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Swiss Researchers Exploit Windows Password Flaw
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)."
LanMan is not used on win2000 and winXP machines.
NThash dont know, probably not.
This hack is obsolte
"We fear, however, that the titles of these articles are a little sensational. While it is true that the LANMAN and NTHash windows password techniques have issues, the paper that kicked off this whole hub-bub [PDF] describes a refinement of an existing attack, not a new attack. We wanted to remind our readers that adequate password security is a good idea, whether your windows systems are being attacked with an adversary with an old copy of L0phtCrack, or with Philippe Oechslin's new system."
Read it all here
This only works with NTML v1. Not with NTML v2.
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.
You'll notice the line:
/208,827,064,576 /6,634,204,312,890,620
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...
BSD is designed. Linux is grown. C++ libs
You've made a supposition that MS passwords are marginally weaker than Unix passwords. Read the article, and there's a more basic factor at work.
/etc/shadow.
>"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.
The living have better things to do than to continue hating the dead.
The game's over with admin rights to every workstation. With this scenerio, once you're admin on one computer of the network, it's quick to get every other password on the network, such as domain admins. On Unix, Linux, and Mac OS X, if you're admin and have the hash entries you can't use them to crack into other computers on the same network because of the random bits added to each hash.
Developers: We can use your help.
This authN method is 8 or 9 years old. You can disable the NT hash by using either a password length of more than 14 chars or by using a simple registry value on Windows 2000 SP2 systems or higher. This KB explains how. Any good sys admin should have the LM hash disabled on all Windows machines by default anyways and set strong passwords which contains more than simple letters and numbers.
Mindless Microsoft bashing at it's best!
You can (and should) disable NTLM authentication if you're running Windows 2000 or 2003. This is very easy to do and makes any server immune to this type of hashing attack. It's even listed in Microsoft's Best Practices documentation for administrating their servers. It might cause problems with older Win9x clients, but there are updates to these clients that allow them to get along without NTLM.
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.
In the end they will lay their freedom at our feet and say to us, Make us your slaves, but feed us. - Fyodor Dostoyevsky
The article makes a statement that I think is untrue:
Using a tool like Cain & Able, 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.
Join Tor today!
Go here and use their nt password recovery tool. Click here for the floppy boot disk or click here for the cd boot image (only 2.0 mb)
This works well on Win2k machines and WinXp boxes with sp 3 and 1 respectively as well as the native installs.
cheers!
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).
Poul-Henning Kamp -- FreeBSD since before it was called that...
"Originally, we were targeting NT to the Intel i860 (code-named 'N-Ten)', a RISC processor that was horribly behind schedule. Because we didn't have any i860 machines in-house to test on, we used an i860 simulator. That's why we called it NT, because it worked on the 'N-Ten.'"
-Mark Lucovsky
Distinguished Engineer
Windows Server Architect
"If he thinks he can hide and run from the United States and our allies, he's sorely mistaken." Bush on bin Laden