md4($salt.$pass) Hash

What is md4($salt.$pass)?

MD4 was designed in 1990 by Ronald L. Rivest as part of the MD family of cryptographic hash functions, serving as a precursor to MD5 and SHA-1. Structurally, MD4 processes input data in 512-bit blocks through a compression function that iteratively applies three distinct rounds of bitwise operations (left rotations, AND/XOR/OR operations, and modular additions) to maintain a 128-bit chaining value. The format `md4($salt.$pass)` concatenates a salt (a unique, randomly generated value) with the user-provided password before hashing, a technique intended to thwart precomputation attacks. This construction was primarily deployed in early password storage schemes, where simplicity and computational efficiency were prioritized over security, though it was never officially standardized for cryptographic purposes due to its known vulnerabilities.

The `md4($salt.$pass)` format is critically vulnerable due to MD4’s inherent design flaws and practical attack vectors. MD4 suffers from severe collision weaknesses—distinct inputs can produce identical hashes with non-negligible probability—exploitable via brute-force or precomputed rainbow tables, especially when salts are weak or reused. Modern hardware acceleration (GPU/FPGA clusters) enables massive parallel cracking of MD4 hashes at rates exceeding 100+ billion hashes per second, rendering it trivially breakable for short passwords. Additionally, MD4’s fixed-round structure lacks avalanche effects, allowing attackers to exploit bit-level patterns in plaintext-to-hash transitions. The lack of iterative hashing (unlike bcrypt or Argon2) means no adaptive computational cost, and its 128-bit output is insufficient against quantum-resistant attacks or modern brute-force strategies. The format’s obsolescence is further cemented by NIST’s deprecation of MD4 in favor of SHA-2/3, rendering it unsuitable for any security-critical application.

Identifying md4($salt.$pass) 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 md4($salt.$pass), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack md4($salt.$pass)

If you need to recover the plaintext password for a md4($salt.$pass) 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.