The Offline NT Password Editor(c) 1997-2004 Petter Nordahl-HagenSee COPYING for copyright & credits.See INSTALL for compile/installation instructions.Where to get more info:-----------------------http://home.eunet.no/~pnordahl/ntpasswd/At that site there's a floppy and a bootable CD that use chntpw toaccess the NT/2k/XP-system it is booted on to edit password etc.The instructions below are for the standalone program itself, not the floppy.What does it do?----------------This little program will enable you to view some information andchange user passwords in a Windows NT SAM userdatabase file.You do not need to know the old passwords.However, you need to get at the file some way or another yourself.In addition it contains a simple registry editor with full write support,and hex-editor which enables you tofiddle around with bits&bytes in the file as you wish yourself.Why?----I often forget passwords. Especially on test installations (thatI just _must_ have some stuff out of half a year later..)On most unix-based boxes you just boot the thingy off some kindof rescue bootmedia (cd/floppy etc), and simply edit thepassword file.On Windows NT however, as far as I know, there is no way except reinstallingthe userdatabase, losing all users except admin.(ok, some companies let you pay lotsa $$$$$ for some rescue service..)How?----Currently, this thing only runs under linux, but it may just happento compile on other platforms, too.(there are dos-versions available, look for links on my webpage)So, to set a new adminpassword on your NT installation you either:1) Take the harddrive and mount it on a linux-box2) Use a linux-bootdisk or CD   one is available at: http://home.eunet.no/~pnordahl/ntpasswd/ie. you do it offline, with the NT system down.Usage:------	chntpw version 0.99.2 040105, (c) Petter N Hagen	chntpw: change password of a user in a NT SAM file, or invoke registry editor.	chntpw [OPTIONS] <samfile> [systemfile] [securityfile] [otherreghive] [...]	 -h          This message	  -u <user>   Username to change, Administrator is default	  -l          list all users in SAM file	  -i          Interactive. List users (as -l) then ask for username to change	  -e          Registry editor. Now with full write support!	  -d          Enter buffer debugger instead (hex editor), 	  -t          Trace. Show hexdump of structs/segments. (deprecated debug function)	  -v          Be a little more verbose (for debuging)	  -L          Write names of changed files to /tmp/changed	  -N          No allocation mode. Only (old style) same length overwrites possibleNormal usage is:> chntpw sam system security  - open registry hives 'sam' and 'system' and change administrator account.  Verions dated later from Feb 1999 and later also supports  and will find the admin account, even if the name has been changed,  or the name has been localized (different languageversion of NT  use different admin-names)The -u option:Specifies user to change:> chntpw -u jabbathehutt mysam  - Prompt for password for 'jabbathehutt', if found (otherwise do nothing)  Or you may give RID number in hex:> chntpw -u 0x1f4 mysam  - Will edit administrator.Names does not support multibyte (unicode) characters likesome russian and asian locales. Give RID in hex to edit userswith such names. Must start with 0x. Ex: 0x2faThe -l option:  Will list all users in the sam-file.  The -i option:  Go into the interactive menu system.  The -d option:  This will load the file, and then immediately enter the  buffer debugger.  This is a simple hex-editor with only a few commands,  enter ? at the . prompt to se a short command overview.  'q' exits without saving, 's' exit and saves.The -e option:  Will enter the registry editor.  You can navigate the registry like a filesystem at the command-line prompt:  See regedit.txt file for more info.The -t option:  This is a debug function (extended -l) to show how it traces the chain  of structs in the file. This also includes a raw interpretation  of the different registry structures + a hex dump.The -L option:  Drops the filenames of the changed hives in /tmp/changed  Used by the floppy scripts.  The -N option:  Will fall back to old edit mode, disable the block allocations  and only support overwrite-same-size. Used to ensure safety  in testing period.How does it work:-----------------A struct, called the V value of a key in the NT registrywas suddenly somewhat documented through the pwdump utilityincluded in the unix Samba distribution.This struct contains some info on a user of the NT machine,along with 2 crypted versions of the password associatedwith the account.One password is the NT console login password,the other the LANMAN network share password(which essentially is the first one in uppercase only, and no unicode)This is how NT encrypts the passwords:The logon cleartext password a user enters is:1) Converted to unicode2) A MD4 hash is made out of the unicode string3) Then the hash is crypted with DES, using the RID (lower   part of the SID, userid) as the crypt key.   This is the so called "obfuscation" step, so   it's not obvious on a hex dump of the file   that two or more users have the same password.4) The result of stage 3 (16 bytes) is put into the V struct.For the LANMAN password:1) Uppercased (and illegal characters probably removed)   14 bytes max, if less the remaining bytes are zeroed.2) A known (constant) string is DES-encrypted   using 7 first characters of the password as the key.   Another constant is encrypted using the last 7 chars   as the key.   The result of these two crypts are simply appended,   resulting in a 16 byte string.3) The same obfuscation DES stage as 3 above.4) 16 bytes result put into the V struct.Since the number of possible combinations in the lanmanpassword is relatively low compared to the other one,and it's easy to see if it's shorter than 8 chars or notit's used first in brute-force-crackers.This program, however, don't care at all what the oldone is, it just overwrites it with the new one.Ok. So, how do we find and identify the V struct?Yeah.. that was the hard part.. The files structureis not documented (as far as I know..)But, with help from an unnamed German, and a lot of testingand guesswork from myself, it's now possible to followthe actual registry tree. (see source code for struct-definesand comments on the registry structure)The usernames are listed in:\SAM\Domains\Account\Users\Names\[2d18] \SAM\Domains\Account\Users\Names> lls of node at offset 0x2d1cNode has 4 subkeys and 1 valuesnk-offset      name0x003290 - <Administrator>0x003630 - <Guest>0x001c88 - <luser>0x003428 - <pnh>Each name is a subkey, with one namless value containingthe RID.[2d18] \SAM\Domains\Account\Users\Names> cd pnh[3428] \SAM\Domains\Account\Users\Names\pnh> lls of node at offset 0x342cNode has 0 subkeys and 1 valuesvk-offs    size    type           name0x003688     0  (unknown)        <> INLINE:  val (in type field?): 1000 (0x3e8)To get the userinfo (V struct), access\SAM\Domains\Account\Users\<RID>\V[2c90] \SAM\Domains\Account\Users> lls of node at offset 0x2c94Node has 5 subkeys and 1 valuesnk-offset      name0x003320 - <000001F4>0x0036b8 - <000001F5>0x003550 - <000003E8>0x001d00 - <000003E9>0x002d18 - <Names>[2c90] \SAM\Domains\Account\Users> cd 000003E8[3550] \SAM\Domains\Account\Users\000003E8> lls of node at offset 0x3554Node has 0 subkeys and 2 valuesvk-offs    size    type           name0x0035a8    80  REG_BINARY       <F>0x003228   508  REG_BINARY       <V>For more techincal info, look it up in the source code.