Brute Force Attacks: Latest Cases & How to Protect Your Business

Cyberattacks are growing smarter every year and are expected to grow 15% in the next two years.

But sometimes hackers still rely on one of the oldest and most aggressive hacking methods – the brute force attack. It may sound basic, but it remains one of the most common and dangerous ways to break into accounts, networks, firewalls, and cloud services. And as recent global security advisories show, brute force attacks are scaling bigger than ever.

In this blog, we’ll explore what a brute force attack is, how it works, the latest real-world examples, and what you can do to protect your organization.

What is a Brute Force Attack?

A brute force attack is a hacking technique where an attacker repeatedly tries different passwords or key combinations until the correct one is found.

It’s like trying every possible key on a lock; eventually, one will open the door. Hackers rely on automation and computational power to make millions of attempts per second, enabling them to break into digital systems.

Cybercriminals use automated brute force software to speed up these attacks. These tools can attempt huge password combinations against servers, VPNs, firewalls, and websites without needing any manual effort.

What is Brute Force Algorithm?

The method used by attackers to compute millions of password combinations is often called a brute force algorithm. This algorithm tries every possible combination in a systematic order, be it numbers, letters, special characters, patterns, until a perfect match is found. When applied with large computing clusters or distributed botnets, even long passwords can fall in less time than expected.

Reverse Brute Force Attack – A Rising Trend

Did you know there’s another rising trend of reverse brute force attacks, which is another technique to hack an account?

Opposite to brute force attacks, where a single account is hacked by using a combination of different passwords, a reverse brute force attack uses one common password for millions of usernames. For example, the attacker takes one commonly used password, say, Admin@123 and try this password across multiple usernames.

Because many organizations still rely on predictable password patterns, this technique allows hackers to break into large numbers of accounts quickly without triggering account lockouts or rate-limit rules.

How Does a Brute Force Attack Work?

To understand How this work, imagine a bot continuously guessing login credentials like admin123, admin@123, Admin!2024, and so on. When the login finally succeeds, the attacker gains access to private systems. This may lead to data theft, system shutdown, ransomware attacks, or taking full control of accounts.

Once inside, attackers might go further by using the compromised access to move through networks. They can bypass more security controls, install malware or spyware, or exfiltrate sensitive business data.

Why Brute Force Attacks Are Getting Worse?

Even though many organizations are more aware of cybersecurity, hackers are scaling these attacks faster than before. Global botnets and proxy networks now allow attackers to use millions of IP addresses to launch high-speed password-guessing attacks without getting blocked easily.

Weak passwords continue to make this attack extremely effective.

Types of Brute Force Attack

Some common forms of brute force attack include:

• Simple brute force – Trying all possible passwords without logic
• Dictionary attacks – Using words from a dictionary or leaked password lists
• Password spraying – Trying a few common passwords across thousands of accounts to avoid detection
• Credential stuffing – Using usernames and passwords stolen from other websites
• Hybrid brute force – Combining dictionary words with numbers or special characters

Attackers may use a brute force attacks software tailored for each method, depending on their target.

Brute Force Attacks in 2025

Unfortunately, 2025 has seen a spike in brute force attacks in cybersecurity, exposing weaknesses in even the most trusted security brands. Below are some major incidents.

1. Attack on SonicWall Cloud Backup Service

In September 2025, SonicWall issued an urgent advisory warning customers that hackers were conducting brute force attacks against cloud backup service infrastructure via the MySonicWall.com portal. The investigation revealed that hackers accessed around 5% of firewall backup preference files. Although stored credentials were encrypted, the files contained technical configurations that could help attackers exploit firewall devices.

2. 2.8 Million IPs Used in Massive Global Attack on VPN Devices

In February 2025, researchers from The Shadowserver Foundation flagged a massive brute force password cracking attack involving 2.8 million IP addresses per day. The attack targeted VPN and firewall devices from major vendors like Ivanti, SonicWall, and Palo Alto Networks. Many of the source IP addresses were linked to compromised routers and IoT devices, especially in Brazil, Russia, Turkey, Argentina, and Mexico. Since these devices acted as residential proxies, malicious traffic appeared normal, making it extremely difficult for businesses to detect or block.

3. Ukrainian Network FDN3 Linked to Large-Scale Password Attacks

In June-July 2025, cybersecurity company Intrinsec traced aggressive brute force and password spraying campaigns against SSL VPN and RDP devices to autonomous system FDN3 (Ukraine).

The infrastructure was linked to bulletproof hosting services spread across Ukraine and Seychelles – networks well known for supporting malware distribution and ransomware operations.

Researchers found overlaps with cybercriminal groups using brute force attacks as the first step to deploy ransomware in corporate environments.

How to Detect Brute Force Attacks?

Early detection is critical. Security teams should watch for:

• Sudden spike in failed login attempts
• Login attempts from unusual IP locations or anonymous proxy networks
• Repeated access attempts targeting admin accounts
• Login attempts happening 24/7 without user patterns
• Multiple login attempts across different systems using the same password

Companies can use SIEM tools, IP allowlists, MFA and login throttling to fight off attacks before they turn into breaches.

How to Protect Your Business From Brute Force Attacks: Best Practices

To protect business systems, security experts recommend the following:

• Enforce MFA on all accounts, especially external access systems.
• Disable remote admin portals when not needed.
• Set strict login attempt limits and auto-lock rules.
• Use CAPTCHAs and bot-blocking security features.
• Apply firmware and patch updates quickly- firewalls and VPN devices are big targets.
• Use long passwords with random combinations rather than predictable patterns.
• Store passwords securely using salted and hashed methods.

Training employees is equally important. Password hygiene and avoiding reuse across platforms significantly reduce risk.

Conclusion

Brute force attacks may be one of the oldest tricks in the hacking world, but they remain one of the most dangerous. As seen in recent incidents involving cloud firewalls, VPN appliances, and remote access devices, attackers are now combining automation, botnets, and global proxy networks to bypass detection and overwhelm security defenses.

Organizations can’t afford to take this lightly. Strong authentication practices, patching, firewalls, MFA, and continuous monitoring remain the strongest defense. Cybersecurity isn’t about one big fix – it’s about constant vigilance.