Practical Network Scanning

Password policies

Passwords are an important characteristic of computer security. A poorly constructed, weak password may result in unauthorized access or exploitation of organization IT resources. This password construction guideline applies to all passwords, including (but not limited to) user-level accounts, system-level accounts, web accounts, email accounts, and local router logins. On a Windows system, you can run secpol.msc from the Command Prompt: 

Strong passwords have the following characteristics:

• They contain at least twelve alphanumeric characters
• They contain both upper and lowercase letters
• They contain at least one number ...