Brute Force Attacks
What Are They, What Are the Indicators and How to Prevent Them What Are Brute Force Attacks?
A brute force attack is a hacking method that involves systematically guessing usernames, passwords, or cryptographic keys through trial and error. Attackers try every possible combination until they successfully gain access to a system, account, or encrypted information. These attacks can be conducted manually or through automated tools that can attempt thousands or millions of guesses in a short period.
Types of Attacks
Simple Brute Force
Attackers attempt to guess a password based purely on trial and error without using any information
Dictionary Attacks
Attackers use a list of commonly used passwords or words found in dictionaries.
Hybrid Attacks
A combination of a dictionary attack and brute force, where common passwords are combined with numbers and symbols.
Reverse Brute Force
Attackers start with a known password and attempt to guess the correct username.
Credential Stuffing
Attackers use credentials from previously leaked breaches to try on other websites.
Main Indicators
Multiple Failed Login Attempts
A high number of unsuccessful login attempts in a short period, particularly for the same user account or from the same IP address, suggests that an attacker may be trying to guess a password.
Unusual Login Patterns
Repeated login attempts across multiple accounts from the same IP address or different accounts being targeted sequentially. The attacker may use automated tools to cycle through various usernames.
Account Lockouts
Frequent or unexpected account lockouts can be a sign of brute force attacks. If your system is set to lock an account after several failed attempts, this can indicate that an attacker is attempting to guess passwords.
Unrecognized IP Addresses or Locations
Login attempts from unfamiliar or suspicious geographic locations, especially if these locations don’t match the normal behavior of your users.
High Traffic Volume to Login Pages
An abnormal spike in traffic to login endpoints could indicate that an automated attack tool is being used. This is particularly true if the traffic includes many failed login attempts.
Irregular Times for Login Attempts
If login attempts occur at unusual times (e.g., in the middle of the night for your users’ time zone), this may suggest automated brute force attempts.
Accessing Nonexistent Usernames
Attackers may try to access nonexistent usernames or accounts, indicating they are attempting to guess valid usernames through trial and error.
Unusual Log Entries
Logs may show repetitive login attempts, failed authentications, or login requests with slight variations (such as minor changes in credentials). Reviewing server logs can reveal signs of a brute force attack.
Increased Bandwidth Usage
Some brute force attacks can consume large amounts of bandwidth, especially if an attacker is using a large botnet to conduct the attack from multiple devices or locations.
Login Success After Multiple Failures
If there is a successful login after many failed attempts, it could indicate that the attacker eventually found the correct credentials and successfully breached the system.
How to Prevent Brute Force Attacks
Use Strong Password Policies
Enforce the use of strong, complex passwords that are difficult to guess.
Enable Multi-Factor Authentication (MFA)
MFA adds an extra layer of security by requiring a second form of verification, such as a code sent to the user’s phone or email. Even if an attacker guesses the password, they still won’t be able to access the account without this second factor.
Limit Login Attempts
Set a limit on the number of failed login attempts allowed within a specific time period (e.g., 3-5 attempts). After reaching this limit, temporarily lock the account or require a CAPTCHA to be solved before allowing further attempts.
Use increasing time delays between login attempts after each failure, making brute force attacks slower and less practical.
Implement CAPTCHA
Use CAPTCHA challenges on login pages to distinguish between human users and bots. This makes it difficult for automated scripts to continue guessing passwords.
Monitor Login Activity and Logs
Regularly review logs for failed login attempts, unusual login patterns, or traffic anomalies. Security Information and Event Management (SIEM) systems can automate this process and flag suspicious behavior.
Alert administrators when login attempts from unusual locations or IP addresses occur.
Use IP Blacklisting and Geofencing
Block or blacklist IP addresses after too many failed login attempts. Alternatively, implement rate limiting to slow down repeated login attempts from the same IP address.
Geofencing restricts access to accounts or systems based on geographic location, preventing login attempts from regions where legitimate users are unlikely to be.
Account Lockout Mechanism
After a certain number of failed login attempts, lock the account temporarily (for example, 15-30 minutes) or require user verification through email or phone. This drastically slows down brute force attacks.
Password Hashing and Salting
When storing passwords, use hashing algorithms (e.g., bcrypt, Argon2) and salt them before saving in databases. This ensures that even if an attacker gains access to the password database, they can’t easily reverse-engineer the passwords.
Deploy Intrusion Detection and Prevention Systems (IDPS)
Use IDPS solutions to monitor network traffic and detect unusual activity such as repeated failed login attempts or brute force tools being used. These systems can block suspicious IP addresses or accounts automatically.
Use Account Lockout Notifications
Notify users via email or SMS when their accounts are locked due to multiple failed login attempts, allowing them to be aware of potential brute force attempts on their accounts.
Credential Stuffing Protection
Use tools and services that detect credential stuffing attacks, which are similar to brute force but involve using credentials from known breaches. Solutions like Have I Been Pwned or other databases can help identify when leaked credentials are used.
Session Timeouts
Implement session timeouts that log users out automatically after a period of inactivity. This reduces the risk of brute force attacks attempting to hijack active sessions.
Use Secure Password Managers
Encourage users to use password managers, which allow them to create and store complex passwords securely without needing to remember them. This reduces the likelihood of weak passwords being used.
Educate Users
Provide users with security awareness training on the importance of strong passwords, not reusing passwords, recognizing phishing attempts, and enabling MFA. Educated users are less likely to fall victim to attacks.
By applying these strategies, you can significantly reduce the risk of successful brute force attacks and protect your systems and accounts from unauthorized access.
Monitoring Remote Sessions
Security monitoring is crucial for preventing ransomware attacks as it enables early detection, identification of vulnerabilities, monitoring for anomalies, data protection, and compliance with regulatory requirements.
TSFactory’s RecordTS v7 will record Windows remote sessions reliably and securely for RDS, Citrix and VMware systems. Scalable from small offices with one server to enterprise networks with tens of thousands of desktops and servers, RecordTS integrates seamlessly with the native environment.