MySQL4.1 Hash

What is MySQL4.1?

The **MySQL4.1** password hash format emerged as part of MySQL’s early authentication mechanisms, designed to store user credentials in a way that could be verified against plaintext passwords during login. Originating from the legacy **UNIX crypt(3)** function with modifications, it encodes passwords using a **DES-based cipher** (specifically, a truncated 16-round DES-EDE3 with a fixed key derivation scheme) and stores the result as a 16-character hexadecimal string. Unlike modern formats, it lacks a salt by default, relying instead on a **static salt derived from the username** (via `md5(username) % 256`), which was intended to mitigate trivial rainbow table attacks. This format was primarily used in MySQL versions 4.1 and earlier, where security was secondary to compatibility with existing systems, and was later deprecated in favor of stronger algorithms like `mysql_native_password` (which uses `scramble()` with salts) or `caching_sha2_password`.

The **MySQL4.1** hash is highly vulnerable to cracking due to its **predictable salt derivation**, **weak cryptographic primitives**, and **optimized attack surfaces**. The reliance on **DES-EDE3** (a 192-bit key cipher) is rendered obsolete by modern computational power, as brute-force attacks can be executed efficiently using **GPU-accelerated tools** like Hashcat or John the Ripper, which leverage **parallelized DES cracking** (e.g., via the `des-whirlpool` or `des-xcipher` attack modes). The absence of a **per-password salt** means attackers can precompute **rainbow tables** for all possible salted hashes, drastically reducing cracking time. Additionally, the **fixed-length output (16 bytes)** and **deterministic nature** of the hash function enable **collision attacks** and **dictionary-based recovery** when combined with weak passwords. Finally, the **lack of iteration counts or key stretching** makes it trivial to offload computations to specialized hardware, further accelerating decryption. These flaws render MySQL4.1 **catastrophically insecure** by contemporary standards.

Identifying MySQL4.1 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 MySQL4.1, security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack MySQL4.1

If you need to recover the plaintext password for a MySQL4.1 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.