1<?xml version="1.0" encoding="iso-8859-1"?> 2<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc"> 3<refentry id="smbpasswd.5"> 4 5<refmeta> 6 <refentrytitle>smbpasswd</refentrytitle> 7 <manvolnum>5</manvolnum> 8 <refmiscinfo class="source">Samba</refmiscinfo> 9 <refmiscinfo class="manual">File Formats and Conventions</refmiscinfo> 10 <refmiscinfo class="version">3.5</refmiscinfo> 11</refmeta> 12 13 14<refnamediv> 15 <refname>smbpasswd</refname> 16 <refpurpose>The Samba encrypted password file</refpurpose> 17</refnamediv> 18 19<refsynopsisdiv> 20 <para><filename>smbpasswd</filename></para> 21</refsynopsisdiv> 22 23<refsect1> 24 <title>DESCRIPTION</title> 25 26 <para>This tool is part of the <citerefentry><refentrytitle>samba</refentrytitle> 27 <manvolnum>7</manvolnum></citerefentry> suite.</para> 28 29 <para>smbpasswd is the Samba encrypted password file. It contains 30 the username, Unix user id and the SMB hashed passwords of the 31 user, as well as account flag information and the time the 32 password was last changed. This file format has been evolving with 33 Samba and has had several different formats in the past. </para> 34</refsect1> 35 36<refsect1> 37 <title>FILE FORMAT</title> 38 39 <para>The format of the smbpasswd file used by Samba 2.2 40 is very similar to the familiar Unix <filename>passwd(5)</filename> 41 file. It is an ASCII file containing one line for each user. Each field 42 ithin each line is separated from the next by a colon. Any entry 43 beginning with '#' is ignored. The smbpasswd file contains the 44 following information for each user: </para> 45 46 <variablelist> 47 <varlistentry> 48 <term>name</term> 49 <listitem><para> This is the user name. It must be a name that 50 already exists in the standard UNIX passwd file. </para> 51 </listitem> 52 </varlistentry> 53 54 <varlistentry> 55 <term>uid</term> 56 <listitem><para>This is the UNIX uid. It must match the uid 57 field for the same user entry in the standard UNIX passwd file. 58 If this does not match then Samba will refuse to recognize 59 this smbpasswd file entry as being valid for a user. 60 </para></listitem> 61 </varlistentry> 62 63 64 <varlistentry> 65 <term>Lanman Password Hash</term> 66 <listitem><para>This is the LANMAN hash of the user's password, 67 encoded as 32 hex digits. The LANMAN hash is created by DES 68 encrypting a well known string with the user's password as the 69 DES key. This is the same password used by Windows 95/98 machines. 70 Note that this password hash is regarded as weak as it is 71 vulnerable to dictionary attacks and if two users choose the 72 same password this entry will be identical (i.e. the password 73 is not "salted" as the UNIX password is). If the user has a 74 null password this field will contain the characters "NO PASSWORD" 75 as the start of the hex string. If the hex string is equal to 76 32 'X' characters then the user's account is marked as 77 <constant>disabled</constant> and the user will not be able to 78 log onto the Samba server. </para> 79 80 <para><emphasis>WARNING !!</emphasis> Note that, due to 81 the challenge-response nature of the SMB/CIFS authentication 82 protocol, anyone with a knowledge of this password hash will 83 be able to impersonate the user on the network. For this 84 reason these hashes are known as <emphasis>plain text 85 equivalents</emphasis> and must <emphasis>NOT</emphasis> be made 86 available to anyone but the root user. To protect these passwords 87 the smbpasswd file is placed in a directory with read and 88 traverse access only to the root user and the smbpasswd file 89 itself must be set to be read/write only by root, with no 90 other access. </para></listitem> 91 </varlistentry> 92 93 94 <varlistentry> 95 <term>NT Password Hash</term> 96 <listitem><para>This is the Windows NT hash of the user's 97 password, encoded as 32 hex digits. The Windows NT hash is 98 created by taking the user's password as represented in 99 16-bit, little-endian UNICODE and then applying the MD4 100 (internet rfc1321) hashing algorithm to it. </para> 101 102 <para>This password hash is considered more secure than 103 the LANMAN Password Hash as it preserves the case of the 104 password and uses a much higher quality hashing algorithm. 105 However, it is still the case that if two users choose the same 106 password this entry will be identical (i.e. the password is 107 not "salted" as the UNIX password is). </para> 108 109 <para><emphasis>WARNING !!</emphasis>. Note that, due to 110 the challenge-response nature of the SMB/CIFS authentication 111 protocol, anyone with a knowledge of this password hash will 112 be able to impersonate the user on the network. For this 113 reason these hashes are known as <emphasis>plain text 114 equivalents</emphasis> and must <emphasis>NOT</emphasis> be made 115 available to anyone but the root user. To protect these passwords 116 the smbpasswd file is placed in a directory with read and 117 traverse access only to the root user and the smbpasswd file 118 itself must be set to be read/write only by root, with no 119 other access. </para></listitem> 120 </varlistentry> 121 122 123 <varlistentry> 124 <term>Account Flags</term> 125 <listitem><para>This section contains flags that describe 126 the attributes of the users account. This field is bracketed by 127 '[' and ']' characters and is always 13 characters in length 128 (including the '[' and ']' characters). 129 The contents of this field may be any of the following characters: 130 </para> 131 132 <itemizedlist> 133 <listitem><para><emphasis>U</emphasis> - This means 134 this is a "User" account, i.e. an ordinary user.</para></listitem> 135 136 <listitem><para><emphasis>N</emphasis> - This means the 137 account has no password (the passwords in the fields LANMAN 138 Password Hash and NT Password Hash are ignored). Note that this 139 will only allow users to log on with no password if the <parameter> 140 null passwords</parameter> parameter is set in the 141 <citerefentry><refentrytitle>smb.conf</refentrytitle> 142 <manvolnum>5</manvolnum></citerefentry> config file. </para></listitem> 143 144 <listitem><para><emphasis>D</emphasis> - This means the account 145 is disabled and no SMB/CIFS logins will be allowed for this user. </para></listitem> 146 147 <listitem><para><emphasis>X</emphasis> - This means the password 148 does not expire. </para></listitem> 149 150 <listitem><para><emphasis>W</emphasis> - This means this account 151 is a "Workstation Trust" account. This kind of account is used 152 in the Samba PDC code stream to allow Windows NT Workstations 153 and Servers to join a Domain hosted by a Samba PDC. </para> 154 </listitem> 155 </itemizedlist> 156 157 <para>Other flags may be added as the code is extended in future. 158 The rest of this field space is filled in with spaces. For further 159 information regarding the flags that are supported please refer to the 160 man page for the <command>pdbedit</command> command.</para> 161 </listitem> 162 </varlistentry> 163 164 165 <varlistentry> 166 <term>Last Change Time</term> 167 <listitem><para>This field consists of the time the account was 168 last modified. It consists of the characters 'LCT-' (standing for 169 "Last Change Time") followed by a numeric encoding of the UNIX time 170 in seconds since the epoch (1970) that the last change was made. 171 </para></listitem> 172 </varlistentry> 173 </variablelist> 174 175 <para>All other colon separated fields are ignored at this time.</para> 176</refsect1> 177 178<refsect1> 179 <title>VERSION</title> 180 181 <para>This man page is correct for version 3 of 182 the Samba suite.</para> 183</refsect1> 184 185<refsect1> 186 <title>SEE ALSO</title> 187 <para><citerefentry><refentrytitle>smbpasswd</refentrytitle> 188 <manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>Samba</refentrytitle> 189 <manvolnum>7</manvolnum></citerefentry>, and 190 the Internet RFC1321 for details on the MD4 algorithm. 191 </para> 192</refsect1> 193 194<refsect1> 195 <title>AUTHOR</title> 196 197 <para>The original Samba software and related utilities 198 were created by Andrew Tridgell. Samba is now developed 199 by the Samba Team as an Open Source project similar 200 to the way the Linux kernel is developed.</para> 201 202 <para>The original Samba man pages were written by Karl Auer. 203 The man page sources were converted to YODL format (another 204 excellent piece of Open Source software, available at <ulink noescape="1" url="ftp://ftp.icce.rug.nl/pub/unix/"> 205 ftp://ftp.icce.rug.nl/pub/unix/</ulink>) and updated for the Samba 2.0 206 release by Jeremy Allison. The conversion to DocBook for 207 Samba 2.2 was done by Gerald Carter. The conversion to DocBook XML 4.2 208 for Samba 3.0 was done by Alexander Bokovoy.</para> 209</refsect1> 210 211</refentry> 212