Swiss Researchers Exploit Windows Password Flaw 519
Bueller_007 writes "CNET is carrying an article about a new (albeit simplistic) method used to hack alphanumeric Windows passwords in a matter of seconds, rather than minutes. To blame is a 'weakness in Microsoft's method of encoding passwords.' According to the authors, the same method, when used on Mac OS X, Unix and Linux boxes, however, could require either 4,096 times more memory or 4,096 times longer."
A few more details: Mister.de writes "As an example we have implemented an attack on MS-Windows password hashes. Using 1.4GB of data (two CD-ROMs) we can crack 99.9% of all alphanumerical passwords hashes (2 37 ) in 13.6 seconds whereas it takes 101 seconds with the current approach using distinguished points. We show that the gain could be even much higher depending on the parameters used. This was found at the
Cryptography and Security Laboratory of the Swiss Federal Institute of Technology in Lausanne (EPFL)."
This is why... (Score:5, Funny)
Re:This is why... (Score:3, Interesting)
I have seen BIOSes that did not encrypt the password at all.
Re:This is why... (Score:3, Interesting)
True, but that is not really the problem. There are two different issues.
Obviously an intruder that can get the password can also get access to the system, but it doesn't have to be the other way around. Why is that even interesting? Well, if the same password is used in a different place, it will be interesting to protect the password even if the
Re:This is why... (Score:5, Funny)
Re:This is why... (Score:3, Funny)
Come on, everybody knows that one.
Re:This is why... (Score:3, Funny)
Re:This is why... (Score:4, Informative)
Re:This is why... (Score:5, Insightful)
Building a lock that cannot be picked by a blind man is a lot easier (and less effective in the real world) than building a lock that cannot be picked by someone with the blueprints.
Re:This is why... (Score:3, Insightful)
Security through obscurity works just fine as long as that's not your only defense. Security practices should always be done in-depth, with multiple tools to protect you. Let's say I have my gold in a safe in my house. Rather than just put my safe in the garage (where it's not obscured at a
Re:This is why... (Score:5, Insightful)
This is just plain false. If it were true, then there would be MUCH more attacks against Apache than IIS - but the reverse is true.
Also, even if this assertion were true, can you provide references for it (as I asked in my previous post)? Let's see some posts from Linux users who think that they're immune from hack attempts because they run Linux and not windows.
And before you start yammering about Many eyes/shallow bugs or whatever, I shall use my new favorite example: the sobig worm.
First, a worm is not a hack attempt - it's malware (along with viruses.)
Second, malware such as this has little to do with obscurity - it has to do with a mindset that ignores basic security practices (namely segregation of resources.)
Re:This is why... (Score:3, Informative)
Re:This is why... (Score:4, Insightful)
Re:This is why... (Score:3, Interesting)
My thoughts? Apache doesn't pro
Re:This is why... (Score:3, Funny)
Re:This is why... (Score:3, Informative)
This is still a big deal. NT4 with LanMan auth is big, so is W2K in compatibility mode for 16-bit clients.
MS always ships the old stuff - usually running by default - along with the new.
The NT 4 customers who won't or can't move their apps are a problem. MS licenses are long ago paid. The shops are mostly self-supporting. It's revenue that MS can't get to. This is why they bought VirtualPC. They want to migra
Performance increase (Score:5, Insightful)
People are really running out of interesting stuff to "research", aren't they...
Re:Performance increase (Score:3, Funny)
Re:Performance increase (Score:3, Informative)
Solution:
YMMV, depending on whether you have execs of the sweaty oily finger variety, or the scaly lizard species.
Re:Performance increase (Score:5, Funny)
> 1.Wipe the pad clean.
> 2.Wait a few hours.
> 3.Blow chalk on it and brush gently.
> 4.Note which 3 digits have chalk stuck to them.
> 5.Try the six possible combinations.
> 6.Bingo! You're an executive.
Tried it. No chalk remaining on any of the four pads.
> YMMV, depending on whether you have execs of the sweaty oily finger variety, or the scaly lizard species.
Incidentally, what's the polite way of telling your boss he's got chalk on his nose, especially on a day when he seems to be real pissed off about something, but he won't say what's buggin' him? He's got a press conference in 20 minutes, and I don't know how to bring this up.
"Mr. Valenti, you have chalk on your nose" seems too direct, don't you think?
Re:You forgot... (Score:3, Funny)
Step 1.5.1 Stuff dounuts with laxatives before distributing them.
Of course afterwards you're probably going to want to use a different bathroom afterwards...
Re:Performance increase (Score:3, Funny)
Re:Performance increase (Score:5, Insightful)
Let's say it usually took 200 days to crack a password. A company could enforce a 90-day (3 month) requirement to change passwords, and a brute force technique would have roughly a 1-in-2 chance of getting a password in any given 90-day period. Now they increased it by a factor of 10.
Now it takes 20 days to crack a password. If the company want to keep the same level of password security, users would have to change their passwords every 7 days!
This is a pretty big issue.
Re:Performance increase (Score:5, Insightful)
I can't imagine it would have made the front page at all if not for the usual "See how insecure Micro$oft is!" Slashdot biases.
Re:Performance increase (Score:5, Funny)
Re:Performance increase (Score:3, Funny)
The users'll complain, but we'll be secure from this exploit!
Re:Performance increase (Score:5, Funny)
Re:Performance increase (Score:3, Interesting)
Company Memo: New security procedures. (Score:5, Funny)
As you know we have a company security policy based around frequently changing passwords, in order to keep our Windows network secure.
Previously, as you are all no doubt aware, you were required to change your Windows passwords once every 90 seconds, since NT passwords can be cracked in 100 seconds flat.
Due to recent developments in MS password cracking, we will now be requiring all employees to change their passwords once every 10 seconds, to ensure they remain secure.
We hope this will not detract from productivity, and apologise for any inconvenience it does cause.
thanks,
Management
Re:Company Memo: New security procedures. (Score:3, Funny)
Re:Performance increase (Score:3, Insightful)
Re:Relevancy scenario (Score:4, Informative)
I'll buy that certainly for situations where you want to 0wnz0r every account, but usually you only need one priveleged one. From there, everything's candy.
Besides, before that you could only crack into your evil co-worker station when he was away for a cup of coffe. Now it is enough for him to be distracted by the hot boss assistant's legs...
The who....mmmmm...leggggs....ah shit, somebody h4X0r3d my box! ;) Seriously, as I understand it though, all you do at the local machine is get the hashes - which takes a fixed amount of time. The processing time is all on your own machine. And as I said, unless I want every account on the machine, I'll surf the net for the extra 90 seconds or whatever while that shit's a-crackin'.
I mean, I appreciate them saving me the extra 90 seconds and all,thanx guys, but I'm much more afraid that it takes anywhere as short as 2 minutes in the first place, ya know? I'd feel better with, say, months. To me, the most relevant thing about this is the nice web page the put up where they'll crack windows hashes for you. Very considerate, guys. ;)
Scary stuff... (Score:3, Interesting)
Linux / Mac OSX passwords hacked within an hour too probably...
Maybe we need something just a little stronger!
Re:Scary stuff... (Score:5, Funny)
When that happens I'll feel safe
Re:Scary stuff... (Score:5, Funny)
Before you can logon you must answer three questions...
Re:Scary stuff... (Score:4, Funny)
Or bridge..
A Troll Bridge?
Ha!
No salt (Score:5, Informative)
>"Windows passwords are not very good," he wrote. "The problem with Windows passwords is that they do not include any random information."
From what I understand, Unix passwords normally take a little 'salt', a little random information, as well as the user password, and hash that. Microsoft just hashed the user password without the salt. This makes it easier to crack., anything else aside.
To their credit, you have to be Admin to get to the password hashes, rather like
To their debit, most WinDesktops that I'm aware of end up as glorified single-user machines, and that user is also.... Admin. Finally build a decent security model, and then customers ignore it.
Re:No salt (Score:5, Insightful)
I think the customers only ignore it because they've been bred on Win9x, which sort of casually asked if you felt like typing in a password, but didn't really care one way or the other if you actually did. You can't train people that passwords don't matter for 7 years and then expect them to start caring about security when you finally decide to implement it. So now we have a sea of internet users who don't know or care one whit about security all because they've been taught from the very beginning that all they ever have to do is plug it in, turn it on, and start browsing.
Re:No salt (Score:3, Informative)
Traditionally the salt is a 2 byte random value. It is stored as the first 2 bytes of the hashed password, but has nothing to do with the password or username at all.
Before shadow passwords were standard this was no real help at all, since all you had to do was read
Re:No salt (Score:5, Informative)
The String -> MD5 hash is an easy converison, it was designed to work nicely on 32 bit processors
The MD5 -> String reverse-hash is not an easy conversion. So even if you give out the md5sum of your password, getting the actual password from that hash value is not trivial.
That is why it is more secure. Now MD5 is not invulnerable. I have read some reports about more mathematical vulnerabilities in it. Some say that SHA-1 crypto hashing is the only way to do things now adays.
Re:No salt (Score:3, Insightful)
Switching to MD5 without salt would not stop this attack, since you don't have to do MD5 -> String convertion, just lots of String -> MD5 hash conversions, and these are very fast.
"setting up XP" (Score:3, Informative)
Well, (Score:4, Funny)
Please Advise, I don't know how to think about this story, I'm a Swiss-American.
Ted
Yoddle-Aay-Hee-Hooo (Score:5, Funny)
Re:Yoddle-Aay-Hee-Hooo (Score:3, Funny)
To Redmond we go! Every one click:
http://www.microsoft.com/
C'mon geeks, nerds, and dweebs UNITE. We can Slashdot the Borg and overtake the monopolistic opression we are so tired of battling.
One problem (Score:5, Informative)
NThash dont know, probably not.
This hack is obsolte
Re:One problem (Score:3, Informative)
Just because it's called NThas doesn't mean it died with NT. LanMan was used until early releases of NT. The Win2000 bootup screen says "Built with NT technology". Whatever that means it implies lots of shared code. Since NThas was introduced with NT its unlikely they just drop it, especially since it was an improvement and they didn't care to fix this one major weakness a
Nope (Score:5, Informative)
-Mark Lucovsky
Distinguished Engineer
Windows Server Architect
Re:One problem (Score:3, Informative)
You must be a recent arrival :). Back when NT was new, "everyone" knew it stood for "New Technology".
It's been a while since I've seen an NT4 machine boot, but I think it and earlier versions actually had "New Technology" on their boot screens.
BTW, can anyone tell me what the hell XP is supposed to stand for?
I think it's supposed t
Re:One problem (Score:5, Informative)
The LANMAN hashes are still used in Win2k. They are enabled and kept in the ActiveDirectory by default.
If your a 100% Win2k or higher shop, you can disable the LANMAN hashes and use NTLM 2 hashes exclusively.
Microsoft is willing to tell you how, if you look here [microsoft.com], along with some details about the whole subject.
Hello, my name is Shakey Weaselteat and this is a song about a whale ...
Re:One problem (Score:5, Informative)
NTLMv2 was introduced in Windows 2000 and is still not the default; Windows Server 2003 Enterprise defaults to 'Send NTLM only', which will stop LanMan attacks, but not prevent NTLM attacks. It will also not ALLOW NTLMv2 to be used, even if the client supports it. I.E. the only secure authentication system which is available is disabled by default.
Yes, all the MS security practise documents will tell you to set it to NTLMv2 only (which requires upgrading all clients to Windows 2000 or above).. but it's still not the *default*. Enabling NTLMv2 does not break backward compatibility (only disabling v1 does), so I'm not sure how they justify this decision =)
Torne
Of course the Swiss were able to hack it... (Score:5, Funny)
I don't understand (Score:5, Insightful)
Re:I don't understand (Score:5, Insightful)
Re:I don't understand (Score:5, Informative)
About hashes and salted passwords (Score:3, Informative)
Anyone who want to learn more about how UNIX Password security was designed should read this paper [ja.net] by Robert Morris and Ken Thompson that explains things like hashes (one way cryptographic functions) and salted passwords.
Re:I don't understand (Score:4, Interesting)
- Somebody reads an email with a simplified hack based on this embedded within it (don't need the whole dataset, you just reduce your hit rate)
- They unwittingly send back the machine info and an admim-level password to the hacker. (where I work, all 'owners' have admin rights on their system).
- From this, they can get admil-level access permanently, as well as a chance to download the full crack via a backdoor and get the network admin password, and from there, the whole network.
Administor rights not _technically_ needed ... (Score:3, Interesting)
Re:I don't understand (Score:3, Insightful)
Sorry to interrupt your tirade here ... there's no need to get the tables onto the target machine and run the cracker remotely, you just have to sneak the password hash back onto your loca
Is this really news worthy? (Score:4, Insightful)
Bruce Schneier talks about all of these attacks and weaknesses in his book "Applied Cryptography" which was published years ago.
Actually... (Score:3, Informative)
In this case, the "dictionary" consists of, not just a list of words, but a list of strings and their encrypted companions.
But you're still right: not really news worthy.
Nothing new (Score:5, Informative)
Read it all here [cryptonomicon.net]
I hope someone hacks my passwords at work (Score:5, Funny)
Oh, and the backups too. Just point your password crackers to
Re:I hope someone hacks my passwords at work (Score:5, Funny)
Only works with NTMLv1, NTLM v2 not effected. (Score:5, Informative)
In order to prevent this
Using secpol.mmc,
in you security pocilies set the LAN manager authentication level to 'NTLMv2 response only refuse LM & NTLM'
The passwords are only crackable if you have Win 9x machines in your doamin.
If you have Windows 2000/2003 domain without Win 9x machines then you passwords cannot be recovered.
Admins can prevent Windows 9x machines from logging in to the network.
This is reason enough to migrate to Windows XP.
Security as an Upgrade Path (Score:3, Insightful)
I'ill give NT4 as an example which is EOL'd. You're a company who has managed to get your NT4 server rock solid. A new security flaw comes out and since NT4 is EOL'd MS says no security patch for you, upgrade to Win2K.
Of course if you was a complete conspiracy theorist you could say even MS would leak holes in their old prod
If You RTA (Score:5, Informative)
Users can protect themselves against the attack by adding nonalphanumeric characters to a password. The inclusion of symbols other than alphanumeric characters adds complexity to the process of breaking passwords--and that means the code cracker needs more time or more memory or both.
For those that don't realize considering the following for example:
# characters/Upper Case Only
8
# characters/Upper, Lower, Numbers & Symbols
8
This post is more for the types that really don't consider their password selection...
This week only (Score:4, Funny)
New New NEW. Lower Prices! Krazy Bill is just GIVING these away. Come on down. He's Krazy Krazy KRAZY to license this software with these terms! Get yours TODAY!
What The...? (Score:4, Funny)
They *exploit* a Windows password flaw? (Score:4, Funny)
I guess you could argue they [i]exploited[/i] it in order to publish their research results, as much as a planetary scientist exploits images of Mars to publish a new theory on subsurface water.
So? (Score:5, Insightful)
With distributed computing, why bother? (Score:5, Insightful)
Even if the 12 bit salt for mac/linux/etc was increased in size, a scale up in the number of computers used would defeat this added protection. The trend in the comp world seems to be more connectivity between large numbers of computers. All it takes is one disgruntled folding@Home grad student out at stanford to break even the most stringent password.
It seems that increasing the size of the salt would prevent the average script kiddie from breaking your password, but does nothing to alleviate the threat distributed computing presents. So what other options are there?
Re:With distributed computing, why bother? (Score:5, Informative)
FreeBSD started using 64 bit salt and MD5 scrambled passwords back in 1994 (when I wrote the code) and since then NetBSD, OpenBSD, Cisco, GLIBC and presumably MAC OSX have adopted that code.
Look for the tell-tale "$1$..." magic marker.
(The fact that GLIBC doesn't correctly attribute the algorithm is somewhat sad, but they refused to do so, even when asked directly).
Re:With distributed computing, why bother? (Score:4, Funny)
I've always taken Microsoft security... (Score:4, Funny)
rimshot
I for one welcome our new Swiss Overlords!!! (Score:5, Funny)
Wow, less memory? (Score:5, Funny)
Nanite
Welcome to the 90s (Score:5, Informative)
Mindless Microsoft bashing at it's best!
Hack obsolete on curent Windows servers (Score:5, Informative)
If you're running Active Directory in Native Mode, NTLM is easily kicked to the curb. However, NT4 machines remain vulnerable to this hack. Yet another reason to just get off of NT.
Incorrect Information In The Article (Score:5, Informative)
The article makes a statement that I think is untrue:
Using a tool like Cain & Able [www.oxid.it], it is possible to get access to this information without having administrative rights.
You can also dump the hashes using Cain & Able's password cracking tool. It is really quite trivial to do.
By the way, you can easily acquire the passwords of the last five users who logged into an NT system. They are stored in LSA "secrets", an area of memory which is easy to dump. Cain & Able does this for you.
Have fun.
Re:Incorrect Information In The Article (Score:3, Interesting)
To sniff traffic it requires installing a packet driver... which also requires administrative rights.
The point of the article is not just Windows... (Score:3, Interesting)
The point of the article is to show off a faster, new time-memory trade-off technique, not to just down-play Windows security. The manner in which Window's password security is built simply provided an error-free sandbox for this method to be tested, and exemplified.
Don't feed the trolls.
Only 4096 more time on Unix ? (Score:5, Insightful)
Passwords hashed with MD5 and Blowfish don't have the 8 character limitation. There are still some people who like to assign users passwords like "*9_p7Z9ox" even though their system doesn't use single DES any more. This is just plenty stupid. Not only it's a hell to remember for the end user, but it's damn fast to brute force when hashes are precomputed as described in this article.
A normal password like a real sentence (ex: "I'd like to have sex with Sandra") is not only way more easy to remember, it's also orders of magnitudes harder to brute force.
Re:Only 4096 more time on Unix ? (Score:5, Interesting)
If this is the case, it implies that Windows password hashes do not use salts. Now, I'm not claiming that salting makes the process secure (it doesn't), but it does make it orders of magnitude more intensive to compute a complete hash dictionary. At the expense of 12 bits per password (hell, use more if you want!) it seems worth it to use salts.
UNIX uses 64 bits salt (Score:5, Interesting)
There is no immediate future for a table driven attack on this algorithm (Which can be recognized by the '$1$...' prefix.
HP-UX, Solaris and AIX, however still use the old 12 bit salted DES derived passwords.
Why this doesn't matter AT ALL (Score:3, Insightful)
This isn't a security problem.
Windows password hashes (both the LanManager hash described here and the newer NT hash) are never sent "in the clear" over a network, or accessible to non-admins.
Why? Because they are plaintext-equivalent. Most NT network protocols treat the hash itself as a shared secret and do not make any attempt to verify that you know the actual password.
Yes, that's right. You already don't need to know the user's unencrypted password - except possibly for changing it (I can't remember offhand whether the various password-change calls require proof of knowledge of the old password - but I don't think they do either). Once an attacker gets the hashes out of your SAM, the game is already up, even if he can't decrypt them.
Given this fact, I sometimes wonder why Microsoft even bothered to try making NTLM a secure hash. BASE64 would have done pretty much the same job.
Move along, nothing to see here. Your passwords are just as secure, or as insecure, as they ever were.
Not really that much of an issue... (Score:3, Interesting)
To be honest, this isnt as much of a scare as most people would think. A person willing to crack a password in ~13.6 seconds would no doubt be willing to take the extra minute regardless.
Plus you need Administrator privelages to get the hash file anyways, so you'd be able to access anything needed locally anyways.
Finally, crackers wouldnt be able to escalate to these privelages in the first place (hey, they wouldnt have any access on the system), so there really isnt anything for anyone to be concerned.
Symbols in the password (Score:3, Informative)
After a dozen or so times typing it in, you actually start to remember it. For those wondering, that password is something I just made up. I don't actually use it. =P~
-Lucas
Either Or (Score:3, Funny)
What is not made clear... (Score:3, Informative)
If you don't choose a decent password, then, well, your password will take five minutes to crack rather than 13.6 seconds. Feel better?
Re:What is not made clear... (Score:3, Informative)
Oh no! What about my PWLs! (Score:3, Funny)
Mindless Self Promotion (Score:3, Interesting)
Re:Time for OSX, UNIX, Linux (Score:4, Insightful)
Now to keep it close to 13 secs, you would need 4096x more data - 1.4G x 4096 = ~5.7 Terabytes.
If you don't have any data, and have 4096 more combinations, you need to take 4096 x 1m41s ~= 4.8 days. Not quite as bad but it still looks like like we need a few more bits for the password salt...
We should just make it a 64-bit salt and not have to worry about it until Quantum computers are viable..
Re:Lost Win XP Pro password (Score:3, Informative)
Re:Lost Win XP Pro password (Score:3, Informative)
Michael
Re:Lost Win XP Pro password (Score:5, Informative)
This works well on Win2k machines and WinXp boxes with sp 3 and 1 respectively as well as the native installs.
cheers!
Re:Gee... (Score:5, Insightful)
Why bother cracking NT (and Win2K/XP) passwords when you can just overwrite [eunet.no] them? Boot from this floppy and you can change any local password (including the administrator). It's been useful on more than one occasion at work...when somebody quits or is fired, I can go in and retrieve everything in just a few minutes.
That they're nearly as trivial to crack is somewhat disturbing...but given the ready availability of the password changer, it doesn't make Windows significantly less secure than it already is (hell, it can't get much less secure).
physical access (Score:5, Interesting)
Because this doesn't require physical access to the machine? Because now some l33t d00d from another country can get passwords?
Re:How does the salt work? (Score:3, Informative)
Re:WTF is it with you security guys! (Score:4, Insightful)