'\" t .\" Title: smbpasswd .\" Author: [see the "AUTHOR" section] .\" Generator: DocBook XSL Stylesheets vsnapshot .\" Date: 04/08/2024 .\" Manual: File Formats and Conventions .\" Source: Samba 4.19.6-Debian .\" Language: English .\" .TH "SMBPASSWD" "5" "04/08/2024" "Samba 4\&.19\&.6\-Debian" "File Formats and Conventions" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" smbpasswd \- The Samba encrypted password file .SH "SYNOPSIS" .PP smbpasswd .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 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 \*(Aq#\*(Aq 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\*(Aqs password, encoded as 32 hex digits\&. The LANMAN hash is created by DES encrypting a well known string with the user\*(Aqs 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 \*(AqX\*(Aq characters then the user\*(Aqs 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\*(Aqs password, encoded as 32 hex digits\&. The Windows NT hash is created by taking the user\*(Aqs 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 \*(Aq[\*(Aq and \*(Aq]\*(Aq characters and is always 13 characters in length (including the \*(Aq[\*(Aq and \*(Aq]\*(Aq characters)\&. The contents of this field may be any of the following characters: .RS .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\&. .RE .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 pdbedit command\&. .RE .PP Last Change Time .RS 4 This field consists of the time the account was last modified\&. It consists of the characters \*(AqLCT\-\*(Aq (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 part of version 4\&.19\&.6\-Debian 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\&.