smbpasswd(5)

NAME

   smbpasswd - The Samba encrypted password file

SYNOPSIS

   smbpasswd

DESCRIPTION

   This tool is part of the samba(7) suite.

   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. 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 following
       characters:

       *   U - This means this is a "User" account, i.e. an ordinary user.

       *   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.

       *   D - This means the account is disabled and no SMB/CIFS logins
           will be allowed for this user.

       *   X - This means the password does not expire.

       *   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. For further information
   regarding the flags that are supported please refer to the man page for
   the pdbedit command.

   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 3 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/) and
   updated for the Samba 2.0 release by Jeremy Allison. The conversion to
   DocBook for Samba 2.2 was done by Gerald Carter. The conversion to
   DocBook XML 4.2 for Samba 3.0 was done by Alexander Bokovoy.

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