Information
Use the enable secret command to provide an additional layer of security over the enable password. The enable secret command provides better security by storing the enable secret password using a nonreversible cryptographic function. The added layer of security encryption provides is useful in environments where the password crosses the network or is stored on a TFTP server.
In Cisco IOS XE, password types 8 and 9 are considered more secure than older password types because they use strong hashing algorithms.
- Type 8 passwords use PBKDF2 with SHA-256, which is an improvement over older MD5-based hashing methods.
- Type 9 passwords use SCRYPT, which is designed to be memory-intensive, making it harder for attackers to brute-force.
Cisco generally recommends using Type 8 or Type 9 for better security, but Type 9 is the default in IOS XE. However, some auditors may prefer Type 8 because Type 9 is not NIST-approved, especially in U.S. Defense and Public Sector environments.
Solution
Configure a strong, enable secret password.
hostname(config)#enable secret 9 {ENABLE_SECRET_PASSWORD}
Impact:
While enable secret in Cisco IOS XE enhances security, it can have some potential drawbacks:
- Password Recovery Complexity: If the password is lost, recovering access can be difficult,
- Performance Overhead: Stronger hashing algorithms (like SCRYPT) can slightly increase CPU usage, especially on older hardware.
- Configuration Management Issues: If not properly documented, administrators may struggle with access control changes.
- Potential Lockout Risks: If centralized authentication fails and the enable secret is unknown, network administrators could be locked out.
- Security Misconfiguration: If weak passwords are used, even with encryption, attackers could still brute-force them.