MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
MySQL users should use the following guidelines to keep passwords secure.
When you run a client program to connect to the MySQL server, it is inadvisable to specify your password in a way that exposes it to discovery by other users. The methods you can use to specify your password when you run client programs are listed here, along with an assessment of the risks of each method. In short, the safest methods are to have the client program prompt for the password or to specify the password in a properly protected option file.
Use the mysql_config_editor utility,
which enables you to store authentication credentials in an
encrypted login path file named
.mylogin.cnf
. The file can be read
later by MySQL client programs to obtain authentication
credentials for connecting to MySQL Server. See
Section 4.6.6, “mysql_config_editor — MySQL Configuration Utility”.
Use a
--password=
or password
-p
option on the command line. For example:
password
shell> mysql -u francis -pfrank db_name
This is convenient but insecure. On some systems, your password becomes visible to system status programs such as ps that may be invoked by other users to display command lines. MySQL clients typically overwrite the command-line password argument with zeros during their initialization sequence. However, there is still a brief interval during which the value is visible. Also, on some systems this overwriting strategy is ineffective and the password remains visible to ps. (SystemV Unix systems and perhaps others are subject to this problem.)
If your operating environment is set up to display your current command in the title bar of your terminal window, the password remains visible as long as the command is running, even if the command has scrolled out of view in the window content area.
Use the --password
or
-p
option on the command line with no
password value specified. In this case, the client program
solicits the password interactively:
shell> mysql -u francis -p db_name
Enter password: ********
The *
characters indicate where you enter
your password. The password is not displayed as you enter
it.
It is more secure to enter your password this way than to specify it on the command line because it is not visible to other users. However, this method of entering a password is suitable only for programs that you run interactively. If you want to invoke a client from a script that runs noninteractively, there is no opportunity to enter the password from the keyboard. On some systems, you may even find that the first line of your script is read and interpreted (incorrectly) as your password.
Store your password in an option file. For example, on Unix,
you can list your password in the
[client]
section of the
.my.cnf
file in your home directory:
[client]
password=password
To keep the password safe, the file should not be accessible
to anyone but yourself. To ensure this, set the file access
mode to 400
or 600
.
For example:
shell> chmod 600 .my.cnf
To name from the command line a specific option file
containing the password, use the
--defaults-file=
option, where file_name
file_name
is the full
path name to the file. For example:
shell> mysql --defaults-file=/home/francis/mysql-opts
Section 4.2.2.2, “Using Option Files”, discusses option files in more detail.
Store your password in the MYSQL_PWD
environment variable. See
Section 4.9, “Environment Variables”.
This method of specifying your MySQL password must be
considered extremely insecure and
should not be used. Some versions of ps
include an option to display the environment of running
processes. On some systems, if you set
MYSQL_PWD
, your password is exposed to
any other user who runs ps. Even on
systems without such a version of ps, it
is unwise to assume that there are no other methods by which
users can examine process environments.
On Unix, the mysql client writes a record of
executed statements to a history file (see
Section 4.5.1.3, “mysql Client Logging”). By default, this file is named
.mysql_history
and is created in your home
directory. Passwords can be written as plain text in SQL
statements such as CREATE USER
,
GRANT
, and
SET PASSWORD
, so if you use these
statements, they are logged in the history file. To keep this
file safe, use a restrictive access mode, the same way as
described earlier for the .my.cnf
file.
If your command interpreter is configured to maintain a history,
any file in which the commands are saved contains MySQL
passwords entered on the command line. For example,
bash uses
~/.bash_history
. Any such file should have
a restrictive access mode.