Password Spraying

Distributed Password Spraying via Authentication Failures Across Multiple Accounts

Multi-factor Authentication: Multi-Factor Authentication (MFA) enhances security by requiring users to provide at least two forms of verification to prove their identity before granting access. These factors typically include:

• Something you know: Passwords, PINs.
• Something you have: Physical tokens, smartphone authenticator apps.
• Something you are: Biometric data such as fingerprints, facial recognition, or retinal scans.

Implementing MFA across all critical systems and services ensures robust protection against account takeover and unauthorized access. This mitigation can be implemented through the following measures:

Identity and Access Management (IAM):

• Use IAM solutions like Azure Active Directory, Okta, or AWS IAM to enforce MFA policies for all user logins, especially for privileged roles.
• Enable conditional access policies to enforce MFA for risky sign-ins (e.g., unfamiliar devices, geolocations).
• Enable Conditional Access policies to only allow logins from trusted devices, such as those enrolled in Intune or joined via Hybrid/Entra.

Authentication Tools and Methods:

• Use authenticator applications such as Google Authenticator, Microsoft Authenticator, or Authy for time-based one-time passwords (TOTP).
• Deploy hardware-based tokens like YubiKey, RSA SecurID, or smart cards for additional security.
• Enforce biometric authentication for compatible devices and applications.

Secure Legacy Systems:

• Integrate MFA solutions with older systems using third-party tools like Duo Security or Thales SafeNet.
• Enable RADIUS/NPS servers to facilitate MFA for VPNs, RDP, and other network logins.

Monitoring and Alerting:

• Use SIEM tools to monitor failed MFA attempts, login anomalies, or brute-force attempts against MFA systems.
• Implement alerts for suspicious MFA activities, such as repeated failed codes or new device registrations.

Training and Policy Enforcement:

• Educate employees on the importance of MFA and secure authenticator usage.
• Enforce policies that require MFA on all critical systems, especially for remote access, privileged accounts, and cloud applications.

Password Policies: Set and enforce secure password policies for accounts to reduce the likelihood of unauthorized access. Strong password policies include enforcing password complexity, requiring regular password changes, and preventing password reuse. This mitigation can be implemented through the following measures:

Windows Systems:

• Use Group Policy Management Console (GPMC) to configure:
  • Minimum password length (e.g., 12+ characters).
  • Password complexity requirements.
  • Password history (e.g., disallow last 24 passwords).
  • Account lockout duration and thresholds.

Linux Systems:

• Configure Pluggable Authentication Modules (PAM):
• Use pam_pwquality to enforce complexity and length requirements.
• Implement pam_tally2 or pam_faillock for account lockouts.
• Use pwunconv to disable password reuse.

Password Managers:

• Enforce usage of enterprise password managers (e.g., Bitwarden, 1Password, LastPass) to generate and store strong passwords.

Password Blacklisting:

• Use tools like Have I Been Pwned password checks or NIST-based blacklist solutions to prevent users from setting compromised passwords.

Regular Auditing:

• Periodically audit password policies and account configurations to ensure compliance using tools like LAPS (Local Admin Password Solution) and vulnerability scanners.

Tools for Implementation

Windows:

• Group Policy Management Console (GPMC): Enforce password policies.
• Microsoft Local Administrator Password Solution (LAPS): Enforce random, unique admin passwords.

Linux/macOS:

• PAM Modules (pam_pwquality, pam_tally2, pam_faillock): Enforce password rules.
• Lynis: Audit password policies and system configurations.

Cross-Platform:

• Password Managers (Bitwarden, 1Password, KeePass): Manage and enforce strong passwords.
• Have I Been Pwned API: Prevent the use of breached passwords.
• NIST SP 800-63B compliant tools: Enforce password guidelines and blacklisting.

Account Use Policies: Account Use Policies help mitigate unauthorized access by configuring and enforcing rules that govern how and when accounts can be used. These policies include enforcing account lockout mechanisms, restricting login times, and setting inactivity timeouts. Proper configuration of these policies reduces the risk of brute-force attacks, credential theft, and unauthorized access by limiting the opportunities for malicious actors to exploit accounts. This mitigation can be implemented through the following measures:

Account Lockout Policies:

• Implementation: Configure account lockout settings so that after a defined number of failed login attempts (e.g., 3-5 attempts), the account is locked for a specific time period (e.g., 15 minutes) or requires an administrator to unlock it.
• Use Case: This prevents brute-force attacks by limiting how many incorrect password attempts can be made before the account is temporarily disabled, reducing the likelihood of an attacker successfully guessing a password.

Login Time Restrictions:

• Implementation: Set up login time policies to restrict when users or groups can log into systems. For example, only allowing login during standard business hours (e.g., 8 AM to 6 PM) for non-administrative accounts.
• Use Case: This prevents unauthorized access outside of approved working hours, where login attempts might be more suspicious or harder to monitor. For example, if an account that is only supposed to be active during the day logs in at 2 AM, it should raise an alert or be blocked.

Inactivity Timeout and Session Termination:

• Implementation: Enforce session timeouts after a period of inactivity (e.g., 10-15 minutes) and require users to re-authenticate if they wish to resume the session.
• Use Case: This policy prevents attackers from hijacking active sessions left unattended. For example, if an employee walks away from their computer without locking it, an attacker with physical access to the system would be unable to exploit the session.

Password Aging Policies:

• Implementation: Enforce password aging rules, requiring users to change their passwords after a defined period (e.g., 90 days) and ensure passwords are not reused by maintaining a password history.
• Use Case: This limits the risk of compromised passwords being used indefinitely. Regular password changes make it more difficult for attackers to reuse stolen credentials.

Account Expiration and Deactivation:

• Implementation: Configure user accounts, especially for temporary or contract workers, to automatically expire after a set date or event. Accounts that remain unused for a specific period should be deactivated automatically.
• Use Case: This prevents dormant accounts from becoming an attack vector. For example, an attacker can exploit unused accounts if they are not properly monitored or deactivated.

Tools for Implementation:

• Group Policy Objects (GPOs) in Windows: To enforce account lockout thresholds, login time restrictions, session timeouts, and password policies.
• Identity and Access Management (IAM) solutions: For centralized management of user accounts, session policies, and automated deactivation of accounts.
• Security Information and Event Management (SIEM) platforms: To monitor and alert on unusual login activity, such as failed logins or out-of-hours access attempts.
• Multi-Factor Authentication (MFA) Tools: To further enforce secure login attempts, preventing brute-force or credential stuffing attacks.