When you configure enable secret mypassword , Cisco IOS does not encrypt the password to be decrypted later. Instead, it runs "mypassword" through a modified MD5 hashing function and stores the resulting fixed-length string. The Anatomy of a Type 5 Hash
Utilizes the Secure Hash Algorithm 256-bit standard with a salt. It offers much higher computational resistance than MD5.
R1(config)# enable secret NewStrongPassword R1(config)# do show running-config | include enable secret enable secret 5 $1$8ZxQ$iLk3mN7jH5...
key on a console connection) and changing the configuration register to ignore the startup configuration Type 5 vs. Type 7 Comparison Cisco Router Password Decryption - SolarWinds cisco secret 5 password decrypt
The most common and effective tools for this task are and Hashcat .
Decryption requires a key to return a ciphertext to plaintext. MD5 is a , designed to be a one-way mathematical operation. To "recover" a Type 5 password, an attacker must: Guess a possible plaintext password. Apply the same MD5 algorithm and salt.
| Cisco Type | Algorithm | Reversible? | Recommended | |------------|-----------|-------------|--------------| | Type 5 | MD5 + salt | ❌ (crackable) | No | | Type 8 | PBKDF2-SHA256 | ❌ | ✅ Yes | | Type 9 | SCRYPT | ❌ | ✅ Yes (best) | When you configure enable secret mypassword , Cisco
While MD5 itself has suffered from severe cryptographic collisions since the early 2000s, Cisco’s Type 5 implementation remains moderately resilient due to the inclusion of unique salts and iterated stretching. However, it is no longer considered safe by modern standards. Performance and Speed
For security professionals who need to build cracking into a larger script or work in restricted environments, Python offers excellent libraries.
Utilizes a memory-hard algorithm explicitly designed to thwart GPU-accelerated cracking rigs. This is currently the most secure local storage option on supported Cisco hardware. Implementing Stronger Algorithms It offers much higher computational resistance than MD5
The MD5 algorithm powering Type 5 passwords was designed in 1991. Today, it is highly susceptible to brute-force acceleration via modern GPUs. Leaving your network infrastructure secured by Type 5 hashes presents a significant compliance and security risk.
In all these cases, "decryption" is the wrong word. You are performing a on your own (or authorized) hashes.
: Conduct a network-wide audit to identify and replace all instances of Type 5, Type 7, and other deprecated types with Type 8 or Type 9.
Instead, recovering a Type 5 password requires . This process involves guessing plaintext combinations, hashing them using the identical salt and algorithm, and checking if the output matches the target hash. How Cisco Type 5 Hashes are Cracked
However, network administrators often seek ways to recover or decrypt passwords for operational or security auditing purposes. The harsh reality is that, unlike Type 7 passwords which can be easily decrypted, Type 5 passwords, due to their hashing, cannot be directly decrypted.