OSX v10.7 Hash

What is OSX v10.7?

The OS X v10.7 password hash format, introduced by Apple in 2011 as part of its transition from legacy Unix-style cryptographic schemes, represents a proprietary evolution of the Unix-style crypt(3) hashing mechanism tailored for macOS. Structurally, it employs a modified version of the **DES-based crypt(3) algorithm** with a fixed-length output of 16 bytes (128 bits), encoded as a 22-character string in the format `OSX$`. The salt is a 16-character hexadecimal string (8 bytes) prepended to the password before hashing, followed by a 4-character iteration count (default: `1000`) and a 12-character hashed result. Unlike traditional Unix hashes, this format incorporates a **checksum byte** (the 22nd character) to detect corruption, and it supports **key stretching** via the iteration count, though this was later deemed insufficient for modern security standards. Primarily, this format was designed for backward compatibility with legacy macOS systems while introducing minor hardening against trivial brute-force attacks, though its core reliance on DES rendered it vulnerable from inception.

The OSX v10.7 hash format is fundamentally vulnerable to cracking due to its reliance on **DES-based cryptography**, which is inherently weak against contemporary computational power. The algorithm’s fixed iteration count (1000) is trivial to bypass with modern GPU-accelerated cracking tools like **Hashcat**, as it lacks adaptive key stretching or a salted iteration mechanism. Additionally, the absence of a **cryptographic salt** in the traditional sense (the 8-byte salt is deterministic per username) enables **rainbow table attacks** when combined with precomputed hashes. The 56-bit DES core is also susceptible to **brute-force attacks** due to its small key space, with modern GPUs capable of cracking such hashes in seconds. Furthermore, the checksum byte, while useful for integrity verification, does not mitigate against hash collisions or reverse-engineering of the underlying plaintext. Optimizations like **OpenCL-based cracking** further exacerbate the vulnerability, as the hash’s linear complexity allows for massive parallelization, rendering it obsolete by modern standards.

Identifying OSX v10.7 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 OSX v10.7, security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack OSX v10.7

If you need to recover the plaintext password for a OSX v10.7 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.