognition)
With so many software companies expected to bust with news of the markets this week, I wouldn't be surprised to see a few new related open source projects pop up.
Rant> logout
Mod me down im a newf (wiki)
Okay, I'll bite. Some of us have a standard of stability and completeness, totally independent of version numbers. Was Internet Explorer 1.0 a happy, complete, stable application? Is Firefox 0.9.1? I think you're fooling yourself if you think version numbers provide any sort of yardstick of the readiness-to-use of an application. I personally won't use ANY Microsoft product in a production (read: at work) environment until it has at least TWO service packs. Windows, Office, SQL, SMS, doesn't matter. Microsoft's standard is "it's 1.0 when we need to release it. it's sp2 when it's ready for prime time". Not all companies are the same way. Corel has yet to release a product ready for prime time, and WordPerfect's up to 12 or so. Cisco, when motivated, can get things done right in the first release. Open Source projects all have their own standards. Firefox 0.9.1 is much more mature and ready for prime-time than the latest PR or SP2. The Xine maintainers, who must all be insane,
have a project that's been stable for years and it hasn't hit 1.0 yet. If Firefox suddenly released 2.0 would it sudenly be more mature? How about 3.0? What's the magic happy number? THERE IS NONE. You have to gauge each vendor, and each application, by a consistent set of rules and just forget what version number the marketing people decided it should have.
Here'show it works:
You predict the next security flaw,exploit etc etc etc and what product it will hit. Apache buffer overflow (smart money says don't pick that one), Word vulernability etc. This could be cool.
Dibs on Wednesday IE exploit.
I boycott signatures
The Xine maintainers, who must all be insane,
have a project that's been stable for years and it hasn't hit 1.0 yet.
It's worth noting that, technically, Emacs hasn't gone 1.0 yet either. The version is really 0.21 - it's just that they've been in the minor version numbers for so long now nobody refers to it that way anymore. Is Emacs incomplete? Lacking functionality perhaps? Apparently yes.
Jedidiah.
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There is a big difference between the degree of risk I take with upgrading Firefox and the major overhaul that SP2 is going to turn out being. Sorry but this hypocrite isn't buying your assertion.
I don't want knowledge. I want certainty. - Law, David Bowie
Um, well, the difference here, my friend, is that one is an upgrade for an application (Mozilla Firefox), and the other is an upgrade for an entire operating system (Windows XP). One risks the ability to browse , the other risks the ability to boot .
Prudent people might be willing to risk blowing up their pre-release browser for functionality and security, while not be willing to risk blowing up their entire OS with a pre-release patch just to get their browser updated...
emacs will hit version 1.0 when it can shake the programmer's hand, look him in the eye and say "I'm ready."
I suspect a great many apps have (until recently) just blithely passed commands that have user input into ShellExecute(). Obviously, you can't do that, a fairly clever user can figure out how to get someone else to run a command on their system without their explicit consent. Note that MSDN doesn't mention anything about the possible security implications of it, which is why MS is being blindsided by it. Now, a ton of apps use ShellExecute(), it is the recommended way to launch the correct web browser on a user's system. What I did in my app was before calling ShellExecute(), extract the protocol and compare it against a whitelist of allowed protocols. In my case, I only allowed http, https, mailto, and ftp. If it wasn't one of those four, I just didn't do anything.
to *bash* Microsoft yet again. The article clearly stated that
.....
Microsoft's MSN Messenger and Word word processing application both support a feature that could give remote users access to functions that could be used launch applications on Windows computers,
Unless the SECUNIA people are stupid, launching an app from within another app is what every Microsoft Application is able to do and has been able to do for many years. However I do not think that such feature exists for Microsoft products only. What I am having a hard time distingushing is between Secunia trying to stay on the news and a real vulnerability here. I am not saying it might not exist, but as of this moment I do not see anyone able to run a Shell() command within your app, unless they have gotten to your app, which means they have gotten to your computer already. Also this has existed for a long time. Why now? I might be completely wrong however, and someone at Secunia knows something they are not sharing. I advise them to share any info as soon as possible. The reason I am a little pissed is because in my company I have thousands of Word and Excel documents with thousands of lines of VBA code. With news like this, I smell a panic meeting early in the morning tomorrow which might be nothing more than FUD from Secunia. Honestly I am at a point where I am having a hard time trusting anyone anymore. Hackers want to be my security gurus, OS makers rant and rave about their respective OSes and how secure and reliable they are(only to issue security patches soon after), whole campaigns asking people to boycot a product because of vulnerabilities and use X product, only to find out that X is vulnerable as well. If you look at the stack of firewalls and security appliances at my company, it looks like we're building the walls of damn Troy. I joke with the security guys about the kind of attack they are preparing against. There is hope of course.....but how long before it's too late?
The phaomnneil pweor of the hmuan mnid. Fcuknig amzanig eh!
I'm going to agree with you.
This is not a flaw in Mozilla, nor is it a flaw in IE, Outlook, Word, or any other part of Microsoft Office.
This flaw is a flaw in Windows, and is typical of flaws in Windows in that the OS is expecting it's applications to handle security, will run any peice of crap handed to it by any app, and we can expect to see more flaws that are similar in nature due to the heavily integrated design of the Windows operating system.
Read, L
At school the command prompt is disabled, and you can't right click and make a new batch file, and you can't rename the extensions so in order to run some commands all you have to do is write them in notepad, and then tell it save as "all files" and then give it the .bat extension.
We sure did have a lot of fun with the netsends :P until someone put it in a loop and the teacher found out.
That's becaues it's NOT a bug in mozilla, it's a massive security hole in Windows. Mozilla finally decided to patch it for mozilla because MS was too damned lazy to fix it. As we now see, this massive windows hole affects other products too. Of course, NO other platform has this particular security hole (surprise surprise...)
If your flash plugin had a security hole, would you expect Mozilla, Opera, IE, etc to filter certain access so that security hole could't be exploited?
No, MS is responsible for the security of their own products.
The bug I submitted was marked as "Major" due to the security implications. I submitted it in early Nov. of last year. After 24 days of finger pointing and name calling towards Redmond, someone finally admitted it's a bug. The problem still isn't fixed. It gets the occasional comment and that's about it.
Finger pointing? Name calling towards Redmond? You are _severely_ misrepresenting this bug.
(to those curious: please read the bug info for yourself!)
I'm sorry, but if it takes 24 days to get past the name calling when confronted with a security flaw deemed major, OSS doesn't stand a chance.
I'd maybe lend more credibility to your statement if you weren't the bug submitter (and thus very biased). It might be major to you, but few people will be affected by this problem because a) not many people use compressed drives and b) not everyone runs windows. Don't expect people to run over and pat you on the back for finding a bug. If you think getting bugs fixed in a proprietary software company is always straightforward, then I wonder if you have experience working for a proprietary software company.
OTOH if it is very important to you or your company that this bug is fixed, why not pay someone to fix it?
No. It's saying "I have a URI I don't know what to do with." This is how non-http URI's work to launch external views such as real player with RTSP:// and such.
Creating a URI handler to execute shell commands is boneheaded. The Mozilla guys knew this but MS failed to fix it. And now we have more MS apps that don't work around this stupid thing. Any guess as to how much other software doesn't block access to this massive windows security hole?
About the only thing the Mozilla team did wrong is underestimate the stupidity of MS.
I don't have WINE installed on my system, or the time to install and configure it, but since WINE re-implements the Windows API, wouldn't it have the function that Mozilla/IE/Word call to execute shell: URLs? Has anybody tested this vulnerability in WINE? Does anybody care what the results are?
Ian
Uh, I've been doing it for IE and MSN Messenger for the past few weeks - since I was forced to switch from W2K to Windows XP at work.
/savecred /env /user:veryrestricteduser "C:\Program Files\Internet Explorer\IEXPLORE.EXE"
/env (use current user's environment) what you need to do is allow the restricted user write access to your IE required directories- e.g. Favorites, Cookies, Local Settings.
/env and run IE in the veryrestricteduser's environment and allow your normal user read access (and probably write access) to the veryrestricteduser's environment/profile. Then you don't have to allow the veryrestricteduser access to your normal user's directories. The more finely grained ACLs on Windows NTFS could make certain things more convenient.
/savecred on Win2K, so you need to enter the password everytime you launch the shortcut for Win2K or WinXP Home. Savecred works on WinXP Pro.
Create a user called veryrestricteduser and put it in a new morerestricted group and remove it from the Users group. I made the filesystem permissions more restrictive for members of that morerestricted group - so they can't even list files in c:\ only traverse it.
My shortcut for IE is:
C:\WINDOWS\system32\runas.exe
Because of the
Alternatively you could remove the
The latter method is probably safer, but doesn't allow you to share Favorites and Cookies when you do want to browse as your normal user for whatever reason.
You'll probably want to change the icon back to one of the IE icons.
The runas thing is klunkier than setuid and you can't do
If you don't trust other applications I think you can do a similar things with them. For stuff that you really cannot trust, you should run them on a VMware VM or a separate machine.
It's nothing to do with the browser. Read the bug report. Find and read the relevant MSDN article, if you like. It is not even a bug in Windows. Windows does not pass the security information between partitions.
The browser checks to see if it knows what to do with it, generally if it does, it blindly passes it to another application (plugin or whathaveyou), if not it blindly passes it to the OS which may or may not have a handler for that type.
First there shouldn't even be a shell uri in the OS! Second, there is a vulnerability IN THE SHELL URI which escalates the priv level to that of the user.
If Mozilla passed the data along and said, here ya go it's good stuff, completely trusted. That would be one thing, but mozilla passes it along and says I have no clue what this is or where it's coming from and have no reason to believe it safe in any fashion. You have any ideas?
If it's the RIGHT data, then windows tells itself it was the current user and not some untrusted guy off the web who gave it that data. The bug is in windows!
Hell the entire scheme or uri handling in windows is fscked up. There shouldn't be any uris which cause local execution!