| 1 | '\" t
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| 2 | .\" Title: smbpasswd
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| 3 | .\" Author: [see the "AUTHOR" section]
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| 4 | .\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/>
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| 5 | .\" Date: 01/14/2010
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| 6 | .\" Manual: File Formats and Conventions
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| 7 | .\" Source: Samba 3.3
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| 8 | .\" Language: English
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| 9 | .\"
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| 10 | .TH "SMBPASSWD" "5" "01/14/2010" "Samba 3\&.3" "File Formats and Conventions"
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| 11 | .\" -----------------------------------------------------------------
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| 12 | .\" * set default formatting
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| 13 | .\" -----------------------------------------------------------------
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| 14 | .\" disable hyphenation
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| 15 | .nh
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| 16 | .\" disable justification (adjust text to left margin only)
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| 17 | .ad l
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| 18 | .\" -----------------------------------------------------------------
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| 19 | .\" * MAIN CONTENT STARTS HERE *
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| 20 | .\" -----------------------------------------------------------------
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| 21 | .SH "NAME"
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| 22 | smbpasswd \- The Samba encrypted password file
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| 23 | .SH "SYNOPSIS"
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| 24 | .PP
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| 25 | smbpasswd
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| 26 | .SH "DESCRIPTION"
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| 27 | .PP
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| 28 | This tool is part of the
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| 29 | \fBsamba\fR(7)
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| 30 | suite\&.
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| 31 | .PP
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| 32 | 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\&.
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| 33 | .SH "FILE FORMAT"
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| 34 | .PP
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| 35 | The format of the smbpasswd file used by Samba 2\&.2 is very similar to the familiar Unix
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| 36 | passwd(5)
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| 37 | 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:
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| 38 | .PP
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| 39 | name
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| 40 | .RS 4
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| 41 | This is the user name\&. It must be a name that already exists in the standard UNIX passwd file\&.
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| 42 | .RE
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| 43 | .PP
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| 44 | uid
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| 45 | .RS 4
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| 46 | 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\&.
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| 47 | .RE
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| 48 | .PP
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| 49 | Lanman Password Hash
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| 50 | .RS 4
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| 51 | 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
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| 52 | \fBdisabled\fR
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| 53 | and the user will not be able to log onto the Samba server\&.
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| 54 | .sp
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| 55 | \fIWARNING !!\fR
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| 56 | 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
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| 57 | \fIplain text equivalents\fR
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| 58 | and must
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| 59 | \fINOT\fR
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| 60 | 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\&.
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| 61 | .RE
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| 62 | .PP
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| 63 | NT Password Hash
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| 64 | .RS 4
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| 65 | 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\&.
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| 66 | .sp
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| 67 | 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)\&.
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