WMF Vulnerability is an Intentional Backdoor?

An anonymous reader writes "Steve Gibson alleges that the WMF vulnerability in Windows was neither a bug, nor a feature designed without security in mind, but was actually an intentionally placed backdoor. In a more detailed explanation, Gibson explains that the way SetAbortProc works in metafiles does not bear even the slightest resemblance to the way it works when used by a program while printing. Based on the information presented, it really does look like an intentional backdoor." There's a transcript available of the 'Security Now!' podcast where Gibson discusses this.

Comments

I would not be suprised at all.

[AltGrendel]

I could see someone deliberatly doing this, maybe a contractor or a disgruntled employee.

Its happened before and it will happen again. Whether this is the case remains to be seen.

Re:I would not be suprised at all.

[NtroP]

I could see someone deliberatly doing this, maybe a contractor or a disgruntled employee.

The problem with that argument is that in order to exploit this backdoor you'd have to get the target computer to load a WMF file. The main practical way to do this would be to embed it in a web page and have the target visit that page. The only sites that all windows machines access on a regular basis are Microsoft's. The employee would also have to have access to Microsoft's web site to exploit this reliably.

This seems to be only useful if MS itself wanted to use it. Use your imagination as to what they'd do with it. I can think of all kinds of things.

Re:I would not be suprised at all.

[dc29A]

I could see someone deliberatly doing this, maybe a contractor or a disgruntled employee.
- How about a totally stupid idea that MS thought was good?

I mean MS has a long history of ignoring security for usability, lock in and whatnot. WMF dates back to close to 10 years, back when MS really didn't give a damn about security. Even after a the big Gates propaganda email and Trusted Computing Initiative and all the hoopla, XP SP2 allows blank passwords for administrators, the user created during installation is an administrator, again if password is blank no one gives a shit. Remote registry is on by default. RPC on by default. Administrative shares are on by default. Not to mention a plethora of completely useless services.

MS just doesn't understand security. This WMF example is nothing different. It's some ancient code that never got looked at. Add to that the fact everyone and his mother is root, AND that the OS is a big bowl of spaghetti (hi2u IE deep in kernel), you get another attack vector vs Windows systems.

Did someone maliciously implement this WMF "feature"? I doubt it. It looks like another regular MS security hole that shows that MS has no clue about security.

Re:I would not be suprised at all.

[Stripe7]

Someone mentioned on Groklaw that the exploit also exists in wine which just implements the WMF spec.

Re:I would not be suprised at all.

[monkeydo]

Actually, Gibson is saying he doesn't know if previous versions are exploitable or not. In fact he's counting on not, since that's the only way to determine when the "backdoor" was inserted. Gibson is a bomb thrower. There's no evidence other than his opinion that this is a deliberate backdoor.

Re:I would not be suprised at all.

[QuietLagoon]

The only sites that all windows machines access on a regular basis are Microsoft's.

I presume you are willing to show the details of your extensive research that determined this factoid....

Re:I would not be suprised at all.

[Reziac]

Not only that, but my understanding is that the relevant WMF functions date back to the Win3.0 era (maybe Win2.0, not sure -- the earliest date I've seen was 1991) and in any event, long before M$ had much of a clue about the internet. And long before OS "back doors" became a common worry, too. M$ simply doesn't plan that well when it comes to how stuff is used/affected by an OS, and in fact tends to come late to the bandwagon.

Furthermore, if Gibson is so sure of himself, why isn't his own test utility available to everyone? (Apparently it was only available to Laporte's listeners... not likely to be the most unbiased audience.)

Net result: I knew Gibson's tinfoil hat was a trifle snug, but now I'm sure it needs a complete refitting.

Re:I would not be suprised at all.

[mohaine]

I thought this as well, but if you RTFA, you would see that Gibson doesn't think the SetAbortProc WMF exploit works the way it should.

According to the docs, SetAbortProc should provide a pointer to callback function that is called when a print is aborted. This in itself sounds like a security hole, but it could only be fired if the print is canceled, and then it can only run a preexisting callback method, not arbitary code.

According to Gibson, if you call SetAbortProc with a special key, it will instantly start running arbitary code from within the WMF. No cancelled print or preexisting method calls are requried.

If Gibson is correct, this bug is much different then how it looks on the surface.

Re:I would not be suprised at all.

[azuretek]

Most Windows computers at one point have connected to Windows Update, also IE defaults to MSN, isn't there a getting started page as well when you first open IE after install?

It's just simple observation to say that the only site that would be consistent on every Windows system is a Microsoft site, somewhat how on my mac I am connected to apple after a clean install when I open Safari. One could say the only site that would be consistent on every mac would be apple.com.

-PS I don't think it was an intentional backdoor.

Re:I would not be suprised at all.

[jez9999]

Furthermore, if Gibson is so sure of himself, why isn't his own test utility available to everyone?

Eh? I just downloaded it, it's linked to from here.

Re:I would not be suprised at all.

[mrseigen]

I'm not quite sure why they'd want to use it. End-users already trust Microsoft implicitly because they made the operating system, so if they wanted to, for instance, install some software on all Windows machines that reports home if it detects a pirated copy, they could just do it through a service pack update. Most people would willingly install it (or click the little automatic button in Windows Update), and there'd be none of this Tom Clancy technothriller intrigue.

I can't personally think of any kind of official reason why Microsoft would want to shove code onto Windows machines just from visiting their website. They've got tons of other ways of doing this.

NSA

[Anonymous Coward]

Well, how else is the NSA going to fight terrorism?

Government backdoor?

[Jerry_Duplicate]

There was talk about the NSA/CIA having a close relationship with Microsoft and being able to exploit backdoors in Windows. This could have all been conspiracy theories, but the fact that this vulnerability existed throughout the Windows line kinda seems odd..

If this isn't a glaring example on why you should support open source, I don't know what is....

Re:Government backdoor?

[Dystopian Rebel]

but the fact that this vulnerability existed throughout the Windows line kinda seems odd.

The function in question has existed for a long time. The exploit is in Windows 2000 and more recent. From the transcript:

But the only conclusion I can draw is that there has been code from at least Windows 2000 on, and in all current versions, and even, you know, future versions, until it was discovered, which was deliberately put in there by some group, we don't know at what level or how large in Microsoft, that gave them the ability that they who knew how to get their Windows systems to silently and secretly run code contained in an image, those people would be able to do that on remotely located Windows machines...

Re:Government backdoor?

[ZorbaTHut]

Yes, because it's impossible for an identical problem to exist in WINE, and therefore open source solves all problems.

Re:Government backdoor?

[einhverfr]

The first NSA-induced backdoor that was well documented was in Windows 95/98/ME and NT4 and later. A reasonably good writeup is found at http://www.heise.de/tp/r4/artikel/5/5263/1.html (english).

Needless to say, I am not at all surprised that there might be all sorts of backdoors in Windows that we may never know about. This is a really good reason *not* to use it in any environment requiring security.

Re:Government backdoor?

[monkeydo]

Paraniod speculation. Much like the current story.

Re:Government backdoor?

[einhverfr]

First you have to understand what the ramifications of this are likely to be.

The NSA is (in theory at least) legally forbidden to spy on Americans. Their main mission involves cryptoanalysis (codebreaking) and signal intelligence. So they spend a lot of time in foreign countries evesdropping on cell phone calls and the like. They have also been very much involved in the development of computerized cryptography (witness their role in the creation of DES). In this latter case, they have probably attempted to balance their interests in codebreaking with the legitimate interests in algorythmically secure encryption (i.e. make DES algorythmically secure, but shorten the key so we can break it if we really have to).

The rise of independant professional cryptography organizations, like RSA, Inc. has created a very serious problem for the NSA in this regard. In general, most of these new systems use variable length keys and are highly peer reviewed for attack potential. So the NSA cannot count on being able to brute force decrypt a document within a reasonable timeframe in the event of a clear and present need to decrypt the information.

Therefore, I believe that most of these are there to allow the NSA to bypass the encryption algorythms in Windows and allow them to access the information without having to attack the encryption. This would make reasonable sense given the NSA history.

Now, I see *no* reason to suppose that the NSA has anything to do with the WMF exploit. Instead, I suggest that this is likely to be a backdoor either put in place by a developer, at the request of a partner (such as the RIAA), etc. This backdoor has *nothing* to do with anything the NSA typically gets involved in, so I think even the most paranoid analysis can rule them out. Instead, this is just a strange attempt to allow the Media Player to be subverted and used in what ever way an attacker decides.

Now, Microsoft's response to this has been inadequate (they only grudgingly developed a patch), which suggests that this backdoor had the blessing of the company, much like the response to the Sony DRM rootkit which was undetected by agreement with First4Internet. Lest I appear to be too hard on Microsoft, I found Symantec's response ("Oh, we will start removing it" when First4Internet claims they were working with Symantec to ensure that it would not be removed) to be far less trustworthy.

Anyway, there is enough doubt in my mind about Microsoft's goodwill on these areas that I would not suggest running Windows in any environment that absolutely requires security. The system has fundamental design flaws from a security point of view, and these problems continue to underscore either serious development issues at Microsoft or an attitude that the security of the customer is not really that important.

Re:Government backdoor?

[man_of_mr_e]

Actually, Bruce Schneier's analysis is somewhat different.

http://www.schneier.com/crypto-gram-9909.html#NSAK eyinMicrosoftCryptoAPI

The fact is, the majority of the people making claims about this don't even understand what it does. The majority of the speculation isn't possible. It doesn't give anyone (Not even Microsoft, much less the NSA) a backdoor into your computer.

Length==1

[atfrase]

This does look awfully like a special-case trigger. The idea of a backdoor is to have it look for a specifically crafted but completely nonsensical and invalid input sequence -- this serves as the "key" to the backdoor, ensuring that no other designer or user accidentally stumbles onto it. Since we assume that legitimate users and developers will only provide valid input, we design our "key" to be definitely invalid. For me, that length==1 trigger is the most convincing evidence. It's not just that it's the wrong input, it's that it's the one specific value of wrong input that triggers the behavior. That seems like design.

Re:Length==1

[stevied]

Obviously SetAbortProc should not be implemented for WMF playback, but assuming somebody screwed up and just called the normal version of Escape(), could the behaviour we're seeing here not somehow be the result of not checking the validity of the length parameter properly, performing some arithmetic on it, and possibly falling through to some other code that happens to a jump or call?

Re:Length==1

[Procyon101]

Possibly, but I doubt it's a Microsoft sanctioned backdoor. Any "OFFICIAL" backdoor from MS would have a much more complex key to get in than "1".

I can see this being a programmer supplied backdoor, like a hook for easter eggs, but based on the other security work done in MS, anything that can be gotten into that is there on purpose is locked up pretty tight to any casual attempts.

Re:Length==1

[atfrase]

Agreed, it doesn't seem like the kind of "feature" that was designed in top-secret MS design documents or developed in meetings.

But I still have a hard time seeing how code would *accidentally* behave like this. An invalid length should abort processing right off the bad, for one thing; "falling through" might be an explanation, but what possible code could be "fallen through" into that would set CPU execution *inside* the metafile -- moreover, would set CPU execution to the *next byte* after the erroneous header block. That's awfully convenient; if it were a mistake, I'd expect code execution to begin at some other random location, probably influenced by whatever happened to be in the register or some temporary pointer variable at the time. But the very next byte? That's too insanely convenient -- you get to provide your key *and* your payload in the *same* place.

You could argue that buffer overrun exploits do the same thing, but the idea of the buffer overflow is to specifically overwrite the function-return pointer to *make* it point at your code. In this case, the exploit doesn't have to specify the location of the code to execute, Windows does that for you. Too convenient.

Re:Length==1

[Shimmer]

You're right, of course. Everyone who's saying this is "obviously" intentional are jumping the gun in a big way. I've got $5 right here that says it's an accident.

"Never ascribe to malice that which is adequately explained by incompetence."

Re:Length==1

[atfrase]

Basically, in the header block for a unit of WMF script contains a "length" field which specifies how long the current unit is. This is standard for this sort of file, and is the primary way to avoid buffer overruns (if you force the data to tell you how big it's supposed to be, and then double check that while reading, you make sure you have enough buffer space to store it all -- otherwise you might read too much, overrun the end of the buffer and trash an important function pointer or something..)

In this case, the smallest possible "length" value is 6, because the header itself takes 6 bytes, so even if the unit had no actual data, the length field itself and the unit's command code is a minimum of 6 bytes.

To trigger the exploit, the length must be set to 1. Not 2, 3, 0, or some other equally invalid value, but only the value "1". Any other value has no effect at all.

Re:Length==1

[BandwidthHog]

To trigger the exploit, the length must be set to 1. Not 2, 3, 0, or some other equally invalid value, but only the value "1".

And the counting of the length shall be ONE!

Sorry, couldn’t resist.

Re:Length==1

[StarDrifter]

For me, that length==1 trigger is the most convincing evidence.

It might have been convincing if it were true. The vulnerability checker from Ilfak Guilfanov's site uses length==17 to trigger the exploit (Look in the wmfhdr.wmf file in the source zip. The length is a little-endian DWORD at offset 0x12.)

The Metasploit module uses a length of 4. Check out the following snippet:

    #
    # StandardMetaRecord - Escape()
    #
    pack('Vvv',

        # DWORD Size; /* Total size of the record in WORDs */
        4,

        # WORD Function; /* Function number (defined in WINDOWS.H) */
        int(rand(256) << 8) + 0x26,

        # WORD Parameters[]; /* Parameter values passed to function */
        9,
    ). $shellcode .

I think Steve Gibson is confused.

do you mean

[Anonymous Coward]

This Steve Gibson ?, yeah he is a real security expert, along with his podcast boy wonder we have much to be afraid of

Re:Another?

[dr_dank]

How about a link to information on the "other" intentional back doors that exist?

*looks at clipboard*

Ok Goatse linkers, thats your cue.

SetAbortProc

[jwegy]

Yeah, SetAbortProc is used for cancelling print jobs. Here is the MSDN documentation: SetAbortProc

Possible uses?

[Kitsune78]

The freakish thing about this, is that if it is indeed a backdoor, it an odd way to go about it. You can't force someone to try to view a WMF. What would its purpose be? You can't use it to get into the exact box you want to, just into a random box that perhaps picks up your WMF from a webpage, or displayed in an application.

Re:Possible uses?

[RexRhino]

Digital Rights Management... If you can control a box using a WMF file, there is all sorts of digital rights management mischieve you can do to prevent a machine from copying a file, or decoding a file, or whatever.

Lawsuit time

[Animats]

Someone involved in a WMA-related lawsuit needs to subpoena, from Microsoft, all the source code and all the change control information for this small part of Windows. Then the original programmers need to be found and deposed under oath. This is standard legal procedure for something like this.

It's possible to get to the bottom of this by legal means.

Magic Lantern?

[Tackhead]

Sometimes even a blind squirrel gets a nut.

The notion of a backdoor in Windows isn't new. Perhaps the WMF vulnerability was one of the vectors used by Magic Lantern, which was the code word for at least one of the FBI's keylogger programs. Magic Lantern was notable in that antivirus providers participated with the Feebs in a gentleman's agreement to not look for it.

It's certainly a dumb enough solution that the IT-challenged FBI might go for it.

On relative dumbness and smartness, I'd expect smart spies, namely those who work for two other notable three-letter-agencies, to use somewhat more interesting techniques. If it were me, I'd take advantage of equipment I had in place at critical infrastructure points to conduct MITM attacks between a PC and Windows Update servers, in order to transparently install my spookware on only those machines that specifically identify themselves - by means of GUID or whatever other stuff I could glean from the Windows Genuine Advantage and other DRM-related bitstreams - as belonging to my target population.

Paranoid? If you're not paranoid, you're not thinking far enough ahead.

Re:And this door leads to...

[Tebriel]

A lawsuit is not the answer to everything.

Steve Gibson is a crackpot

[Sycraft-fu]

Please remember this is the same Steve Gibson who claims to have invented a new amazing "nanoprobe" technology for port scanning which he claims is a first to the world and can do just about everything. Of course turns out to just be specially crafted TCP packets with no payload, which nmap has done since forever.

The guy is a massive alarmist and I wouldn't take anything he says seriously. He loves to cry about the end of the digital world type scenarios, perhaps because he really believes it, or perhaps because it gets him more business.

Re:Steve Gibson is a crackpot

[Moby Cock]

Normally I'd agree with you. But in this case I think he may have found something very important. This WMF flap stinks to high heaven. The fact that there seems to be a specific and deliberate key (length == 1) is very disturbing. Gibson is a wacko and doomsayer, but today he may have found something valid.

Re:Steve Gibson is a crackpot

[Rashkae]

Overlooking that Wine has innadverdantly re-created this 'back door' by following the API spec. This is all by (poor) design, no code back doors involved. Not even a bug, per say, since it's working as designed.

Re:Steve Gibson is a crackpot

[RShearman]

The Wine bug was a different bug. The SetAbortProc record specifies a pointer to a function which will be executed at a later point, and which it would be difficult to set to arbitrary code in the WMF itself, whereas this bug appears to be creating a thread which immediately runs starts executing the instruction at the next byte in the meta file.

Interesting evidence

[joshtimmons]

I agree with the author that the length prefix is something of a smoking gun. It begs the question of "how do we know it was fixed..." For example, they could change it to execute the datastream when length is set to a new trigger value; or a stronger backdoor would ignore any unsigned code. Still there, but harder to test for.

It's a straightforward way to add a backdoor that will bypass firewalls, etc. It can be triggered by a browsed page, email, etc. It's better than gif/jpeg encoding because those are more "platform independent." and the payload would be more likely noticed by a 3rd party decoder.

On the other hand, isn't this flagged as an attempt to execute code on a data page?

Also, if it were official, doesn't MS have easier ways into a general box - say through security updates, or even the entire existing code base?

Please not Gibson again...

[Anonymous Coward]

Steve Gibson is not a security expert

http://www.grcsucks.com/

Re:Please not Gibson again...

[NtroP]

Steve Gibson is not a security expert

I'm not a security expert either. But if I came up with this evidence, how would that change the reality of the situation. The evidence stands on its own merit. His reputation has nothing to do with it. This is easily verifiable by anyone with at least his level of knowledge. It will be interesting to see what happens when other "real" experts start looking at this.

What about wine?

[Meltr]

I thought the same vulnerability exists in wine?

http://it.slashdot.org/article.pl?sid=06/01/06/204 3203

Yeah...

[TheAwfulTruth]

Isn't this the same Steve Gibson that was freaking out about how Raw Sockets in XP were going to destroy the world a couple of years ago?

S.G. is a flaming idiot, he looks for (and imagines) ghosts and spooks in every corner. Then flogs his conspiracy theories to promote himself and his buisness. This probably holds about as much water as the "discovery" of cold fusion and Korean human cloning.

Why aren't we reporting on REAL bugs like the 4 security vulnerabilities found in iTunes this week which opens both Windows and Mac users to external attack? Was the Microsoft bashing quota too low this week?

What is becoming of /.?

Re:Yeah...

[NtroP]

Isn't this the same Steve Gibson that was freaking out about how Raw Sockets in XP were going to destroy the world a couple of years ago?

Didn't that get quietly fixed in a subsequent update and therefore NOT become an issue? He may be an alarmist, but he's normally a Pro-MS guy. In this case, I think he's on to something.

You're on

[Benanov]

Actually, I think Microsoft will go after Gibson's reputation.

Re:You're on

[rbochan]

Like that'd be a tough thing to do...

Re:Unparalleled BS from MS.

[Soporific]

I't a lot like the Allied soldiers who were fighting in Germany, being told all these horror stories about how evil the Nazis actually were, and then coming upon a concentration camp and finding out that these stories were real after all.

It's nothing like that actually, you are comparing apples to supernovas.

~S

Re:Another?

[gbobeck]

How about a link to information on the "other" intentional back doors that exist?

Sure fine... Behold the Power of Google!

Have Fun.

Thread Creation

[Lagged2Death]

For me, that length==1 trigger is the most convincing evidence.

I don't think it's surprising that a piece of code might behave in an odd way if it's given invalid input, i.e., if a buffer length is wrong.

I think the real giveaway here is that Windows creates a new thread when presented with this magic length. That's like rolling out the red carpet for the attacking Huns. I don't think the average buffer overflow type exploit gets it's own thread or process.

And of course it's still possible that it was all a mistake. The C language can be used to write some extremely tangled code, if one is so inclined. Something like an incorrectly used setjmp/longjmp could have effects like this.

Re:Thread Creation

[atfrase]

I don't think it's surprising that a piece of code might behave in an odd way if it's given invalid input, i.e., if a buffer length is wrong.

Again, agreed. But again, the catch is in the particular kind of odd behavior. If I were writing that code and it hit an invalid length, I'd probably abort processing of the whole file, presuming data corruption. Failing that I'd just skip over the flawed block and proceed with processing the next one. In that case, I could imagine not checking the length very carefully and just going to " + " to process the next block -- this would produce the observed "next byte" pointer.

The problem is in the semantics: I said *process* the next block, not *execute* it. If anything this would just cascade into more error cases, since the data that was expected to be the "next block" would almost definitely also have a malformed header (since it wasn't intended to be a header at all), etc.

So, I guess you're right - the tipoff is still that actual code is executed without having to be specifically pointed to (i.e. buffer overrun), and that it's executed in its own thread, rather than taking over the processing thread that was interpreting the metafile in the first place.

Re:Thread Creation

[0123456]

"it's executed in its own thread, rather than taking over the processing thread that was interpreting the metafile in the first place."

But that's only an issue if the WMF-processing code doesn't create a new thread in order to call the subroutine in the valid case. In reality you'd almost certainly want the callback to happen in its own thread, rather than to allow anyone to run abitrary code in the same thread as the print server.

Patch

[Paradise Pete]

If it were intentional you'd think they would have been able to patch it a little more quickly.

Who DOCUMENTS their evil backdoor?

[nweaver]

Who writes an evil backdoor, which dates back to Win3.1 days (when you didn't NEED an evil back door, and Windows had no clue what this Internet thing was about), and then DOCUMENTS it?

Lest we forget that Wine also proved vulnerable, and it was a clean-reimplementation of the specs!

Ah, nice Ad-Hominem attack in there...

[Spy der Mann]

The name means nothing. It's the facts that matter. Whether he is a one-day hacker or some looney, he discovered that for Length==1, (a completely invalid value that makes no sense for WMF's), Windows creates a new thread and starts executing the code.

IMHO your "debunking steve gibson" site is nothing but a smokescreen to divert the attention from Microsoft's vulnerabilities and backdoors.

Re:Ah, nice Ad-Hominem attack in there...

[undeadly]

IMHO your "debunking steve gibson" site is nothing but a smokescreen to divert the attention from Microsoft's vulnerabilities and backdoors.

In my not so humble opinion, you don't know what you are talking about. Go read some of the links in that site, and you'll see that Steve Gibson is one of the many "security experts" that have no clue but gives dangerous and very wrong "solutions".

Re:Ah, nice Ad-Hominem attack in there...

[TheNumberless]

In my not so humble opinion, you don't know what you are talking about. Go read some of the links in that site, and you'll see that Steve Gibson is one of the many "security experts" that have no clue but gives dangerous and very wrong "solutions".

In my ever-so-humble opinion you completely missed the point of the parent. The reputation, sanity, motives, and anything else dealing with the person making the claim has nothing to do with the validity of the claim itself.

In this particular instance, there is at least some apparent merit to the idea that this was an intentional backdoor, and that merit would be there regardless of who points it out.

If you want to discredit the idea that this is an intentional backdoor (of which I am far from convinced), then you should attack the argument directly, not the man making it.

Re:And this door leads to...

[Anonymous Custard]

"A lawsuit is not the answer to everything."

Since profit is all a corporation cares about, suing away those profits is the only way to punish it.

This guy is a moron.

[gregarican]

I browsed over several posts on his website and come away with the conclusion that he is a few fries short of a Happy Meal. Here's one posting that I found really amusing:

"Thank you Microsoft for blessing us with a patch to fix the products
you currently sell. The products that compete with Linux and Macintosh.
Excellent job at diverting the our attention away from the fact that
Windows 95, Windows 98, Windows 98SE, Windows Millennium Edition, and
Windows NT4 remain vulnerable. Neat trick convincing people that "the
vulnerability is not critical because an exploitable attack vector has
not been identified that would yield a Critical severity rating for
these versions."

Lemme see here. Windows 95 is 11 years old. Windows 98 is 8 years old. Windows ME is 6 years old. And Windows NT4 is 9 years old. How many other operating systems offer patches and support product versions for software that is that old?

Ridiculous.

Back door flaw?

[digitaldc]

If it is intentional, I don't see how it possibly got past the Microsoft Security Engineers.

Why hasn't he stepped into the WMF interpreter?

[criznach]

My question is this... If the guy is smart enough to know that windows has kicked off a thread and executed his code, and he's smart enough to experiment with buffer-overflow exploits, why hasn't he stepped through the WMF interpreter code? Could it be that he doesn't want to admit that he has for legal reasons? I know that if I had discovered this problem, that's just what I would do. Call DebugBreak() and you have a call stack. You'd think that the handler for this SetAbortProc function would be pretty identifiable. So... Who's got the balls (or the time, in my case) to do it? That's our answer. Chris.

Backdoor Holes

[RequiemX]

Most backdoor hole problems can be patched with the application (of) Preperation H.

Would be a Crappy Backdoor

[ErMaC]

While the guy makes some good points, there's one point I think he's overlooking. He claims motive for this would be to allow Microsoft or someone else to get into older/current Windows systems as an intentional backdoor...

If that's the case, they chose a dumb place to put it, because the exploit doesn't even work on Windows 2000 and below without some program installed to handle WMF files. From Larry Seltzer's blog (linked from F-Secure):

http://blog.ziffdavis.com/seltzer/archive/2006/01/ 03/39684.aspx

Except for Windows XP and Windows Server 2003, no Windows versions, in their default configuration, have a default association for WMF files, and none of their Paint programs or any other standard programs installed with them can read WMF files. One ironic point to conclude is that not until their most recent operating system versions did Microsoft include a default handler - the Windows Picture and Fax Viewer - for what has been, for years, an obsolete file format. And now it comes back to bite them.

That means that unless Microsoft used some OTHER backdoor to install a handler for it, this backdoor is useless. I suspect this is merely an oversight on their part, and that it just ends up looking bad when you view it from the outside. The only way to know is to see the source code and well, we know how likely that is.

A real backdoor would be something remotely exploitable via the network, as opposed to hiding inside a file or something like that.

Re:And this door leads to...

[mysticgoat]

A lawsuit is not the answer to everything.

Too true.

This is a case for criminal prosecution. Gibson has uncovered evidence that at face value demonstrates that there has been a conspiracy to defraud Windows users, and possibly to defraud Microsoft Corporation itself. Microsoft's internal documents would identify the coder(s) involved in this deceit, and possibly other conspirators.

I think it is time for the Washington State Attorney General to give this to a Grand Jury. (IANAL, but I think it is the business of a Grand Jury to determine if a crime has been committed in this kind of circumstance).

Let a Grand Jury hear this evidence and decide whether it appears that some person(s) deliberately set out to violate the privacy of Windows users.

Think about it like a programmer

[RingDev]

Code encounters escape character

exit standard processing

encounter SetAbortProc

open thread to communicate with windows print manager

thread attempts to read [length] bytes for sub value, encounters overrun

this is where I'm guessing the real horrendous problem lies. I'm guessing that the original code ignores exceptions while pulling in the sub value, so in this case where code hits an overrun, instead of that sub value getting a few bytes of data, it just graps until . In this case that sub value winds up being the payload.

So there you go, key and payload on an independent thread because of a bad exception handler in a 12 year old block of code.

-Rick

Re:Unparalleled BS from MS.

[mattbot 5000]

It's nothing like that actually, you are comparing apples to supernovas.

It's worse, actually. He's comparing security holes to concentration camps.

Re:Unparalleled BS from MS.

[jcr]

Germany, being told all these horror stories about how evil the Nazis actually were, and then coming upon a concentration camp and finding out that these stories were real after all.

The stories Allied soldiers were told about the nazis paled in comparison to what they saw in the camps. Allied propagandists didn't have the imagination to come up with anything like the holocaust.

-jcr

still in use

[Anonymous Coward]

The 98 series and NT4 are still in widespread (millions and millions) use. This is called a "problem" then. The auto industry in the US tried to pull this stunt of obsoleting and stopping support for their products in short time frames (sometimes within the SAME model year!) and got legally smacked down for it. Now they are required to provide replacement parts for ten years. Just because normal business productlaws and warranties aren't applied to software-yet, and they certainly should be-doesn't mean it wouldn't be a good idea. Planned obsolesence and forced upgrades might be a spiffy way for some corps to extract a lot more dineros from your wallet, but it doesn't mean it's a good idea for you the consumer/end user...unless you are a pure "caveat emptor" anything-goes styled capitalist. Thankfully, most people see the illogic in that sort of system and that is why we have evolved some consumer protection laws. It is not a perfect solution, but it is light years ahead of legalised snakeoil like it was before. Eventually these sorts of laws will be applied to software,because even the dullest clicker is starting to bingo to the fact that most of this forced upgrade stuff is a cash cow dodge.

Re:Another?

[monkeydo]

Actually, it's pretty well known that that isn't what happened at all.

Re:Another?

[lgw]

You mean the urban legend about an NSA backdoor? There was *never* any evidence of a backdoor, only a registry key named "NSAKEY" and a bunch of paranoid fantasy. Because, you know, if the NSA did have a secret backdoor, they'd make sure is was called NSAKEY, in case they forgot where it was, or something.

Reflections on Trusting Trust

[Mr Z]

I'm surprised nobody's trotted out Reflections on Trusting Trust, by Ken Thompson. Not only does this discuss a backdoor, but also a backdoor that can't be found by examining the source code.

But wait, there's more...

[IPFreely]

It that is all it was, then the the same thread would jump into the user code. But wait...

I found was that, when I deliberately lied about the size of this record and set the size to one and no other value, and I gave this particular byte sequence that makes no sense for a metafile, then Windows created a thread and jumped into my code, began executing my code.

So, it accidently created a new thread, and directed the new thread to start executing code at the specific position? That's a whole different level of accident.

Oh, and Shimmer, I'll take that 5$.

Sun and HP for two

[Secrity]

"Windows 95 is 11 years old. Windows 98 is 8 years old. Windows ME is 6 years old. And Windows NT4 is 9 years old. How many other operating systems offer patches and support product versions for software that is that old?"

I know of at least two. Both Sun and HP still provide support or patches for versions of UNIX System V that are older than Windows 98.

Jumping to conclusions.

[matman]

Having read the whole thing, I do think that Steve may be jumping to conclusions a bit too quickly.

I think that we ARE talking about the SETABORTPROC vuln that everyone has been talking about; Steve just finds that the vuln doesn't work quite the same way that he was expecting. It seems that Steve is basing his accusation on the fact that he had to set the length field of the code containing WMF record to 1 (an illegal value) in order to get his code to execute. While this seems odd (and sounds like a "magic value"), there is likely a better explanation. Here's one possibility... The advisory from Secunia at http://secunia.com/advisories/18255/ says that the embedded code executes when any error is detected in parsing the WMF file (not only [or ever?] when canceling printing). Maybe the SETABORTPROC function was originally intended for printing but was overloaded to handle parse error callbacks? Depending on how the parsing code was written, it may treat the invalid length value as such a parsing error, but may have already indexed the the beginning of the code block (since it knows the length of the record header) - it just doesn't know when the code block ends. It can then start executing the code block, even though it is an error in the code block's record that caused the error. I wonder if the code block would execute if the correct length was specified but the NEXT record in the WMF contained a similar error (like an invalid length field).

He may very well be correct that someone has intentionally included this mechanism as a backdoor, but he is being premature in making such claims without first consulting the people who have a lot more experience with this vuln than he does. By the way, MS gives access to their source code to a LOT of outside parties - I'm sure that Steve could have found someone to take a look for him.

I don't mean to make an ad hominem attack (this podcast is actually fairly accurate - just jumps to conclusions), but Steve isn't exactly known for being a respected researcher in the security industry - he's a bit of a poser and sensationalist/alarmist. My gut feel is that Steve is continuing on his sensationalist streak, jumping to conclusions and trying to drum up more excitement. He frequently hypes issues to crazy levels and tries to make himself look like a hero/expert. In fact, he usually offers little insight and often tries to pass off regurgitation (often inaccurate) as original research. Just listen to him in this recording talking about "rolling up his sleeves" and "wrote all my own code", etc. Look up his stuff on nano-probes (http://grc.com/np/np.htm) for some funny stuff. I am a security professional and can tell you that much of his writing is BS and/or hyped/obfuscated wording for technologies and techniques that have been in common usage for years and years before he writes about them. I just can't help but take Steve's claims with a grain of salt.

Re:blank admin password

[tpgp]

Get a clue, troll-

If you're going to accuse someone of trolling, you want to be pretty sure about your facts.

if you have a blank admin password, XP prevents ANY remote network access using that account.

Hmmmn, thats an interesting band-aid.

You are actually more secure with a blank password.

Really? More secure with a blank password? I doubt it.

Would make privilige escalation pretty damn easy after you'd hacked a user account.

And it makes all that least priviliged user stuff that MS goes on about a little irrelevant too.

Re:blank admin password

[John Newman]

Hmmmn, thats an interesting band-aid.

Must be a pretty recent band-aid, too, since I deloused an XP computer exactly one year ago that had a blank admin account password, and which had been pwned by a worm that spread precisely by trying to log into everything it could see using administrator/[blank].

Re:Wasn't it actually DES?

[Ashinberry]

Actually the changes suggested by the NSA increased the strength of DES rather than decreasing it.

http://www.schneier.com/blog/archives/2004/10/the_ legacy_of_d.html

(OT) Re:Unparalleled BS from MS.

[Tired_Blood]

The problem encountered by those reporting on the concentration camps was that in the FIRST world war, everybody got exposed to extreme propaganda depicting all germans as vile creatures. When the exaggerations and lies were brought to light, the public had then learned to seriously doubt such extreme accusations. It could be argued that when the reports from Jan Karski (an eyewitness to the ghetto and concentration camp conditions) were dismissed, it was due to that legacy of doubt in 1943.

The reporting during WWI damaged the credibility of all reporting during WWII.

jcr (53032): Allied propagandists didn't have the imagination to come up with anything like the holocaust.

They most certainly did have the imagination, but they realized that they did not have a willing audience for such accusations. Successful PR cannot be had with seemingly wild claims, especially if the organization has been shown to greatly overexaggerate in the past.

Waif

[djdavetrouble]

where you waif that right.

I really think kate moss doesn't have anything to do with this, despite the recent press tizzy.

Re:Another?

[JourneyExpertApe]

Because, you know, if the NSA did have a secret backdoor, they'd make sure is was called NSAKEY, in case they forgot where it was, or something.

Stranger things have happened. When a German law enforcement agency forced the developers of JAP (Java Anon Proxy) to put a backdoor in it, they put in code like:

if(crimeDetected) {
object->logCrime(...);
}

And it was an open-source project. Someone later admitted that they were kind of hoping that somebody would notice it, because they didn't think they could legally expose it themselves. Maybe someone at Microsoft didn't think it was right for the NSA to install a back door, and they had a conscience. Wait, what am I saying? This is Microsoft!

Plenty evidence....like the backdoor CODE!

[kupci]

here's no evidence other than his opinion

(Defending Microsoft - only on Slashdot. Ok, so some monkees tapping on a keyboard while the programmer wasn't looking snuck this code in ;)

First of all, Gibson is no bomb thrower, he's uncovered some pretty serious security issues with Microsoft. I'd suggest reading his web site - he's a very thorough person, and doesn't make any wild unsubstantiated, naive, biased claims, like, say, Slashdotters. He's a long time Windows user, not a Mac fan, nor an open-sourcer (at least until recently, for reasons like this)Now, to quote the transcript, curious where you would even be able to make the claim that that this *isn't* a backdoor:

what I found was that, when I deliberately lied about the size of this record and set the size to one and no other value, and I gave this particular byte sequence that makes no sense for a metafile, then Windows created a thread and jumped into my code, began executing my code. Okay, Leo? This was not a mistake. This is not buggy code. This was put into Windows by someone. We are never going to know who.

Yeah, he's saying this is a deliberate backdoor. Listen to the article or read the transcript, then think about it a little. Now, he's not saying *what* Microsoft put this in for. Did someone put this in for testing -that's my take, from a programmer perspedctive but .. who the heck knows. That's sorta the problem with proprietary software, we might never know. Buyer beware.

Steve: Well, I mean, as you've mentioned a couple times here, I mean, one of the advantages of an open source system is, you know, and I'm finding myself gravitating more and more toward open source solutions because of their transparency. And so, you know, but an advantage of that is that all kinds of people are looking at the code, and there's just no opportunity, especially when you build the system yourself from source, there's no opportunity for anything evil to get stuck in. And also, about this what appears to be a Windows MetaFile backdoor that's always been in Windows from 2000 on, you know, they've done recently serious security reviews of all their code. You know, they took that whole timeout from all the work they were going to be doing and said they were rereading all their code. And this is not the first time metafiles have had a problem. There have been what are probably real bugs in metafile processing in the past, I think two of them. So the whole metafile system would have come under the scrutiny of someone, you know, very deliberately. Now, you know, if Microsoft had said last week, whoops, this was an undocumented backdoor or means for us to run code in a metafile, we never documented it, our security sweeps didn't find it, blah blah blah - but nothing was said. They allowed the industry to believe that this was just like all their other code mistakes, but this wasn't like all their other code mistakes.

MSRC responds: Intentional Back door? um no.

[Stepto]

We've blogged about this already providing the background of the bug:

http://blogs.technet.com/msrc/archive/2006/01/13/4 17431.aspx

I emailed Zonk about it but I don't think he's had a chance to update the posting.

Long story short the idea that this is intentional rests on the premise that only an incorrect value produces the vuln. That is totally wrong, both correct and incorrect values trip the vulnerability. Besides doesn't it seem odd to create a backdoor that would require the user to first visit a website? What, were we going to take out a superbowl ad suggesting people visit www.microsoft.com so we could...uh...what exactly?

S.