Because MD5 is a , reversing the output to the input password is mathematically infeasible.
# Save hash in file (cisco.hash) $1$mERr$hP5YqQk5Q6Y9Z9Xj5x5Zz/ decrypt cisco password 5
2026-04-14 Subject: Analysis of Cisco Type 5 password hashing and recovery limitations Because MD5 is a , reversing the output
| Type | Algorithm | Reversible? | Security | |------|-----------|-------------|----------| | Type 0 | Plaintext | Yes | None | | Type 5 | MD5-based hash | No | Moderate | | Type 7 | Vigenère cipher (obfuscation) | Yes (trivially) | Very weak | | Type 8 | PBKDF2-SHA256 | No | Strong | | Type 9 | SCRYPT | No | Strongest | Because MD5 is a
Utilities like the netutils library in Python can be used to programmatically compare a cleartext guess against a Type 5 hash. :
