Password Guessing Attack Prevention

TL;DR

Yes, a malicious actor *could* attempt to lock you out by repeatedly trying incorrect passwords. However, modern systems have protections against this. We’ll cover how these work and what extra steps you can take.

How Password Guessing Attacks Work

An attacker tries many different passwords in quick succession hoping one will be correct. If successful, they gain access. More commonly, they aim to trigger account lockouts, then try social engineering or other methods to regain access (e.g., resetting the password).

Protections Your System Likely Has

1. Rate Limiting: Most systems limit how many login attempts are allowed within a specific timeframe (e.g., 5 attempts in 10 minutes). After too many failures, the account is locked for a period.
2. Account Lockout Policies: These define when an account locks and for how long. They’re often configurable by administrators.
3. CAPTCHAs/Multi-Factor Authentication (MFA): CAPTCHAs require human verification, slowing down automated attacks. MFA adds another layer of security beyond just a password.
4. Brute Force Detection: Some systems monitor for unusual login patterns and can automatically block suspicious activity.

Steps to Improve Your Security

1. Enable Multi-Factor Authentication (MFA): This is the single most effective step. Even if an attacker guesses your password, they’ll need a second factor (e.g., code from an app, SMS code) to log in.
2. Use Strong, Unique Passwords: A long, complex password that isn’t used anywhere else is harder to guess.
   • Consider using a password manager to generate and store strong passwords.
3. Check Account Lockout Settings (If you’re an administrator): Ensure your lockout policy is reasonable.
   • Too short of a lockout duration makes the system vulnerable. Too long frustrates legitimate users.
   • Consider logging failed login attempts for auditing purposes.
4. Monitor Login Logs: Regularly review logs for suspicious activity, such as repeated failed logins from unusual locations.
   • Many systems provide tools to help with this monitoring. For example, in Linux you might check /var/log/auth.log or use a tool like fail2ban.

   sudo fail2ban-client status authssh

5. Consider IP Blocking: If you identify an attacker’s IP address, block it at the firewall level.
   • Be careful not to accidentally block legitimate users.
6. Educate Users: Train users about phishing and social engineering attacks that could be used to obtain their passwords.

What if you are locked out?

1. Use the Password Reset Process: Most systems provide a way to reset your password, usually via email or security questions.
2. Contact Support: If you can’t reset your password, contact the service provider’s support team.