docs/htmldocs/smbpasswd.5.html

   1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>smbpasswd</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en"><a name="smbpasswd.5"></a><div class="titlepage"><div></div><div></div></div><div class="refnamediv"><h2>Name</h2><p>smbpasswd &#8212; The Samba encrypted password file</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><p><tt class="filename">smbpasswd</tt></p></div><div class="refsect1" lang="en"><h2>DESCRIPTION</h2><p>This tool is part of the <a href="Samba.7.html"><span class="citerefentry"><span class="refentrytitle">Samba</span>(7)</span></a> suite.</p><p>smbpasswd is the Samba encrypted password file. It contains
   2         the username, Unix user id and the SMB hashed passwords of the
   3         user, as well as account flag information and the time the
   4         password was last changed. This file format has been evolving with
   5         Samba and has had several different formats in the past. </p></div><div class="refsect1" lang="en"><h2>FILE FORMAT</h2><p>The format of the smbpasswd file used by Samba 2.2
   6         is very similar to the familiar Unix <tt class="filename">passwd(5)</tt>
   7         file. It is an ASCII file containing one line for each user. Each field
   8         ithin each line is separated from the next by a colon. Any entry
   9         beginning with '#' is ignored. The smbpasswd file contains the
  10         following information for each user: </p><div class="variablelist"><dl><dt><span class="term">name</span></dt><dd><p> This is the user name. It must be a name that
  11                 already exists in the standard UNIX passwd file. </p></dd><dt><span class="term">uid</span></dt><dd><p>This is the UNIX uid. It must match the uid
  12                 field for the same user entry in the standard UNIX passwd file.
  13                 If this does not match then Samba will refuse to recognize
  14                 this smbpasswd file entry as being valid for a user.
  15                 </p></dd><dt><span class="term">Lanman Password Hash</span></dt><dd><p>This is the LANMAN hash of the user's password,
  16                 encoded as 32 hex digits.  The LANMAN hash is created by DES
  17                 encrypting a well known string with the user's password as the
  18                 DES key. This is the same password used by Windows 95/98 machines.
  19                 Note that this password hash is regarded as weak as it is
  20                 vulnerable to dictionary attacks and if two users choose the
  21                 same password this entry will be identical (i.e. the password
  22                 is not "salted" as the UNIX password is). If the user has a
  23                 null password this field will contain the characters "NO PASSWORD"
  24                 as the start of the hex string. If the hex string is equal to
  25                 32 'X' characters then the user's account is marked as
  26                 <tt class="constant">disabled</tt> and the user will not be able to
  27                 log onto the Samba server. </p><p><span class="emphasis"><em>WARNING !!</em></span> Note that, due to
  28                 the challenge-response nature of the SMB/CIFS authentication
  29                 protocol, anyone with a knowledge of this password hash will
  30                 be able to impersonate the user on the network. For this
  31                 reason these hashes are known as <span class="emphasis"><em>plain text
  32                 equivalents</em></span> and must <span class="emphasis"><em>NOT</em></span> be made
  33                 available to anyone but the root user. To protect these passwords
  34                 the smbpasswd file is placed in a directory with read and
  35                 traverse access only to the root user and the smbpasswd file
  36                 itself must be set to be read/write only by root, with no
  37                 other access. </p></dd><dt><span class="term">NT Password Hash</span></dt><dd><p>This is the Windows NT hash of the user's
  38                 password, encoded as 32 hex digits.  The Windows NT hash is
  39                 created by taking the user's password as represented in
  40                 16-bit, little-endian UNICODE and then applying the MD4
  41                 (internet rfc1321) hashing algorithm to it. </p><p>This password hash is considered more secure than
  42                 the LANMAN Password Hash as it preserves the case of the
  43                 password and uses a much higher quality hashing algorithm.
  44                 However, it is still the case that if two users choose the same
  45                 password this entry will be identical (i.e. the password is
  46                 not "salted" as the UNIX password is). </p><p><span class="emphasis"><em>WARNING !!</em></span>. Note that, due to
  47                 the challenge-response nature of the SMB/CIFS authentication
  48                 protocol, anyone with a knowledge of this password hash will
  49                 be able to impersonate the user on the network. For this
  50                 reason these hashes are known as <span class="emphasis"><em>plain text
  51                 equivalents</em></span> and must <span class="emphasis"><em>NOT</em></span> be made
  52                 available to anyone but the root user. To protect these passwords
  53                 the smbpasswd file is placed in a directory with read and
  54                 traverse access only to the root user and the smbpasswd file
  55                 itself must be set to be read/write only by root, with no
  56                 other access. </p></dd><dt><span class="term">Account Flags</span></dt><dd><p>This section contains flags that describe
  57                 the attributes of the users account. In the Samba 2.2 release
  58                 this field is bracketed by '[' and ']' characters and is always
  59                 13 characters in length (including the '[' and ']' characters).
  60                 The contents of this field may be any of the following characters:
  61                 </p><div class="itemizedlist"><ul type="disc"><li><p><span class="emphasis"><em>U</em></span> - This means
  62                         this is a "User" account, i.e. an ordinary user. Only User
  63                         and Workstation Trust accounts are currently supported
  64                         in the smbpasswd file. </p></li><li><p><span class="emphasis"><em>N</em></span> - This means the
  65                         account has no password (the passwords in the fields LANMAN
  66                         Password Hash and NT Password Hash are ignored). Note that this
  67                         will only allow users to log on with no password if the <i class="parameter"><tt>
  68                         null passwords</tt></i> parameter is set in the
  69                         <a href="smb.conf.5.html"><span class="citerefentry"><span class="refentrytitle">smb.conf</span>(5)</span></a> config file. </p></li><li><p><span class="emphasis"><em>D</em></span> - This means the account
  70                         is disabled and no SMB/CIFS logins  will be allowed for this user. </p></li><li><p><span class="emphasis"><em>W</em></span> - This means this account
  71                         is a "Workstation Trust" account. This kind of account is used
  72                         in the Samba PDC code stream to allow Windows NT Workstations
  73                         and Servers to join a Domain hosted by a Samba PDC. </p></li></ul></div><p>Other flags may be added as the code is extended in future.
  74                 The rest of this field space is filled in with spaces. </p></dd><dt><span class="term">Last Change Time</span></dt><dd><p>This field consists of the time the account was
  75                 last modified. It consists of the characters 'LCT-' (standing for
  76                 "Last Change Time") followed by a numeric encoding of the UNIX time
  77                 in seconds since the epoch (1970) that the last change was made.
  78                 </p></dd></dl></div><p>All other colon separated fields are ignored at this time.</p></div><div class="refsect1" lang="en"><h2>VERSION</h2><p>This man page is correct for version 3.0 of
  79         the Samba suite.</p></div><div class="refsect1" lang="en"><h2>SEE ALSO</h2><p><a href="smbpasswd.8.html"><span class="citerefentry"><span class="refentrytitle">smbpasswd</span>(8)</span></a>, <a href="Samba.7.html"><span class="citerefentry"><span class="refentrytitle">Samba</span>(7)</span></a>, and
  80         the Internet RFC1321 for details on the MD4 algorithm.
  81         </p></div><div class="refsect1" lang="en"><h2>AUTHOR</h2><p>The original Samba software and related utilities
  82         were created by Andrew Tridgell. Samba is now developed
  83         by the Samba Team as an Open Source project similar
  84         to the way the Linux kernel is developed.</p><p>The original Samba man pages were written by Karl Auer.
  85         The man page sources were converted to YODL format (another
  86         excellent piece of Open Source software, available at <ulink url="ftp://ftp.icce.rug.nl/pub/unix/">
  87         ftp://ftp.icce.rug.nl/pub/unix/</ulink>) and updated for the Samba 2.0
  88         release by Jeremy Allison.  The conversion to DocBook for
  89         Samba 2.2 was done by Gerald Carter. The conversion to DocBook XML 4.2
  90         for Samba 3.0 was done by Alexander Bokovoy.</p></div></div></body></html>