MSSQL(2000) Hash

What is MSSQL(2000)?

The **MSSQL(2000) hash format** originated as a proprietary password hashing scheme introduced by Microsoft SQL Server 2000 to secure user credentials stored in its authentication database. Structurally, it combines a truncated MD4 hash (16 bytes) with a 4-byte salt appended at the end, resulting in a 20-byte binary representation. The algorithm processes the input password by first applying MD4 to generate a 128-bit digest, then truncating it to 128 bits (16 bytes) before concatenating a 4-byte salt derived from the user’s SID or a fixed value. This format was primarily designed for internal SQL Server authentication, where passwords were stored in a binary format readable by the server’s native functions, enabling efficient comparison without full decryption. While it improved upon earlier SQL Server hashing methods (such as the plaintext or weak hashes used in earlier versions), it retained critical design flaws that rendered it susceptible to cryptanalysis.

The **MSSQL(2000) hash is vulnerable to cracking primarily due to its reliance on MD4’s inherent weaknesses, lack of salting robustness, and optimizable structure**. MD4’s collision resistance is well-documented as insufficient, allowing attackers to exploit rainbow tables or brute-force attacks with optimized tools like Hashcat or John the Ripper, which leverage GPU/CPU parallelism to crack truncated MD4 hashes in minutes. The 4-byte salt, though present, is often predictable or reused across users, reducing entropy and enabling precomputed attacks. Additionally, the fixed-length output (16-byte digest + 4-byte salt) allows for efficient offline cracking via dictionary attacks or hybrid methods, as the hash space remains manageable despite the truncation. Modern hardware acceleration further exacerbates the vulnerability, as GPUs can evaluate millions of hashes per second, rendering the scheme unsuitable for contemporary security standards.

Identifying MSSQL(2000) 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(2000), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack MSSQL(2000)

If you need to recover the plaintext password for a MSSQL(2000) 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.