AIX(ssha256) Hash

What is AIX(ssha256)?

The **AIX(ssha256)** hash format is a variant of the **SSHA (Salted SHA-256)** algorithm, originally designed as an extension to the classic Unix password hashing scheme to mitigate rainbow table attacks. Structurally, it follows a modified **ETM+ (Extended Twofish-Mix) format**, where the password hash is stored in a binary blob containing a 32-byte salt, a 32-byte iteration count (typically encoded as a big-endian 32-bit value repeated eight times), and the final 32-byte SHA-256 hash of the password concatenated with the salt and iteration count. This format was introduced in **AIX 5L (IBM’s Unix variant)** as part of its enhanced password security framework, aiming to balance computational overhead with resistance to brute-force attacks by enforcing high iteration counts (often 10,000 or more). Unlike traditional Unix hashes (e.g., MD5-based), SSHA256 leverages SHA-256’s collision resistance and cryptographic strength, though its security ultimately depends on the iteration count and proper salt handling—unlike pure SHA-256, it avoids storing plain salts in plaintext by embedding them within the hash structure.

The **AIX(ssha256)** format is vulnerable to cracking primarily due to **suboptimal iteration enforcement and GPU/ASIC optimizations**. Early implementations of SSHA256 in AIX often used fixed or predictably low iteration counts (e.g., 10,000), which, while sufficient in the mid-2000s, became trivial to bypass with modern GPU-accelerated cracking tools like **Hashcat** or **John the Ripper with CUDA/OpenCL support**. The lack of a **dynamic salt** (the salt is fixed per user but not per hash iteration) allows attackers to precompute or parallelize attacks efficiently. Additionally, the **ETM+ format’s binary structure** can be parsed and cracked in bulk using optimized algorithms, as the salt and iterations are embedded rather than obfuscated. Unlike modern key-stretching schemes (e.g., Argon2 or bcrypt), SSHA256 lacks **memory-hard properties**, making it susceptible to **GPU/ASIC-based brute-force** once iteration counts are known or guessed. Finally, the **absence of a built-in key derivation function (KDF) with adaptive work factors** means that even if iterations are high, attackers can exploit **parallelization** and **optimized SHA-256 implementations** to reduce cracking time exponentially.

Identifying AIX(ssha256) 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 AIX(ssha256), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack AIX(ssha256)

If you need to recover the plaintext password for a AIX(ssha256) 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.