Attack Technique

Brute force

Brute force attacks are a persistent threat in cybersecurity, targeting the weakest link in any security setup — passwords. Here’s what you need to know about this simple-but-effective attack technique.

Definition

Definition

What is a brute force attack?

A brute force attack is a method attackers use to gain unauthorized access to your environment by systematically trying every possible combination of passwords, encryption keys, or PINs until the correct one is found.

This technique relies on sheer computing power to crack passwords or keys, rather than exploiting software vulnerabilities or using social engineering tactics.

How it works

How does brute force work?

There are many different types of brute force attacks including:

Simple Brute Force Attack: Trying all possible combinations without any prior knowledge about the password.
Dictionary Attack: Using a list of common words, phrases, or leaked passwords to guess the correct password.
Hybrid Brute Force Attack: Combining dictionary attacks with random character additions to attempt more complex passwords.
Reverse Brute Force Attack: Starting with a known password (often a common one) and searching for a username that matches.

Because this technique relies on volume, attackers often combine different methods to increase the chance of success with a hybrid brute force attack. For example, they might start with a dictionary attack and then append numbers or change characters to test multiple combinations.

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Why attackers use it

Why do attackers use brute force?

Attackers use brute force methods to gain unauthorized access to accounts, systems, or encrypted data by systematically trying all possible combinations of passwords or keys until the correct one is found. Brute force attacks exploit weak passwords, lack of account lockout policies, and insufficient security measures to infiltrate systems. Here are the primary reasons why attackers employ brute force attacks:

Unauthorized Access to Accounts

‍Password Cracking: Attackers attempt to guess user passwords to access email accounts, social media, banking, or corporate systems.
‍Credential Stuffing: Using leaked username and password combinations from other breaches to access accounts where users may have reused credentials.

Data Theft and Espionage

‍Access to Sensitive Information: Once inside a system, attackers can steal confidential data such as personal information, financial records, or intellectual property.
Corporate Espionage: Gaining access to a competitor's systems to obtain trade secrets or strategic plans.

System Compromise and Control

Installing Malware: After gaining access, attackers can install malware, ransomware, or create backdoors for persistent access.
Botnet Creation: Compromised systems can become part of a botnet used for large-scale attacks like Distributed Denial of Service (DDoS).

Financial Gain

Monetary Transactions: Unauthorized access to financial accounts enables attackers to transfer funds or make fraudulent purchases.
Selling Access: Compromised accounts and systems can be sold on the dark web to other malicious actors.

Exploitation of Weak Security Practices

Weak Passwords: Many users employ simple, common passwords that are easily guessable.
Lack of Account Lockout Policies: Systems without mechanisms to lock accounts after multiple failed login attempts are more susceptible.

Automated Tools and Increased Computing Power

Availability of Tools: Numerous tools automate brute force attacks, making it easier for attackers with varying skill levels.
Advanced Hardware: High computing power allows attackers to perform a vast number of attempts in a short period, increasing the chances of success.

Testing System Defenses

Reconnaissance: Attackers may use brute force methods to probe systems and identify vulnerabilities or weak points in security protocols.

Why Brute Force Attacks are Attractive to Attackers

Simplicity: Brute force attacks do not require sophisticated hacking skills and can be executed using readily available tools.
Potential High Reward: Successfully accessing a system can lead to significant financial gain or valuable data extraction.
Low Barrier to Entry: Even inexperienced attackers can perform brute force attacks due to the abundance of resources and tutorials available online.
Anonymity: Attackers can mask their identities using proxy servers or VPNs, reducing the risk of being caught.

Platform Detections

How to detect activities related to brute force attacks

Taking steps to prevent brute force attacks — like enforcing strong password policies, account lockouts, and access controls — is a must. But what happens when an attacker bypasses MFA or slips past your prevention tools with successful credential stuffing?

You need to know what’s happening inside your environment. For that, AI-driven detections are key.

Vectra AI has built powerful detections designed to find brute force attempts based on attacker behaviors. These range from a basic brute force detection to models that focus on SMB, Kerberos, and Entra ID. Each one shows SOC analysts exactly what attackers are up to so you know what to investigate, and when.