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SMBPASSWD(5)
NAME
smbpasswd - The Samba encrypted password file
SYNOPSIS
smbpasswd
DESCRIPTION
This tool is part of the Sambasuite.
smbpasswd is the Samba encrypted password file. It contains the username,
Unix user id and the SMB hashed passwords of the user, as well as account
flag information and the time the password was last changed. This file
format has been evolving with Samba and has had several different formats
in the past.
FILE FORMAT
The format of the smbpasswd file used by Samba 2.2 is very similar to the
familiar Unix passwd(5) file. It is an ASCII file containing one line for
each user. Each field within each line is separated from the next by a
colon. Any entry beginning with '#' is ignored. The smbpasswd file contains
the following information for each user:
name This is the user name. It must be a name that already exists in the
standard UNIX passwd file.
uid This is the UNIX uid. It must match the uid field for the same user
entry in the standard UNIX passwd file. If this does not match then
Samba will refuse to recognize this smbpasswd file entry as being
valid for a user.
Lanman Password Hash
This is the LANMAN hash of the user's password, encoded as 32 hex
digits. The LANMAN hash is created by DES encrypting a well known
string with the user's password as the DES key. This is the same
password used by Windows 95/98 machines. Note that this password hash
is regarded as weak as it is vulnerable to dictionary attacks and if
two users choose the same password this entry will be identical (i.e.
the password is not "salted" as the UNIX password is). If the user has
a null password this field will contain the characters "NO PASSWORD"
as the start of the hex string. If the hex string is equal to 32 'X'
characters then the user's account is marked as disabled and the user
will not be able to log onto the Samba server.
WARNING !! Note that, due to the challenge-response nature of the
SMB/CIFS authentication protocol, anyone with a knowledge of this
password hash will be able to impersonate the user on the network. For
this reason these hashes are known as plain text equivalents and must
NOT be made available to anyone but the root user. To protect these
passwords the smbpasswd file is placed in a directory with read and
traverse access only to the root user and the smbpasswd file itself
must be set to be read/write only by root, with no other access.
NT Password Hash
This is the Windows NT hash of the user's password, encoded as 32 hex
digits. The Windows NT hash is created by taking the user's password
as represented in 16-bit, little-endian UNICODE and then applying the
MD4 (internet rfc1321) hashing algorithm to it.
This password hash is considered more secure than the LANMAN Password
Hash as it preserves the case of the password and uses a much higher
quality hashing algorithm. However, it is still the case that if two
users choose the same password this entry will be identical (i.e. the
password is not "salted" as the UNIX password is).
WARNING !!. Note that, due to the challenge-response nature of the
SMB/CIFS authentication protocol, anyone with a knowledge of this
password hash will be able to impersonate the user on the network. For
this reason these hashes are known as plain text equivalents and must
NOT be made available to anyone but the root user. To protect these
passwords the smbpasswd file is placed in a directory with read and
traverse access only to the root user and the smbpasswd file itself
must be set to be read/write only by root, with no other access.
Account Flags
This section contains flags that describe the attributes of the users
account. In the Samba 2.2 release this field is bracketed by '[' and
']' characters and is always 13 characters in length (including the
'[' and ']' characters). The contents of this field may be any of the
characters.
o+ U - This means this is a "User" account, i.e. an ordinary user. Only
User and Workstation Trust accounts are currently supported in the
smbpasswd file.
o+ N - This means the account has no password (the passwords in the
fields LANMAN Password Hash and NT Password Hash are ignored). Note
that this will only allow users to log on with no password if the
null passwords parameter is set in the smb.conf(5) config file.
o+ D - This means the account is disabled and no SMB/CIFS logins will
be allowed for this user.
o+ W - This means this account is a "Workstation Trust" account. This
kind of account is used in the Samba PDC code stream to allow
Windows NT Workstations and Servers to join a Domain hosted by a
Samba PDC.
Other flags may be added as the code is extended in future. The rest of
this field space is filled in with spaces.
Last Change Time
This field consists of the time the account was last modified. It
consists of the characters 'LCT-' (standing for "Last Change Time")
followed by a numeric encoding of the UNIX time in seconds since the
epoch (1970) that the last change was made.
All other colon separated fields are ignored at this time.
VERSION
This man page is correct for version 2.2 of the Samba suite.
SEE ALSO
smbpasswd(8), samba(7), and the Internet RFC1321 for details on the MD4
algorithm.
AUTHOR
The original Samba software and related utilities were created by Andrew
Tridgell. Samba is now developed by the Samba Team as an Open Source
project similar to the way the Linux kernel is developed.
The original Samba man pages were written by Karl Auer. The man page
sources were converted to YODL format (another excellent piece of Open
Source software, available at ftp://ftp.icce.rug.nl/pub/unix/
<URL:ftp://ftp.icce.rug.nl/pub/unix/>) and updated for the Samba 2.0
release by Jeremy Allison. The conversion to DocBook for Samba 2.2 was done
by Gerald Carter
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Index for
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Alphabetical
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