You need to make sure your mysql authentication scheme has been cleaned up
MySQL 5.0 Certification Study Guide says on Page 498 Paragraph 6 in its bulletpoints brings out how to cleanup the authentication process:
On Unix, MySQL comes with a mysql_secure_installation script that can
perform several helpful security-related operations on your
installation. The script has the following capabilities:
- Set a password for the root accounts
- Remove any remotely accessible root accounts.
- Remove the anonymous user accounts. This improves security because
it prevents the possibility of anyone connecting to the MySQL server
as root from a remote host. The results is that anyone who wants to
connect as root must first be able to log in on the server host, which
provides an additional barrier against attack.
- Remove the test database (If you remove the anonymous accounts, you
might also want to remove the test database to which they have
A remotely accessible account is an account whose host is
% which allows anyone and his grandmother. To find those accounts, run this query:
SELECT user,host FROM mysql.user WHERE host='%';
You should also be cognizant of how MySQL user authentication occurs.
According to MySQL 5.0 Certification Study Guide pages 486,487, the following describes mysql's authentication algorithm:
There are two stages of client access control:
In the first stage, a client attempts to connect and the server either
accepts or rejects the connection. For the attempt to succeed, some
entry in the user table must match the host from which the client
connects, the username, and the password.
In the second stage (which occurs only if a client has already
connected successfully), the server checks every query it receives from
the client to see whether the client has sufficient privileges to
The server matches a client against entries in the grant tables based
on the host from which the client connects and the user the client
provides. However, it's possible for more than one record to match:
Host values in grant tables may be specified as patterns contains
wildcard values. If a grant table contains entris from
%, all of them
match a client who connects from
Patterns are not allowed for the User values in grant table entries,
but a username may be given as an empty string to specify an anonymous
user. The empty string matches any username and thus effectively acts
as a wildcard.
When the Host and the User values in more than one user table record
match a client, the server must decide which one to use. It does this
by sorting records with the most specific Host and User column values
first, and choosing the matching record that occurs first in the
sorted list, Sorting take place as follows:
In the Host Column, literal values such as
myhost.example.com sort ahead of values such as
that have pattern characters in them. Pattern values are sorted
according to how specific they are. For example,
more specific than
%.com, which is more specific than
In the User column, non-blank usernames sort ahead of blank usernames.
That is, non-anonymous users sort ahead of anonymous users.
The server performs this sorting when it starts. It reads the grant
tables into memory, sorts them, and uses the in-memory copies for
If you have any users that must have remote access, change the host of each user that has
% into the public IP you will be connecting from.
For example, if the user
myuser must connect from 220.127.116.11, replace the host like this
UPDATE mysql.user SET host='18.104.22.168' WHERE user='myuser' AND host='%';
You should also be checking for the presence of any test databases. The presence of test databases. Any database named
test or whose first five(5) characters are
test_ need to be renamed immediately !!! I wrote an earlier post on how and why.