What is a brute force attack?
A brute force attack is a cybersecurity threat where a hacker attempts to access a system by systematically testing different passwords until a correct set of credentials is identified.
These attacks are a simple and effective method to exploit weak passwords and poorly secured accounts. They leverage computational power and persistence to try numerous combinations, often using automated tools, and are incredibly effective. According to a 2024 report from Verizon, 77% of attacks against web applications entail stolen credentials or brute force attacks.
Due to the persistently exposed nature of websites and cloud providers, brute force attacks have become one of the most common attack vectors. Anything online protected by passwords, such as login pages, encrypted data, and other security mechanisms, can become a target for malicious actors using this method, making it crucial for businesses to understand how these attacks work and how to stop them.
How does a brute force attack work?
Brute force attacks in their most basic form iterate through every possible combination of characters until a password or encryption key is identified. More advanced versions attempt to get a faster match by starting with simple and commonly used passwords from a file and then resorting to an exhaustive search. Automated tools help speed up this process by generating and testing thousands of combinations per second.
Simple and easy-to-guess passwords are quickly discovered, while longer, more complicated passwords are time-consuming and resource-intensive. However, if the targeted system has no mechanism to detect or block repeated failed login attempts, the attacks can continue indefinitely, increasing the hacker’s chances of eventually finding the correct password.
These attacks go far beyond traditional login pages. They can target cloud service APIs using automated scripts to repeatedly guess API keys or credentials. They can also be used to guess database login credentials or even cloud admin accounts, giving attackers in-depth access to cloud infrastructure.
Once an attacker is in, they can grab sensitive data, disrupt services by altering configurations, or even launch further attacks on other organizations from the compromised system.
Why do attackers resort to brute force attacks?
Contrary to common misconceptions, brute force attacks are not just a last-resort tactic for hackers. They often start with brute force, given their remarkable effectiveness, especially against targets with weak or reused passwords. Despite being well-known as a risky practice, 75% of people globally have poor password habits including weak or reused passwords.
Unfortunately, these bad practices are not just limited to personal accounts. Cloud services and other infrastructure elements frequently rely on machine credentials to facilitate system interconnections. Improper configuration of these services can lead to the use of weak passwords.
For example, a common scenario is speeding up the configuration process by using a simple password like “password1” during setup. Unfortunately, due to inadequate configuration controls, these weak passwords may inadvertently remain in use, even in production environments.
However, even for systems that have hardened security, there are a few core reasons why attackers may still leverage brute force attacks:
Simplicity: These attacks are straightforward to execute via automated tools and do not require sophisticated hacking skills.
Effectiveness: Despite being basic, they can be effective, especially against weak passwords and systems without adequate security measures like account lockouts or rate limiting.
Ability to exploit security weaknesses: Brute force attacks can exploit the lack of strong password policies or lack of security features like multi-factor authentication.
Broad applicability: They can be used against any system protected by a password, making them a versatile tool in a hacker’s arsenal.
Access to valuable data: Successful access to a cloud account can give malicious actors valuable information and control over sensitive cloud resources and services.
Key objectives of brute force attacks
Brute force attacks are not random; they are deliberate attempts to breach security systems with clear objectives in mind. Attackers use them to:
1. Gain unauthorized access to accounts and systems
Attackers leverage brute force techniques to systematically crack passwords and authentication mechanisms, which allows them to infiltrate accounts, servers, or cloud environments.
Once inside, they can escalate privileges, modify settings, or disable security controls. This access enables them to steal data, install malware, or use compromised accounts as a foothold for further attacks.
2. Steal sensitive data and credentials
Brute force attacks are frequently used to gain access to sensitive financial data, personal information, and confidential business records.
Once attackers crack an account, they can exfiltrate credentials and sell them on the dark web or use them in credential-stuffing attacks to compromise other systems where users have used the same password. This stolen data may be leveraged for identity theft, financial fraud, or further cyber intrusions.
3. Compromise cloud services and infrastructure
Brute force attacks often target cloud management interfaces, API keys, and databases to exploit weak or exposed credentials. Once attackers gain access, they can manipulate cloud environments by deploying malware, extracting sensitive data, or modifying system configurations.
They may also create new user accounts with elevated privileges, which allows them to maintain persistent access even if the initial breach is detected. This foothold enables them to expand their control, disrupt operations, or pivot to attack additional cloud assets.
4. Enable further cyber attacks
A successful brute force attack isn’t just a one-time breach—it’s an entry point for even more dangerous threats. Once attackers gain access, they can lock down critical files with ransomware, demanding payment for their release. They might also pull your systems into a botnet, launching massive DDoS attacks or flooding inboxes with spam.
Even worse, compromised accounts give hackers a trusted disguise. They can send phishing emails straight from an internal address, tricking employees or customers into handing over credentials or making fraudulent payments.
5. Disrupt services and operations
By triggering repeated failed logins, attackers can deliberately lock users out of their accounts and disrupt business operations. Similarly, they can overwhelm the authentication system with rapid login attempts, which can also cause service slowdowns or outages.
Either scenario can strain IT resources, delay critical workflows, and create security blind spots that attackers can exploit further. Therefore, brute force attacks can be used as a form of denial-of-service (DoS).
6. Hijack accounts for ad fraud and monetization
Cybercriminals use brute force attacks to seize control of social media, advertising, and e-commerce accounts—turning them into tools for fraud and profit. Once inside, they can run fake ads, siphon ad revenue into their own accounts, and spread malware through malicious links. By manipulating ad campaigns, they drive up costs, inflate engagement metrics, and exploit brand trust to deceive customers.
Hijacked accounts can also be used for impersonation scams, where attackers pose as legitimate businesses to trick users into making payments or handing over sensitive information.
7. Damage brand reputation and trust
Brute force attacks can compromise business accounts, allowing attackers to deface websites, spread disinformation, or hijack official communication channels to damage a brand’s reputation. A security breach can erode customer trust, especially if sensitive data is leaked or misused.
Beyond reputational harm, organizations may face regulatory scrutiny, legal penalties, and financial losses due to non-compliance, incident response costs, and customer churn.
Types of brute force attacks
Brute force attacks have evolved significantly over the years, creating different variations to creatively shorten the number of guesses a hacker has to make to gain access.
Traditional brute force attacks
The most basic version of a brute force attack, this method will attempt every possible combination of characters to discover a password. It relies on the fact that a solution will eventually be found if given enough time, although the time necessary increases with more complex and longer passwords.
Dictionary attacks
To speed things up, attackers can use words from a dictionary or common passwords from breaches. These dictionaries are not the same as traditional dictionaries; instead, they are pre-computed files of passwords to iterate through when implementing a brute force attack.
A more complex variant is called a rainbow table attack, which uses a combination of passwords and their hashes to target stolen hash values, enabling a creative way to crack these files.
Hybrid brute force attacks
Hybrid brute force attacks blend dictionary-based guessing with traditional brute force techniques to crack passwords. Instead of testing every possible combination, attackers start with common words or phrases from a dictionary and then apply variations, such as adding numbers, symbols, or capitalizing letters (e.g., changing "password" to "Password123!" or "P@ssw0rd").
This method speeds up the attack by prioritizing likely password patterns before resorting to a full brute force approach. Since many users create passwords by slightly modifying common words, hybrid attacks can be highly effective at bypassing weak security measures.
Reverse brute force attacks (password spraying)
A more advanced variant of the dictionary attack, these use a handful of common passwords against many accounts. Reverse brute force attacks target users who commonly utilize birthdays, names, cities, sports teams, and a selection of easy-to-guess passwords such as “password1,” “qwerty,” and “123456.”
Testing just a few passwords against many different accounts circumvents protections that lock out accounts after several missed password attempts.
Credential stuffing
Like password spraying, credential stuffing uses a trick to speed up the attack. These attacks use stolen usernames and passwords from different breaches to target people and systems that reuse credentials. With 62% of people reusing passwords for multiple online accounts, these attacks have become a common attack vector.
Cloud-specific attacks
As cloud infrastructure is often more exposed to the outside, malicious actors may implement brute force attacks to specifically target cloud operations. These brute force attacks prey upon different aspects of cloud operations, such as:
Cloud management interfaces: Attackers may attempt to access cloud administration panels to gain control over cloud resources.
API endpoints: Brute force attacks can target API keys or credentials crucial for accessing cloud services.
Cloud-based databases: Repeatedly guessing database login credentials can allow hackers to gain access to stored data.
Common tools used for brute force attacks
A wide range of tools exist to automate brute force attacks and support the different attack types. Some offer broad flexibility, while others are laser-focused on a specific attack style or user skill level.
| Tool | Description |
|---|---|
| Hydra | A highly versatile tool operated via the command line and a globally unique identifier (GUID), Hydra supports many protocols, including FTP, SSH, and HTTP(S). Its key strength is its ability to conduct parallelized attacks, significantly speeding up the brute force process. However, this tool is not simple to use, especially for beginners. |
| Aircrack-ng | This specialized tool for breaking Wi-Fi security codes effectively cracks WEP, WPA, and WPA2-PSK keys. It can also perform packet capture and injection attacks, making it a versatile wireless security tool. |
| John the Ripper | Despite being almost 30 years old, this tool is effective at complex password cracking and supports numerous hash types and platforms, including Unix, Windows, and OpenVMS. It uses different brute force methods such as dictionary attacks and rainbow tables to quickly identify weak passwords. However, this tool’s complexity requires technical expertise. |
| Hashcat | Well known for speed, Hashcat can leverage GPU support to target specific algorithms, including MD4, MD5, and the SHA family. While GPU acceleration makes it extremely fast for certain algorithms, not all are optimized for GPU processing, making them slower to crack. |
| Ncrack | Ncrack enables network authentication cracking across several protocols, such as SSH, RDP, FTP, Telnet, and HTTP(S). Its flexible engine adapts its behavior based on network feedback and can conduct simultaneous attacks on multiple hosts, efficiently identifying weak passwords on networked systems. |
Top countermeasures for brute force attacks
The primary goal of brute force attack countermeasures is to slow down attacks and limit repeated unauthorized attempts, which makes breaches more difficult and resource-intensive. The following strategies can help organizations strengthen defenses, protect sensitive data, and maintain system security.
Example of a brute force attack attempt on a finance application
Enforce multi-factor authentication (MFA): Passwords alone are too easy to crack. Adding MFA significantly reduces the risk of unauthorized access, even if credentials are compromised.
Block automated attacks: Implement rate limiting, account lockouts, and CAPTCHAs to prevent attackers from making unlimited login attempts. These measures slow down brute force efforts and make mass guessing impractical.
Detect and respond in real time: Use security monitoring tools to detect unusual access patterns, repeated failed logins, and potential brute force attempts. Cloud-native solutions and CASBs provide added visibility into cloud-based threats.
Reduce password risks: Encourage the use of password managers to generate and store unique credentials, minimizing weak or reused passwords that attackers exploit.
Train users to recognize threats: Brute force attacks often lead to phishing and credential theft. Security awareness training helps users identify suspicious login attempts and social engineering tactics before they escalate.
Detecting brute force attacks in the cloud
Wiz’s CNAPP solution plays a pivotal role in the detection and response to brute force attacks in cloud environments. Wiz's Cloud Detection and Response (CDR) features allows customers to detect emerging cloud threats in real-time, including successful brute-force attacks on specific user accounts. Furthermore, Wiz can alert organizations about SSH brute force attacks attempted on publicly exposed assets that allow password authentication and have high permissions.
Security Graph: Wiz utilizes a Security Graph to discover and correlate events across an organization's cloud environment. This allows Wiz to identify patterns indicative of brute force attempts, such as a high volume of login failures from a single source.
Contextualization: Wiz doesn't just detect the attack; it provides context. For instance, Wiz can alert on an SSH brute force attack targeting a publicly exposed server with high permissions. This critical context helps security teams prioritize and respond to the most impactful threats.
Integrations: Wiz integrates with security tools like Google Cloud's Security Command Center (SCC). This integration allows security teams to view brute force attacks detected by SCC within the Wiz Security Graph, providing a unified view of security events.
See Wiz in action. Get a personalized demo today to learn how to protect your cloud infrastructure against brute force attacks.