path: root/docs/manpages/smbpasswd.5

.\"     Title: smbpasswd
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.74.0 <http://docbook.sf.net/>
.\"      Date: 06/18/2010
.\"    Manual: File Formats and Conventions
.\"    Source: Samba 3.5
.\"  Language: English
.\"
.TH "SMBPASSWD" "5" "06/18/2010" "Samba 3\&.5" "File Formats and Conventions"
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.SH "Name"
smbpasswd \- The Samba encrypted password file
.SH "Synopsis"
.PP
\FCsmbpasswd\F[]
.SH "DESCRIPTION"
.PP
This tool is part of the
\fBsamba\fR(7)
suite\&.
.PP
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\&.
.SH "FILE FORMAT"
.PP
The format of the smbpasswd file used by Samba 2\&.2 is very similar to the familiar Unix
\FCpasswd(5)\F[]
file\&. It is an ASCII file containing one line for each user\&. Each field ithin 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:
.PP
name
.RS 4
This is the user name\&. It must be a name that already exists in the standard UNIX passwd file\&.
.RE
.PP
uid
.RS 4
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\&.
.RE
.PP
Lanman Password Hash
.RS 4
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
\fBdisabled\fR
and the user will not be able to log onto the Samba server\&.
.sp
\fIWARNING !!\fR
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
\fIplain text equivalents\fR
and must
\fINOT\fR
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\&.
.RE
.PP
NT Password Hash
.RS 4
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\&.
.sp
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)\&.
.sp
\fIWARNING !!\fR\&. 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
\fIplain text equivalents\fR
and must
\fINOT\fR
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\&.
.RE
.PP
Account Flags
.RS 4
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:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIU\fR
\- This means this is a "User" account, i\&.e\&. an ordinary user\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIN\fR
\- 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
\fI null passwords\fR
parameter is set in the
\fBsmb.conf\fR(5)
config file\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fID\fR
\- This means the account is disabled and no SMB/CIFS logins will be allowed for this user\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIX\fR
\- This means the password does not expire\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIW\fR
\- 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\&.
.sp
.RE
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
\FCpdbedit\F[]
command\&.
.RE
.PP
Last Change Time
.RS 4
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\&.
.RE
.PP
All other colon separated fields are ignored at this time\&.
.SH "VERSION"
.PP
This man page is correct for version 3 of the Samba suite\&.
.SH "SEE ALSO"
.PP
\fBsmbpasswd\fR(8),
\fBSamba\fR(7), and the Internet RFC1321 for details on the MD4 algorithm\&.
.SH "AUTHOR"
.PP
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\&.
.PP
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\&.