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mailto(samba-bugs@samba.anu.edu.au)
manpage(smbpasswd)(5)(23 Oct 1998)(Samba)(SAMBA)
label(NAME)
manpagename(smbpasswd)(The Samba encrypted password file)
label(SYNOPSIS)
manpagesynopsis()
smbpasswd is the bf(Samba) encrypted password file.
label(DESCRIPTION)
manpagedescription()
This file is part of the bf(Samba) suite.
smbpasswd is the bf(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.
label(FILEFORMAT)
manpagesection(FILE FORMAT)
The format of the smbpasswd file used by Samba 2.0 is very similar to
the familiar unix bf(passwd (5)) file. It is an ASCII file containing
one line for each user. Each field within 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:
startit()
label(name)
dit(bf(name)) nl() nl()
This is the user name. It must be a name that already exists
in the standard UNIX passwd file.
label(uid)
dit(bf(uid)) nl() nl()
This is the UNIX uid. It must match the uid field for the same
user entry in the standard UNIX passwd file.
label(LanmanPasswordHash)
dit(bf(Lanman Password Hash)) nl() nl()
This is the em(LANMAN) hash of the users password, encoded as 32 hex
digits. The em(LANMAN) hash is created by DES encrypting a well known
string with the users 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 (ie.
the password is not em("salted") as the UNIX password is). If the
user has a null password this field will contain the characters
tt("NO PASSWORD") as the start of the hex string. If the hex string
is equal to 32 tt('X') characters then the users account is marked as
em(disabled) and the user will not be able to log onto the Samba
server.
em(WARNING !!). 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 of the network.
For this reason these hashes are known as em("plain text equivalent")
and must em(NOT) be made available to anyone but the root user. To
protect these passwords the bf(smbpasswd) file is placed in a
directory with read and traverse access only to the root user and the
bf(smbpasswd) file itself must be set to be read/write only by root,
with no other access.
label(NTPasswordHash)
dit(bf(NT Password Hash)) nl() nl()
This is the em(Windows NT) hash of the users password, encoded as 32
hex digits. The em(Windows NT) hash is created by taking the users
password as represented in 16-bit, little-endian UNICODE and then
applying the em(MD4) (internet rfc1321) hashing algorithm to it.
This password hash is considered more secure than the link(bf(Lanman
Password Hash))(LanmanPasswordHash) 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 (ie. the password is not em("salted") as the
UNIX password is).
em(WARNING !!). 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 of the network.
For this reason these hashes are known as em("plain text equivalent")
and must em(NOT) be made available to anyone but the root user. To
protect these passwords the bf(smbpasswd) file is placed in a
directory with read and traverse access only to the root user and the
bf(smbpasswd) file itself must be set to be read/write only by root,
with no other access.
label(AccountFlags)
dit(bf(Account Flags)) nl() nl()
This section contains flags that describe the attributes of the users
account. In the bf(Samba2.0) release this field is bracketed by tt('[')
and tt(']') characters and is always 13 characters in length (including
the tt('[') and tt(']') characters). The contents of this field may be
any of the characters.
startit()
label(capU)
it() bf('U') This means this is a em("User") account, ie. an ordinary
user. Only bf(User) and link(bf(Worskstation Trust))(capW) accounts are
currently supported in the bf(smbpasswd) file.
label(capN)
it() bf('N') This means the account has em(no) password (the passwords
in the fields link(bf(Lanman Password Hash))(LanmanPasswordHash) and
link(bf(NT Password Hash))(NTPasswordHash) are ignored). Note that this
will only allow users to log on with no password if the
url(bf(null passwords))(smb.conf.5.html#nullpasswords) parameter is set
in the url(bf(smb.conf (5)))(smb.conf.5.html) config file.
label(capD)
it() bf('D') This means the account is diabled and no SMB/CIFS logins
will be allowed for this user.
label(capW)
it() bf('W') This means this account is a em("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.
endit()
Other flags may be added as the code is extended in future. The rest of
this field space is filled in with spaces.
label(LastChangeTime)
dit(bf(Last Change Time)) nl() nl()
This field consists of the time the account was last modified. It consists of
the characters tt(LCT-) (standing for em("Last Change Time")) followed by a numeric
encoding of the UNIX time in seconds since the epoch (1970) that the last change
was made.
dit(bf(Following fields)) nl() nl()
All other colon separated fields are ignored at this time.
enddit()
label(NOTES)
manpagesection(NOTES)
In previous versions of Samba (notably the 1.9.18 series) this file
did not contain the link(bf(Account Flags))(AccountFlags) or
link(bf(Last Change Time))(LastChangeTime) fields. The Samba 2.0
code will read and write these older password files but will not be able to
modify the old entries to add the new fields. New entries added with
url(bf(smbpasswd (8)))(smbpasswd.8.html) will contain the new fields
in the added accounts however. Thus an older bf(smbpasswd) file used
with Samba 2.0 may end up with some accounts containing the new fields
and some not.
In order to convert from an old-style bf(smbpasswd) file to a new
style, run the script bf(convert_smbpasswd), installed in the
Samba tt(bin/) directory (the same place that the url(bf(smbd))(smbd.8.html)
and url(bf(nmbd))(nmbd.8.html) binaries are installed) as follows:
verb(
cat old_smbpasswd_file | convert_smbpasswd > new_smbpasswd_file
)
The bf(convert_smbpasswd) script reads from stdin and writes to stdout
so as not to overwrite any files by accident.
Once this script has been run, check the contents of the new smbpasswd
file to ensure that it has not been damaged by the conversion script
(which uses bf(awk)), and then replace the tt(<old smbpasswd file>)
with the tt(<new smbpasswd file>).
label(VERSION)
manpagesection(VERSION)
This man page is correct for version 2.0 of the Samba suite.
label(SEEALSO)
manpageseealso()
url(bf(smbpasswd (8)))(smbpasswd.8.html), url(bf(samba
(7)))(samba.7.html), and the Internet RFC1321 for details on the MD4
algorithm.
label(AUTHOR)
manpageauthor()
The original Samba software and related utilities were created by
Andrew Tridgell (samba-bugs@samba.anu.edu.au). Samba is now developed
by the Samba Team as an Open Source project similar to the way the
Linux kernel is developed.
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) and updated for the Samba2.0 release by Jeremy
Allison, email(samba-bugs@samba.anu.edu.au).
See url(bf(samba (7)))(samba.7.html) to find out how to get a full
list of contributors and details on how to submit bug reports,
comments etc.
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