CHNTPW(8)CHNTPW(8)NAMEchntpw - utility to overwrite passwords of Windows systems
SYNOPSISchntpw [options] <samfile> [systemfile] [securityfile] [otherreghive]
[...]
DESCRIPTION
This manual page documents briefly the chntpw command. This manual
page was written for the Debian distribution because the original pro‐
gram does not have a manual page.
chntpw is a utility to view some information and reset user passwords
in a Windows NT/2000 SAM userdatabase file used by Microsoft Windows
Operating System (in NT3.x and later versions). This file is usually
located at \WINDOWS\system32\config\SAM on the Windows file system. It
is not necessary to know the previous passwords to reset them. In
addition it contains a simple registry editor and ahex-editor with
which the information contained in a registry file can be browsed and
modified.
This program should be able to handle both 32 and 64 bit Microsoft Win‐
dows and all versions from NT3.x up to Win8.1.
OPTIONS-h Show a summary of options.
-u username
Username or username ID (RID) to change. The default is 'Admin‐
istrator'.
-l List all users in the SAM database and exit.
-i Interactive Menu system: list all users (as per -l option) and
then ask for the user to change.
-e Registry editor with limited capabilities (but it does include
write support). For a slightly more powerful editor see reged
-d Use buffer debugger instead (hex editor)
-L Log all changed filenames to /tmp/changed. When this option
is set the program automatically saves the changes in the hive
files without prompting the user.
Be careful when using the -L option as a root user in a multi‐
user system. The filename is fixed and this can be used by
malicious users (dropping a symlink with the same name) to over‐
write system files.
-N Do not allocate more information, only allow the editing of
existing values with same size.
-E Do not expand the hive file (safe mode).
-v Print verbose information and debug messages.
EXAMPLES
ntfs-3g /dev/sda1 /media/win ; cd /media/win/WINDOWS/system32/config/
Mount the Windows file system and enters the directory \WIN‐
DOWS\system32\config where Windows stores the SAM database.
chntpw SAM system
Opens registry hives SAM and system and change administrator
account. This will work even if the name has been changed or it
has been localized (since different language versions of NT use
different administrator names).
chntpw-l SAM
Lists the users defined in the SAM registry file.
chntpw-u jabbathehutt SAM
Prompts for password for jabbathehutt and changes it in the SAM
registry file, if found (otherwise do nothing).
KNOWN BUGS
This program uses undocumented structures in the SAM database. Use with
caution (i.e. make sure you make a backup of the file before any
changes are done).
Password changing is only possible if the program has been specifically
compiled with some cryptographic functions. This feature, however, only
works properly in Windows NT and Windows 2000 systems. It might not
work properly in Windows XP, Vista, Win7, Win8 and later systems.
In the Debian distribution this feature is not enabled.
SEE ALSO
reged, samusrgrp, sampasswd
If you are looking for an automated procedure for password recovery,
you might want to check the bootdisks (can be used in CD and USB
drives) provided by the upstream author at http://pogo‐
stick.net/~pnh/ntpasswd/
You will find more information available on how this program works,
including in-depth details on how the registry works, in the text files
/usr/share/doc/chntpw/README.txt and /usr/share/doc/chntpw/MANUAL.txt
AUTHOR
This program was written by Petter N Hagen.
This manual page was written by Javier Fernandez-Sanguino
<jfs@debian.org>, for the Debian GNU/Linux system (but may be used by
others).
13th March 2010 CHNTPW(8)
