Not to be confused with the "passwd" key used in the Name Service Switch, which can use /etc/passwd as a source.
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passwd
Original author(s)
AT&T Bell Laboratories
Developer(s)
Various open-source and commercial developers
Operating system
Unix, Unix-like, Plan 9, Inferno
Platform
Cross-platform
Type
Command
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is run through a key derivation function to create a hashed version of the new password, which is saved. Only the hashed version is stored; the entered password is not saved for security reasons.
When the user logs on, the password entered by the user during the log on process is run through the same key derivation function and the resulting hashed version is compared with the saved version. If the hashes are identical, the entered password is considered to be correct, and the user is authenticated. In theory, it is possible for two different passwords to produce the same hash. However, cryptographic hash functions are designed in such a way that finding any password that produces the same hash is very difficult and practically infeasible, so if the produced hash matches the stored one, the user can be authenticated.
The passwd command may be used to change passwords for local accounts, and on most systems, can also be used to change passwords managed in a distributed authentication mechanism such as NIS, Kerberos, or LDAP.
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is...
mechanisms. These sources include local operating system files (such as /etc/passwd, /etc/group, and /etc/hosts), the Domain Name System (DNS), the Network...
the root directory, and then include the Unix password file /etc/passwd. Unix /etc/passwd is a common file used to demonstrate directory traversal, as it...
in a number of important text files called databases. This includes the passwd and group databases which store user information – hence getent is a common...
must have GID 0. This numeric value is used to refer to groups in the /etc/passwd and /etc/group files or their equivalents. Shadow password files and Network...
The gecos field, or GECOS field is a field in each record in the /etc/passwd file on Unix and similar operating systems. On UNIX, it is the 5th of 7 fields...
the shell interactively. chsh is a setuid program that modifies the /etc/passwd file, and only allows ordinary users to modify their own login shells. The...
of user and group files that can be modified by the vipw utility. “/etc/passwd“: User account information. “/etc/shadow“: Secure user account information...
UNIX environment, the list of users for identification is placed in /etc/passwd and secret authentication hashes in /etc/shadow. NIS adds another "global"...
that order. The users are sorted by default according to the order in /etc/passwd However, it can also be used to modify the records kept in /var/log/lastlog...
reject accessing the file "/etc/passwd", a cracker might pass another variant of this file name, like "/etc/./passwd". Canonicalization libraries can...
user, is typically stored in the user's profile, for example in the local passwd file or in a distributed configuration system such as NIS or LDAP; however...
Comprehensive Operating System (GCOS) gecos field, an entry in the /etc/passwd file containing personal data about the user on Unix operating systems This...
/vulnerable.php?language=../../../../../etc/passwd%00 - allows an attacker to read the contents of the /etc/passwd file on a Unix-like system through a directory...
and many others. User utilities – environment management tools such as passwd, kill, and others. Document formatting – Unix systems were used from the...
control over the machine. Hypervisor Jailbreaking (iOS) nobody (username) passwd Power user Privilege escalation Rooting (Android OS) Rootkit sudo Wheel...
no longer maintained ConsoleKit. BSD Authentication Name Service Switch passwd Pluggable authentication module "Configuring Login Manager". Solaris Common...
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