PBKDF2-SHA1(Generic) Hash

What is PBKDF2-SHA1(Generic)?

PBKDF2-SHA1(Generic) is a key derivation function (KDF) standardized in RFC 2898, designed to mitigate the limitations of direct cryptographic hashing for password storage by incorporating iterative hashing, salt, and optional stretching parameters. Its structure consists of a core iterative process where the input password is hashed repeatedly with a pseudorandom function (typically SHA-1 in this case) using a salt and iteration count to produce a derived key. The "Generic" variant refers to its flexibility in accommodating different underlying hash functions (though SHA-1 is the most common implementation), enabling it to balance security with computational feasibility. Primarily used in authentication systems (e.g., SSH, TLS, and early web frameworks), PBKDF2-SHA1 was intended to defend against brute-force attacks by increasing computational overhead, though its reliance on SHA-1—now considered cryptographically broken due to collision vulnerabilities—undermines its long-term viability. The format’s strength lies in its adaptability to security parameters (e.g., iteration counts) and explicit salt integration, though these features were often misconfigured in practice, leaving systems vulnerable to optimized attacks.

The vulnerability of PBKDF2-SHA1 stems from its reliance on SHA-1’s inherent weaknesses, including its susceptibility to collision attacks (e.g., SHA-1 hashing to 512-bit preimages in ~2^69 operations) and its poor resistance to length-extension attacks when combined with HMAC. Additionally, the algorithm’s iterative nature, while intended to slow down brute-force attempts, is easily optimized using parallel hardware like GPUs or FPGAs, particularly when iteration counts are insufficient (commonly set too low, e.g., <10,000 iterations). Poor salt practices—such as non-uniqueness or omission—eliminate the entropy needed to prevent rainbow table attacks, while SHA-1’s 160-bit output space enables practical dictionary attacks via precomputed hashes. Furthermore, modern advancements in quantum-resistant cryptography and the availability of high-throughput cracking tools (e.g., Hashcat’s GPU-accelerated PBKDF2-SHA1 modes) render PBKDF2-SHA1 impractical for contemporary security standards, as its computational cost can be neutralized with optimized hardware.

Identifying PBKDF2-SHA1(Generic) 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 PBKDF2-SHA1(Generic), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack PBKDF2-SHA1(Generic)

If you need to recover the plaintext password for a PBKDF2-SHA1(Generic) 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.