>>>>> "Sandu" == Sandu Mihai <mikeat_private> writes: Sandu> When you use a certain mysql configuration it is possible to create Sandu> files on the system as root with rw-rw-rw. Sandu> Many MySQL users have included user root from localhost without password Sandu> in their config. Sandu> So. If on such a system you issue : Sandu> mysql -u root test Sandu> you not only will have access to the database but you'll be able to Sandu> create a file on the system with the root Sandu> ownership and rw-rw-rw useing the SELECT .. INTO OUTFILE statement. Sandu> The file you wish to create must NOT EXIST. Otherwise mysql will give Sandu> you a "file already exists" error. Sandu> To be more precise. MySQL will create the file specified as OUTFILE Sandu> with rw-rw-rw and with the current Sandu> user as owner. Sandu> The exploit is as follows: Sandu> mysql -u root test Sandu> CREATE TABLE ll ( a CHAR(10) ); Sandu> INSERT INTO aa (a) VALUES ("+ +"); Sandu> SELECT * FROM aa INTO OUTFILE "/root/.rhosts"; Sandu> The above exploit works for sites with rexec,rsh enabled (ssh is too Sandu> smart and won't let you in Sandu> if you have .rhosts 666, the same for authorized_keys) Sandu> Well . I've tryied to be tricky by setting umask to 077 in the hope Sandu> that I can trick MySQL in Sandu> makeing the file 600 , childish try, I know but... who knows ? Sandu> If someone could fool MySQL into makeing the file 600 then this is Sandu> quite a serious threat.. The file is always created with 0666, by the following code: sql_class.cc:167: if ((file=my_create(path, 0666, O_WRONLY, MYF(MY_WME))) < 0) Normally one should never run mysqld as root and one should always set a password for the MySQL root user. We shall add a security section to the manual! Yours, Monty
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 13:47:23 PDT