Shared Account Security: Protecting User Credentials

TL;DR

Users sharing passwords is a huge risk. This guide covers strategies to detect and prevent this, focusing on multi-factor authentication (MFA), session management, anomaly detection, user education, and account monitoring. It’s about making accounts harder to compromise even if credentials are leaked.

1. Implement Multi-Factor Authentication (MFA)

This is the single most effective step. Even if a password is shared, MFA adds another layer of security that makes it much harder for an attacker to gain access.

• Choose strong MFA methods: Avoid SMS-based MFA where possible (SIM swapping attacks are common). Prefer authenticator apps (Google Authenticator, Authy), hardware security keys (YubiKey), or platform authenticators (Windows Hello, Touch ID).
• Enforce MFA for all users: Don’t make it optional.
• Consider risk-based MFA: Prompt for MFA more often when a user logs in from an unusual location or device.

Example (using Google Authenticator):

# This is conceptual - implementation varies by system

2. Robust Session Management

How your application handles user sessions impacts security.

• Session timeouts: Shorten session lifetimes to reduce the window of opportunity for a compromised account.
• Invalidate sessions on password change: Force users to re-authenticate after changing their password.
• IP address binding (with caution): Tie a session to a specific IP address. This can be disruptive if users travel, so use it carefully and allow for trusted IP ranges.
• User agent string tracking: Monitor changes in the user agent string during a session – a sudden change could indicate account takeover.

Example (session timeout configuration – conceptual):

# Session lifetime set to 30 minutes

3. Anomaly Detection

Look for unusual activity that might indicate a shared account.

• Failed login attempts: Monitor for repeated failed logins, especially from different locations.
• Simultaneous logins: Detect when the same account is logged in from multiple locations at the same time. This is a strong indicator of compromise.
• Unusual access patterns: Track which resources users are accessing and flag any deviations from their normal behaviour.
• Geographic location monitoring: Alert on logins from unexpected countries or regions.

Example (detecting simultaneous logins – conceptual):

# Check for multiple active sessions per user

4. User Education

Teach users about the risks of sharing their credentials.

• Regular security awareness training: Explain why password sharing is dangerous and the consequences it can have.
• Phishing simulations: Help users identify phishing attacks that attempt to steal their passwords.
• Password management tools: Encourage users to use strong, unique passwords generated by a reputable password manager.

5. Account Monitoring and Auditing

Regularly review account activity for suspicious behaviour.

• Audit logs: Enable detailed audit logging that records all login attempts, password changes, and access to sensitive resources.
• Automated alerts: Set up automated alerts to notify administrators of any suspicious activity.
• Regular reviews: Periodically review user accounts and permissions to ensure they are still appropriate.

Example (audit log entry – conceptual):

# Log entry showing a successful login from a new location

6. Consider Passwordless Authentication

Where feasible, move away from passwords altogether.

• Biometric authentication: Use fingerprint or facial recognition.
• Magic links: Send a unique link to the user’s email address that allows them to log in without a password.
• Passkeys: A modern standard for secure, passwordless login using cryptographic keys stored on devices.