MySQL5.x Hash

What is MySQL5.x?

The **MySQL5.x** password hash format, introduced in MySQL versions 5.0.1 through 5.7.x, is a legacy cryptographic scheme derived from the **UNIX crypt(3)** algorithm with modifications tailored for MySQL’s authentication system. Structurally, it encodes passwords as a 16-character hexadecimal string prefixed with `$MySQL5.x$`, followed by a salt (typically 22 characters long, combining a random string and the username) and the hashed output. Unlike modern hashes, it employs a **crypt-style** approach using a **DES-based** (or later, **Blowfish-based**) cipher with a fixed iteration count (originally 1000 for DES, later adjusted to 4096 for Blowfish in MySQL 5.7). This format was designed for backward compatibility with older UNIX password systems but lacked cryptographic best practices, such as adaptive work factors or salting strategies. Its primary use-case was secure storage of plaintext passwords in MySQL databases, though it was deprecated in favor of stronger mechanisms like **MySQL Native Password (MySQL4.1)** or **SHA-256** in later versions.

The **MySQL5.x** hash format is highly vulnerable to cracking due to its **predictable iteration count, lack of adaptive salting, and susceptibility to brute-force attacks**. Early versions (DES-based) suffered from **fixed-round iterations**, allowing attackers to leverage **GPU-accelerated rainbow tables** or **dictionary attacks** with optimized tools like **Hashcat** or **John the Ripper**. The absence of a **dynamic salt** (e.g., per-user or per-password) reduces entropy, enabling **precomputed attacks** on common passwords. Later versions (Blowfish-based) improved slightly by increasing iterations, but the **static salt derivation** (username concatenation) remains exploitable via **credential stuffing** or **offline brute-force**. Additionally, the **hexadecimal output format** facilitates **collision attacks** and **hash collision exploits**, while the **lack of timing attacks mitigations** (e.g., constant-time comparison) allows for **side-channel analysis**. Modern hardware (GPUs/ASICs) can crack these hashes in **sub-second to minutes**, rendering them unsuitable for contemporary security standards.

Identifying MySQL5.x Hashes

Identifying a hash blindly is often difficult because multiple algorithms can output strings of the exact same length. For example, a standard 32-character hexadecimal string could be MD5, NTLM, MD4, or LM. To definitively identify MySQL5.x, security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack MySQL5.x

If you need to recover the plaintext password for a MySQL5.x hash during a penetration test or forensics investigation, you must supply the correct module ID to your cracking software. Use the exact commands provided at the top of this page to target the hash successfully.