This tool is part of the Samba(7) suite.
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.
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 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:
name ” This is the user name. It must be a name that already exists in the standard UNIX passwd file.
uid ” 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.
Lanman Password Hash ” 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 disabled and the user will not be able to log onto the Samba server.
NT Password Hash ” 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.
Account Flags ” This section contains flags that describe the attributes of the users account. In the Samba 2.2 release this field is bracketed by '[' and ']' characters and is always 13 characters in length (including the '[' and ']' characters). The contents of this field may be any of the following characters:
Last Change Time ” This field consists of the time the account was last modified. It consists of the characters 'LCT-' (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.
smbpasswd(8), Samba(7), and the Internet RFC1321 for details on the MD4 algorithm.