Mysql Hacktricks Verified !!exclusive!! May 2026

Based on the MySQL HackTricks verified methodology, one of the most "interesting" (and often overlooked) features is the ability to read and write files to the underlying operating system using standard SQL queries, which effectively turns the database into a file system browser or a reverse shell generator.

Here are the two most interesting facets of this feature:

2.1. UDF (User Defined Function) Exploitation

Verified technique: If the secure_file_priv variable is empty (or points to a writable directory) and the MySQL service runs as root or a high‑privileged user, an attacker can: mysql hacktricks verified

  1. Compile a shared library (e.g., lib_mysqludf_sys.so) containing sys_exec() and sys_eval().
  2. Upload it via SELECT INTO DUMPFILE.
  3. Create UDFs to execute arbitrary OS commands.

This is a classic privilege escalation path, verified to work on older MySQL versions (5.x, early 8.x) and misconfigured production servers.

7. MySQL Sandbox Escape (for MySQL hosted services like phpMyAdmin)

If you only have SELECT/INSERT privileges, try: Based on the MySQL HackTricks verified methodology, one

5.1 Bypassing secure_file_priv via Race Conditions (Linux)

In some older MySQL/MariaDB versions, a race condition exists between checking secure_file_priv and opening the file. Not reliable on patched systems, but for CTFs, try:

  • Create a symlink from a permitted directory to a web root.
  • Use SELECT ... INTO DUMPFILE and quickly replace the target file during the 1ms window.

1. Reading Local Files (Data Exfiltration)

If the MySQL user has the FILE privilege and the secure_file_priv configuration allows it (or is empty), you can read arbitrary files from the server's disk using a standard SELECT statement. Compile a shared library (e

The "HackTrick": You don't need to load data into a table; you can load it directly into a result set using LOAD_FILE().

SELECT LOAD_FILE('/etc/passwd');

Why it's interesting:

  • It allows you to read configuration files, private keys, or even the MySQL history file (~/.mysql_history) which might contain passwords.
  • Bypass: If LOAD_FILE is blocked or you want to see if a file exists without reading it, HackTricks suggests using a side-channel approach: creating a table with an IMPORT statement or simply observing error messages.

1. Union-Based SQL Injection

  • Payload: UNION SELECT NULL,NULL,NULL -- -
  • Description: This payload is used to extract data from the database by injecting malicious SQL code.

Example:

http://example.com/vulnerable-page?id=1 UNION SELECT NULL,NULL,NULL -- -