EPiServer 6.x ≥ v4 Hash

What is EPiServer 6.x ≥ v4?

The **EPiServer 6.x ≥ v4** password hash format is a proprietary cryptographic scheme introduced by EPiServer (now part of SDL) to secure user credentials in their CMS platform, primarily targeting versions 4.x and above of their legacy systems. This format is a variant of **MD5-based hashing with a custom prefix**, where the stored hash follows the structure `EPiServer6x≥v4$$`. The salt is a 16-byte random value prepended to the plaintext password before applying a single MD5 iteration, producing a 128-bit (32-character hexadecimal) hash. Unlike modern standards like bcrypt or Argon2, this scheme lacks iterative hashing (e.g., no built-in work factor) and relies solely on MD5’s native speed, making it unsuitable for contemporary security requirements. Its primary use-case was internal authentication within EPiServer’s CMS, where performance was prioritized over resistance to brute-force attacks, reflecting the security practices of mid-2000s web applications.

The vulnerability of this format stems from its **lack of salt iteration, weak collision resistance, and susceptibility to GPU/ASIC optimization**. Since the salt is only applied once before a single MD5 pass, the hash function operates at a constant time complexity of *O(1)*, enabling attackers to leverage high-performance hardware (e.g., GPUs or FPGA-based crackers) to brute-force credentials at rates exceeding **millions of hashes per second**. Additionally, MD5’s inherent collision susceptibility—exacerbated by the absence of a work factor—allows for precomputed rainbow tables or dictionary attacks on unsalted or weakly salted passwords. The format’s reliance on a fixed-length salt (16 bytes) also risks salt reuse in edge cases, further reducing entropy. Finally, the absence of key stretching or post-processing makes the scheme vulnerable to **cryptanalysis via brute-force or hybrid attacks**, rendering it obsolete by modern standards.

Identifying EPiServer 6.x ≥ v4 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 EPiServer 6.x ≥ v4, security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack EPiServer 6.x ≥ v4

If you need to recover the plaintext password for a EPiServer 6.x ≥ v4 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.