In the constantly evolving landscape of cybersecurity, defending your systems against attackers requires more than just strong passwords and firewalls. One of the most effective strategies you can employ is to increase the "work factor"—a term that refers to the amount of effort, time, and resources an attacker must expend to compromise a system. By increasing the work factor, you can make your system less attractive to attackers, ultimately forcing them to abandon their efforts and seek out easier targets.
In this post, we'll explore several methods to increase
the work factor and discuss how they can be implemented to strengthen your
system's defenses.
1. Implement Timeout Mechanisms
Timeouts are a simple yet powerful way to increase
the work factor for attackers. When a user (or attacker) enters incorrect
credentials multiple times, the system can implement a timeout, delaying
further attempts for a certain period. This prevents attackers from quickly
cycling through password attempts (brute force attacks) and forces them to slow
down.
Implementation:
•
Login Attempt Timeouts: After a set
number of failed login attempts, impose a delay before allowing further
attempts. For example, after 5 incorrect attempts, impose a 30-second delay.
•
Session Timeouts: Automatically log out
users after a period of inactivity, forcing attackers to restart their efforts
if they gain access to an idle session.
2. Enforce Quota and Rate Limits
Quota and rate limits are another effective way to
increase the work factor. These limits restrict the number of actions that can
be performed in a given time period, making it harder for attackers to execute
automated attacks.
Implementation:
•
API Rate Limiting: Set limits on the
number of API requests that can be made within a certain timeframe. For
example, allow only 100 requests per minute per IP address. This thwarts
attackers who use automated scripts to bombard your system with requests.
•
Password Reset Limits: Limit the number
of password reset requests that can be made in a specific timeframe. This
prevents attackers from abusing the password reset functionality to lock out
legitimate users or gain access to accounts.
3. Use CAPTCHA and Other Human Verification Methods
Adding CAPTCHA challenges or other human verification
methods is a proven way to increase the work factor by ensuring that only human
users (not bots) can interact with your system. This is especially useful for
login forms, registration forms, and other areas where automated attacks are
common.
Implementation:
•
Login CAPTCHAs: Implement a CAPTCHA
challenge after a certain number of failed login attempts or on every login
attempt. This makes it significantly harder for automated scripts to continue
brute-forcing passwords.
•
Registration CAPTCHAs: Require CAPTCHA
completion during user registration to prevent bots from creating fake
accounts.
4. Apply Progressive Delays and Exponential Backoff
Progressive delays and exponential backoff
increase the time between allowed attempts as the number of failed attempts
grows. This strategy greatly increases the work factor by making each
successive attempt take longer than the last, discouraging persistent
attackers.
Implementation:
•
Login Backoff: After each failed login
attempt, increase the delay before the next attempt is allowed. For example,
after 3 failed attempts, wait 10 seconds, after 4, wait 30 seconds, and so on.
•
API Call Backoff: For API requests,
implement exponential backoff on rate limits, gradually increasing the wait
time between requests after each limit breach.
5. Introduce Account Lockout Mechanisms
Account lockouts can be a strong deterrent against
brute force attacks by locking an account after a certain number of failed
login attempts. While this method needs careful implementation to avoid
denial-of-service attacks against legitimate users, it can significantly
increase the work factor for attackers.
Implementation:
•
Temporary Lockouts: After a defined
number of failed login attempts, temporarily lock the account for a period
(e.g., 15 minutes). Notify the user of the lockout and provide instructions for
regaining access.
•
Permanent Lockouts with Administrator
Intervention: For more critical systems, consider locking accounts
permanently after multiple failed attempts, requiring manual intervention by an
administrator to unlock them.
6. Implement Multi-Factor Authentication (MFA)
Multi-Factor Authentication (MFA) adds an additional
layer of security by requiring users to provide multiple forms of verification
(e.g., a password and a one-time code sent to their phone). This drastically
increases the work factor for attackers, as they must compromise more than just
the user’s password.
Implementation:
•
Mandatory MFA: Make MFA mandatory for all
users, especially for accessing sensitive systems or performing critical
actions like changing account details or making financial transactions.
•
Adaptive MFA: Use adaptive MFA, which
requires additional verification only when the system detects unusual behavior,
such as login attempts from a new device or location.
Focus on the Strategic Outcome
Increasing the work factor for attackers is a strategic
approach to improving your system's security. By implementing timeouts, quota
thresholds, human verification methods, and other limits, you can make it
significantly more difficult for attackers to successfully compromise your
system. These measures, while simple, can have a profound impact on the
security of your systems by making them less attractive targets for
cybercriminals. By applying these strategies, you’re not only protecting your
resources but also sending a clear message: attacking your system is simply not
worth the effort.
Remember, the goal is to make the attacker's job so
laborious and time-consuming that they abandon their efforts and move on to
easier prey.
