samba-mirror/docs/manpages/smbpasswd.5

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.TH "SMBPASSWD" "5" "04 March 2003" "" ""
.SH NAME
smbpasswd \- The Samba encrypted password file
.SH SYNOPSIS
.PP
\fIsmbpasswd\fR
.SH "DESCRIPTION"
.PP
This tool is part of the  Samba 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 \fIpasswd(5)\fR 
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: 
.TP
\fBname\fR
This is the user name. It must be a name that 
already exists in the standard UNIX passwd file. 
.TP
\fBuid\fR
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. 
.TP
\fBLanman Password Hash\fR
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. 

\fBWARNING !!\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 \fBplain text 
equivalents\fR and must \fBNOT\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. 
.TP
\fBNT Password Hash\fR
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). 

\fBWARNING !!\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 \fBplain text 
equivalents\fR and must \fBNOT\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. 
.TP
\fBAccount Flags\fR
This section contains flags that describe 
the attributes of the users account. In the Samba 2.2 release 
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 characters.
.RS
.TP 0.2i
\(bu
\fBU\fR - This means 
this is a "User" account, i.e. an ordinary user. Only User 
and Workstation Trust accounts are currently supported 
in the smbpasswd file. 
.TP 0.2i
\(bu
\fBN\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 \fIsmb.conf(5)
\fR config file. 
.TP 0.2i
\(bu
\fBD\fR - This means the account 
is disabled and no SMB/CIFS logins  will be allowed for 
this user. 
.TP 0.2i
\(bu
\fBW\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. 
.RE

Other flags may be added as the code is extended in future.
The rest of this field space is filled in with spaces. 
.TP
\fBLast Change Time\fR
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. 
.PP
All other colon separated fields are ignored at this time.
.SH "VERSION"
.PP
This man page is correct for version 3.0 of 
the Samba suite.
.SH "SEE ALSO"
.PP
\fBsmbpasswd(8)\fR 
samba(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/ <URL: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