1SMBPASSWD(5) SMBPASSWD(5)
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6 smbpasswd - The Samba encrypted password file
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9 smbpasswd
10
12 This tool is part of the samba(7) suite.
13 smbpasswd is the Samba encrypted password file. It contains the user‐
15 name, Unix user id and the SMB hashed passwords of the user, as well as
16 account flag information and the time the password was last changed.
17 This file format has been evolving with Samba and has had several dif‐
18 ferent formats in the past.
19
21 The format of the smbpasswd file used by Samba 2.2 is very similar to
22 the familiar Unix passwd(5) file. It is an ASCII file containing one
23 line for each user. Each field ithin each line is separated from the
24 next by a colon. Any entry beginning with '#' is ignored. The smbpasswd
25 file contains the following information for each user:
26 name
28 This is the user name. It must be a name that already exists in the
29 standard UNIX passwd file.
30 uid
32 This is the UNIX uid. It must match the uid field for the same user
33 entry in the standard UNIX passwd file. If this does not match then
34 Samba will refuse to recognize this smbpasswd file entry as being
35 valid for a user.
36 Lanman Password Hash
38 This is the LANMAN hash of the user's password, encoded as 32 hex
39 digits. The LANMAN hash is created by DES encrypting a well known
40 string with the user's password as the DES key. This is the same
41 password used by Windows 95/98 machines. Note that this password
42 hash is regarded as weak as it is vulnerable to dictionary attacks
43 and if two users choose the same password this entry will be identi‐
44 cal (i.e. the password is not "salted" as the UNIX password is). If
45 the user has a null password this field will contain the characters
46 "NO PASSWORD" as the start of the hex string. If the hex string is
47 equal to 32 'X' characters then the user's account is marked as dis‐
48 abled and the user will not be able to log onto the Samba server.
49 WARNING !! Note that, due to the challenge-response nature of the
51 SMB/CIFS authentication protocol, anyone with a knowledge of this
52 password hash will be able to impersonate the user on the network.
53 For this reason these hashes are known as plain text equivalents and
54 must NOT be made available to anyone but the root user. To protect
55 these passwords the smbpasswd file is placed in a directory with
56 read and traverse access only to the root user and the smbpasswd
57 file itself must be set to be read/write only by root, with no other
58 access.
59 NT Password Hash
61 This is the Windows NT hash of the user's password, encoded as 32
62 hex digits. The Windows NT hash is created by taking the user's
63 password as represented in 16-bit, little-endian UNICODE and then
64 applying the MD4 (internet rfc1321) hashing algorithm to it.
65 This password hash is considered more secure than the LANMAN Pass‐
67 word Hash as it preserves the case of the password and uses a much
68 higher quality hashing algorithm. However, it is still the case that
69 if two users choose the same password this entry will be identical
70 (i.e. the password is not "salted" as the UNIX password is).
71 WARNING !!. Note that, due to the challenge-response nature of the
73 SMB/CIFS authentication protocol, anyone with a knowledge of this
74 password hash will be able to impersonate the user on the network.
75 For this reason these hashes are known as plain text equivalents and
76 must NOT be made available to anyone but the root user. To protect
77 these passwords the smbpasswd file is placed in a directory with
78 read and traverse access only to the root user and the smbpasswd
79 file itself must be set to be read/write only by root, with no other
80 access.
81 Account Flags
83 This section contains flags that describe the attributes of the
84 users account. This field is bracketed by '[' and ']' characters and
85 is always 13 characters in length (including the '[' and ']' charac‐
86 ters). The contents of this field may be any of the following char‐
87 acters:
88 · U - This means this is a "User" account, i.e. an ordinary
90 user.
91 · N - This means the account has no password (the passwords in
93 the fields LANMAN Password Hash and NT Password Hash are
94 ignored). Note that this will only allow users to log on with
95 no password if the
96 null passwords parameter is set in the smb.conf(5) config
97 file.
98 · D - This means the account is disabled and no SMB/CIFS logins
100 will be allowed for this user.
101 · X - This means the password does not expire.
103 · W - This means this account is a "Workstation Trust" account.
105 This kind of account is used in the Samba PDC code stream to
106 allow Windows NT Workstations and Servers to join a Domain
107 hosted by a Samba PDC.
108 Other flags may be added as the code is extended in future. The
110 rest of this field space is filled in with spaces. For further
111 information regarding the flags that are supported please refer
112 to the man page for the pdbedit command.
113 Last Change Time
115 This field consists of the time the account was last modified. It
116 consists of the characters 'LCT-' (standing for "Last Change Time")
117 followed by a numeric encoding of the UNIX time in seconds since the
118 epoch (1970) that the last change was made.
119 All other colon separated fields are ignored at this time.
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123 This man page is correct for version 3.0 of the Samba suite.
124
126 smbpasswd(8), Samba(7), and the Internet RFC1321 for details on the MD4
127 algorithm.
128
130 The original Samba software and related utilities were created by
131 Andrew Tridgell. Samba is now developed by the Samba Team as an Open
132 Source project similar to the way the Linux kernel is developed.
133 The original Samba man pages were written by Karl Auer. The man page
135 sources were converted to YODL format (another excellent piece of Open
136 Source software, available at ftp://ftp.icce.rug.nl/pub/unix/) and
137 updated for the Samba 2.0 release by Jeremy Allison. The conversion to
138 DocBook for Samba 2.2 was done by Gerald Carter. The conversion to Doc‐
139 Book XML 4.2 for Samba 3.0 was done by Alexander Bokovoy.
140 SMBPASSWD(5)