Re: MySQL user can be changed to root

I can confirm this privilege escalation in mysql-server 3.23.49-8.2
(debian/stable on linux/i386). Any mysql user with file privileges can trick
the mysql server into running as root on restart of the mysql subsystem.

Note that mysql prevents you from reading non-world-readable files outside
the mysql data directory, or overwriting existing files. You can create new
files as root, though.

mysql> load data infile '/etc/shadow' into table readtext;
ERROR 1085: The file '/etc/shadow' must be in the database directory or be
readable by all
mysql> select * into outfile '/etc/somenewfile' from hack;
Query OK, 2 rows affected (0.00 sec)

-rw-rw-rw- 1 root root 19 Mar 10 17:22 /etc/somenewfile

Not a rootshell, yet, but lots of new avenues from here.

:*CU#



bugsman@libero.it wrote:

> mysql>SELECT * INTO OUTFILE '/path/to/mysql/datadir/my.cnf' FROM hack

> Now, when the mysql server will be restarted, the user option in our
> datadir my.cnf will override the one in /etc/my.cnf and mysql server will
> run as root



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Re: MySQL user can be changed to root

Hi!

Both to bugtraq and mysql list:

This issue has been adressed in 3.23.56 (release build is started
today), and some steps were taken to alleviate the threat.

In particular, MySQL will no longer read config files that are
world-writeable (and SELECT ... OUTFILE always creates world-writeable
files). Also, unlike other options, for --user option the first one will
have the precedence. So if --user is set in /etc/my.cnf (as it is
recommended in the manual), datadir/my.cnf will not be able to override
it.

Fixing this issue in more robust way would mean introducing too big and
incompatible changes into stable version, thus breaking lots of
installations. It is to be done in 4.1.

Regards,
Sergei

On Mar 10, Guido A.J. Stevens wrote:
>
> I can confirm this privilege escalation in mysql-server 3.23.49-8.2
> (debian/stable on linux/i386). Any mysql user with file privileges can
> trick the mysql server into running as root on restart of the mysql
> subsystem.
>
> bugsman@libero.it wrote:
>
> > mysql>SELECT * INTO OUTFILE '/path/to/mysql/datadir/my.cnf' FROM hack
>
> > Now, when the mysql server will be restarted, the user option in our
> > datadir my.cnf will override the one in /etc/my.cnf and mysql server will
> > run as root

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__ ___ ___ ____ __
/ |/ /_ __/ __/ __ \/ / Sergei Golubchik
/ /|_/ / // /\ \/ /_/ / /__ MySQL AB, http://www.mysql.com/
/_/ /_/\_, /___/\___\_\___/ Osnabrueck, Germany
<___/

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