mailto(samba@samba.org) manpage(smbpasswd htmlcommand((5)))(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. If this does not match then Samba will refuse to recognize this bf(smbpasswd) file entry as being valid for a user. 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 (i.e. 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 on 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 (i.e. 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 on 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, i.e. an ordinary user. Only bf(User) and link(bf(Workstation 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 disabled 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 email(samba@samba.org). 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, available at url(bf(ftp://ftp.icce.rug.nl/pub/unix/))(ftp://ftp.icce.rug.nl/pub/unix/)) and updated for the Samba2.0 release by Jeremy Allison, email(samba@samba.org). 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.