Massive Brute Force Attacks Targeting VPNs and Firewalls – How to Stay Protected

In the ever-evolving landscape of cybersecurity, brute force attacks remain one of the most persistent and effective methods used by hackers. Recent reports indicate that a massive brute force campaign is currently underway, leveraging nearly 2.8 million IP addresses daily to target VPNs, firewalls, and other edge security devices from vendors like Palo Alto Networks, Ivanti, and SonicWall. This large-scale attack underscores the urgent need for organizations to strengthen their network defenses against credential-based threats.

Understanding Brute Force Attacks

Brute force attacks occur when cybercriminals systematically attempt to log into devices and systems by trying multiple username-password combinations until they find the correct credentials. Once access is gained, attackers can take control of devices, exfiltrate sensitive data, or even use the compromised system as a foothold for more extensive attacks.

Unlike sophisticated zero-day exploits, brute force attacks don’t require exploiting software vulnerabilities—they instead rely on weak, reused, or default passwords. This makes them especially dangerous for internet-exposed devices that lack robust authentication mechanisms.

The Current Threat: 2.8 Million IPs Engaged in Large-Scale Attacks

According to The Shadowserver Foundation, this massive brute force attack has been ongoing since January, with a staggering 2.8 million unique IP addresses participating daily. The attacks primarily originate from Brazil, Turkey, Russia, Argentina, Morocco, and Mexico, and are aimed at web login pages of edge devices, including:

• Firewalls
• VPNs and remote access gateways
• IoT security appliances

Security researchers believe that many of the attacking IPs are part of a botnet, with compromised MikroTik, Huawei, Cisco, Boa, and ZTE routers acting as the primary attack nodes. These devices are often infected by malware that enables them to launch automated brute force attacks at scale.

How Brute Force Attacks Exploit Edge Devices

Edge devices—such as firewalls and VPN gateways—serve as the first line of defense for corporate networks. However, if misconfigured or left unpatched, they can become prime targets for brute force attacks. Here’s how attackers exploit these devices:

1. Automated Credential Stuffing: Using vast databases of leaked passwords, attackers automate login attempts to gain unauthorized access.
2. Exploitation of Weak or Default Passwords: Devices that use factory-set credentials or weak passwords are easy targets.
3. Leveraging Known Vulnerabilities: Some attackers exploit outdated firmware to bypass authentication mechanisms.
4. Residential Proxy Abuse: Attackers route brute force traffic through residential proxy networks, disguising malicious activity as normal user behavior.

The Consequences of a Successful Brute Force Attack

If attackers manage to breach an edge security device, the consequences can be severe:

• Network Takeover – Compromised firewalls and VPNs can give attackers an open door into an organization’s internal network.
• Data Breaches – Sensitive business information, user credentials, and intellectual property can be stolen.
• Malware Deployment – Attackers can plant ransomware or other malware to maintain persistence within the network.
• Abuse as Proxy Nodes – Hijacked devices can be used as “high-reputation” proxies for further cybercriminal activities.

How to Defend Against Brute Force Attacks

Given the sheer scale of this ongoing attack, organizations must take proactive measures to secure their edge devices. Here’s how:

• Enforce Strong Authentication Practices
  • Implement Multi-Factor Authentication (MFA) to prevent unauthorized access.
  • Require strong, unique passwords for all accounts and disable default credentials.
    
• Restrict Access to Login Interfaces
  • Limit access to VPNs, firewalls, and admin consoles to trusted IP addresses.
    
  • Disable unnecessary remote access protocols and web admin interfaces.
    
• Monitor and Detect Anomalous Activity
  
  • Deploy intrusion detection systems (IDS) to flag repeated failed login attempts.
    
  • Use rate-limiting and CAPTCHA challenges to slow down brute force attempts.
    
• Keep Firmware and Security Patches Up to Date
  
  • Regularly update edge device firmware to patch known vulnerabilities.
    
  • Subscribe to vendor security alerts for immediate response to emerging threats.
    
• Utilize Threat Intelligence and Security Tools
  
  • Deploy behavioral analytics to detect credential stuffing and brute force attempts.
    
  • Use endpoint protection and network segmentation to minimize attack impact.
    

Brute Force Attacks Are Evolving—So Should Your Security

With cybercriminals continuously adapting their techniques, organizations cannot afford to be complacent when it comes to securing their perimeter defenses. TechHorizon Consulting has the expertise in securing edge devices, implementing strong authentication measures, and proactively monitoring for credential-based threats.

If your organization relies on VPNs, firewalls, or remote access devices, now is the time to harden your defenses against brute force attacks. Contact TechHorizon Consulting today to assess your security posture and implement advanced protection strategies against emerging cyber threats.