An IP address’s reputation is based on its history of suspicious activity. The more IP addresses is observed launching denial-of-service attacks, dropping malware, hosting phishing sites, or distributing illegal or obscene material, the more it will be categorized as malicious. Additionally, if the IP is associated with other malicious domains, locations, or internet objects in the past, it will also be classified as a riskier threat.

Suspicious activity and behavior can include brute force attempts, excessive logins, pinging or scanning, cryptocurrency mining, public cloud, anonymizers, and other suspicious activities that may signal a cyberattack. IPs that engage in these activities are often flagged by email providers, websites, and other online services.

Best Practices for Maintaining a Malicious IP List for Threat Prevention

Malicious IP List often appear in large clusters, indicating that they are sharing similar characteristics. For example, they may all be connected to the same network, or a group of them could share a common IP block range.

Some of the most common types of malicious IPs are botnets, phishing sites, DDoS attackers, and malware distribution IPs (which describe devices that malicious actors use to spread ransomware, spam emails, or other infections).

Being proactive is the best way to avoid being targeted by bad actors. This involves leveraging comprehensive blacklists, regular software updates, and a strong firewall defense system to help keep your organization’s digital infrastructure safe from threats.