1 2 3 4 5 6 7<html><head><title>smbpasswd (5)</title> 8 9<link rev="made" href="mailto:samba@samba.org"> 10</head> 11<body> 12 13<hr> 14 15<h1>smbpasswd (5)</h1> 16<h2>Samba</h2> 17<h2>23 Oct 1998</h2> 18 19 20 21<p><a name="NAME"></a> 22<h2>NAME</h2> 23 smbpasswd - The Samba encrypted password file 24<p><a name="SYNOPSIS"></a> 25<h2>SYNOPSIS</h2> 26 27<p>smbpasswd is the <strong>Samba</strong> encrypted password file. 28<p><a name="DESCRIPTION"></a> 29<h2>DESCRIPTION</h2> 30 31<p>This file is part of the <strong>Samba</strong> suite. 32<p>smbpasswd is the <strong>Samba</strong> encrypted password file. It contains 33the username, Unix user id and the SMB hashed passwords of the 34user, as well as account flag information and the time the password 35was last changed. This file format has been evolving with Samba 36and has had several different formats in the past. 37<p><a name="FILEFORMAT"></a> 38<h2>FILE FORMAT</h2> 39 40<p>The format of the smbpasswd file used by Samba 2.0 is very similar to 41the familiar Unix <strong>passwd (5)</strong> file. It is an ASCII file containing 42one line for each user. Each field within each line is separated from 43the next by a colon. Any entry beginning with # is ignored. The 44smbpasswd file contains the following information for each user: 45<p><dl> 46<p><a name="name"></a> 47<p></p><dt><strong><strong>name</strong></strong><dd> <br> <br> 48<p>This is the user name. It must be a name that already exists 49 in the standard UNIX passwd file. 50<p><a name="uid"></a> 51<p></p><dt><strong><strong>uid</strong></strong><dd> <br> <br> 52<p>This is the UNIX uid. It must match the uid field for the same 53 user entry in the standard UNIX passwd file. If this does not 54 match then Samba will refuse to recognize this <strong>smbpasswd</strong> file entry 55 as being valid for a user. 56<p><a name="LanmanPasswordHash"></a> 57<p></p><dt><strong><strong>Lanman Password Hash</strong></strong><dd> <br> <br> 58<p>This is the <em>LANMAN</em> hash of the users password, encoded as 32 hex 59 digits. The <em>LANMAN</em> hash is created by DES encrypting a well known 60 string with the users password as the DES key. This is the same 61 password used by Windows 95/98 machines. Note that this password hash 62 is regarded as weak as it is vulnerable to dictionary attacks and if 63 two users choose the same password this entry will be identical (i.e. 64 the password is not <em>"salted"</em> as the UNIX password is). If the 65 user has a null password this field will contain the characters 66 <code>"NO PASSWORD"</code> as the start of the hex string. If the hex string 67 is equal to 32 <code>'X'</code> characters then the users account is marked as 68 <em>disabled</em> and the user will not be able to log onto the Samba 69 server. 70<p><em>WARNING !!</em>. Note that, due to the challenge-response nature of the 71 SMB/CIFS authentication protocol, anyone with a knowledge of this 72 password hash will be able to impersonate the user on the network. 73 For this reason these hashes are known as <em>"plain text equivalent"</em> 74 and must <em>NOT</em> be made available to anyone but the root user. To 75 protect these passwords the <strong>smbpasswd</strong> file is placed in a 76 directory with read and traverse access only to the root user and the 77 <strong>smbpasswd</strong> file itself must be set to be read/write only by root, 78 with no other access. 79<p><a name="NTPasswordHash"></a> 80<p></p><dt><strong><strong>NT Password Hash</strong></strong><dd> <br> <br> 81<p>This is the <em>Windows NT</em> hash of the users password, encoded as 32 82 hex digits. The <em>Windows NT</em> hash is created by taking the users 83 password as represented in 16-bit, little-endian UNICODE and then 84 applying the <em>MD4</em> (internet rfc1321) hashing algorithm to it. 85<p>This password hash is considered more secure than the <a href="smbpasswd.5.html#LanmanPasswordHash"><strong>Lanman 86 Password Hash</strong></a> as it preserves the case of the 87 password and uses a much higher quality hashing algorithm. However, it 88 is still the case that if two users choose the same password this 89 entry will be identical (i.e. the password is not <em>"salted"</em> as the 90 UNIX password is). 91<p><em>WARNING !!</em>. Note that, due to the challenge-response nature of the 92 SMB/CIFS authentication protocol, anyone with a knowledge of this 93 password hash will be able to impersonate the user on the network. 94 For this reason these hashes are known as <em>"plain text equivalent"</em> 95 and must <em>NOT</em> be made available to anyone but the root user. To 96 protect these passwords the <strong>smbpasswd</strong> file is placed in a 97 directory with read and traverse access only to the root user and the 98 <strong>smbpasswd</strong> file itself must be set to be read/write only by root, 99 with no other access. 100<p><a name="AccountFlags"></a> 101<p></p><dt><strong><strong>Account Flags</strong></strong><dd> <br> <br> 102<p>This section contains flags that describe the attributes of the users 103 account. In the <strong>Samba2.0</strong> release this field is bracketed by <code>'['</code> 104 and <code>']'</code> characters and is always 13 characters in length (including 105 the <code>'['</code> and <code>']'</code> characters). The contents of this field may be 106 any of the characters. 107<p><dl> 108<p><a name="capU"></a> 109 <li > <strong>'U'</strong> This means this is a <em>"User"</em> account, i.e. an ordinary 110 user. Only <strong>User</strong> and <a href="smbpasswd.5.html#capW"><strong>Workstation Trust</strong></a> accounts are 111 currently supported in the <strong>smbpasswd</strong> file. 112<p><a name="capN"></a> 113 <li > <strong>'N'</strong> This means the account has <em>no</em> password (the passwords 114 in the fields <a href="smbpasswd.5.html#LanmanPasswordHash"><strong>Lanman Password Hash</strong></a> and 115 <a href="smbpasswd.5.html#NTPasswordHash"><strong>NT Password Hash</strong></a> are ignored). Note that this 116 will only allow users to log on with no password if the 117 <a href="smb.conf.5.html#nullpasswords"><strong>null passwords</strong></a> parameter is set 118 in the <a href="smb.conf.5.html"><strong>smb.conf (5)</strong></a> config file. 119<p><a name="capD"></a> 120 <li > <strong>'D'</strong> This means the account is disabled and no SMB/CIFS logins 121 will be allowed for this user. 122<p><a name="capW"></a> 123 <li > <strong>'W'</strong> This means this account is a <em>"Workstation Trust"</em> account. 124 This kind of account is used in the Samba PDC code stream to allow Windows 125 NT Workstations and Servers to join a Domain hosted by a Samba PDC. 126<p></dl> 127<p>Other flags may be added as the code is extended in future. The rest of 128 this field space is filled in with spaces. 129<p><a name="LastChangeTime"></a> 130<p></p><dt><strong><strong>Last Change Time</strong></strong><dd> <br> <br> 131<p>This field consists of the time the account was last modified. It consists of 132 the characters <code>LCT-</code> (standing for <em>"Last Change Time"</em>) followed by a numeric 133 encoding of the UNIX time in seconds since the epoch (1970) that the last change 134 was made. 135<p><p></p><dt><strong><strong>Following fields</strong></strong><dd> <br> <br> 136<p>All other colon separated fields are ignored at this time. 137<p></dl> 138<p><a name="NOTES"></a> 139<h2>NOTES</h2> 140 141<p>In previous versions of Samba (notably the 1.9.18 series) this file 142did not contain the <a href="smbpasswd.5.html#AccountFlags"><strong>Account Flags</strong></a> or 143<a href="smbpasswd.5.html#LastChangeTime"><strong>Last Change Time</strong></a> fields. The Samba 2.0 144code will read and write these older password files but will not be able to 145modify the old entries to add the new fields. New entries added with 146<a href="smbpasswd.8.html"><strong>smbpasswd (8)</strong></a> will contain the new fields 147in the added accounts however. Thus an older <strong>smbpasswd</strong> file used 148with Samba 2.0 may end up with some accounts containing the new fields 149and some not. 150<p>In order to convert from an old-style <strong>smbpasswd</strong> file to a new 151style, run the script <strong>convert_smbpasswd</strong>, installed in the 152Samba <code>bin/</code> directory (the same place that the <a href="smbd.8.html"><strong>smbd</strong></a> 153and <a href="nmbd.8.html"><strong>nmbd</strong></a> binaries are installed) as follows: 154<p><pre> 155 156 157 cat old_smbpasswd_file | convert_smbpasswd > new_smbpasswd_file 158 159 160</pre> 161 162<p>The <strong>convert_smbpasswd</strong> script reads from stdin and writes to stdout 163so as not to overwrite any files by accident. 164<p>Once this script has been run, check the contents of the new smbpasswd 165file to ensure that it has not been damaged by the conversion script 166(which uses <strong>awk</strong>), and then replace the <code><old smbpasswd file></code> 167with the <code><new smbpasswd file></code>. 168<p><a name="VERSION"></a> 169<h2>VERSION</h2> 170 171<p>This man page is correct for version 2.0 of the Samba suite. 172<p><a name="SEEALSO"></a> 173<h2>SEE ALSO</h2> 174 175<p><a href="smbpasswd.8.html"><strong>smbpasswd (8)</strong></a>, <a href="samba.7.html"><strong>samba 176(7)</strong></a>, and the Internet RFC1321 for details on the MD4 177algorithm. 178<p><a name="AUTHOR"></a> 179<h2>AUTHOR</h2> 180 181<p>The original Samba software and related utilities were created by 182Andrew Tridgell <a href="mailto:samba@samba.org"><em>samba@samba.org</em></a>. Samba is now developed 183by the Samba Team as an Open Source project similar to the way the 184Linux kernel is developed. 185<p>The original Samba man pages were written by Karl Auer. The man page 186sources were converted to YODL format (another excellent piece of Open 187Source software, available at 188<a href="ftp://ftp.icce.rug.nl/pub/unix/"><strong>ftp://ftp.icce.rug.nl/pub/unix/</strong></a>) 189and updated for the Samba2.0 release by Jeremy 190Allison, <a href="mailto:samba@samba.org"><em>samba@samba.org</em></a>. 191<p>See <a href="samba.7.html"><strong>samba (7)</strong></a> to find out how to get a full 192list of contributors and details on how to submit bug reports, 193comments etc. 194</body> 195</html> 196