MSSQL(2005) Hash

What is MSSQL(2005)?

The **MSSQL(2005)** hash format, originally introduced by Microsoft in SQL Server 2005, is a proprietary cryptographic hash designed to store and verify user passwords within its relational database engine. Structurally, it combines a **SHA-1-based** hash with a **custom prefix** (typically `0x01` or `0x02` for different versions) and an **unencrypted salt** embedded within the hash itself. The format stores passwords as a **64-character hexadecimal string** (32 bytes) derived from a two-step process: first, the plaintext password is hashed with SHA-1, then concatenated with a **fixed-length salt** (often derived from the username or a static value), and finally rehashed. This design was intended to mitigate trivial offline attacks by obfuscating the raw password, but it lacks modern cryptographic best practices such as per-password salting or key stretching. The primary use-case was password storage in SQL Server 2005–2008, where compatibility with legacy systems outweighed security concerns.

The **MSSQL(2005)** format is highly vulnerable to cracking due to its **predictable salt structure**, **SHA-1’s susceptibility to collision attacks**, and **optimized offline brute-forcing**. The embedded salt (often the username or a static value) renders rainbow table precomputation ineffective only if the salt is unknown, but its deterministic nature allows attackers to precompute hashes for common usernames. Additionally, SHA-1’s **56-bit effective security** makes it feasible to crack short passwords via **GPU-accelerated rainbow tables** (e.g., using tools like **Hashcat’s `mssql_2005` mode**) in hours or days. The absence of **key stretching** (e.g., PBKDF2, bcrypt) means that modern hardware can evaluate millions of hashes per second, while **collision resistance** is further compromised by SHA-1’s known weaknesses, enabling **birthday attack** exploits. Finally, the **lack of salting per password** (only per-user) reduces entropy, and the **fixed-length output** enables **dictionary attacks** to be parallelized efficiently across GPUs.

Identifying MSSQL(2005) 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 MSSQL(2005), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack MSSQL(2005)

If you need to recover the plaintext password for a MSSQL(2005) 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.