GreyNoise Intelligence has launched a free web-based tool called GreyNoise IP Check that enables users to determine if their IP address has been observed participating in malicious scanning operations, potentially indicating compromise by botnets or residential proxy networks1. This development represents a significant step in making enterprise-grade threat intelligence accessible to the general public and security professionals alike, providing immediate visibility into potentially compromised network infrastructure.
For security teams, the ability to quickly verify whether their external IP addresses are generating malicious traffic can help identify compromised systems, investigate alert fatigue sources, and maintain network reputation. The tool analyzes the visiting device’s IP address and returns a verdict within seconds, classifying it as clean, suspicious/malicious, or a known business service2. When an IP is flagged as suspicious, the service provides a detailed 90-day activity timeline with specific behavioral tags such as SSH probing or web vulnerability scans, offering context for security analysis and incident response.
GreyNoise Platform Capabilities and Enterprise Value
GreyNoise operates a global sensor network that collects and analyzes internet background noise—the constant scanning and probing activity across public networks. The company’s core mission focuses on distinguishing between benign, widespread scanning and targeted malicious activity, thereby reducing alert fatigue for security operations centers3. This capability has made GreyNoise an essential tool for over 80,000 users, 400+ global government agencies, and 60% of Fortune 1000 companies, including organizations like JPMorgan Chase, Airbus, and Nestlé.
The platform serves multiple security functions within enterprise environments, particularly in security operations where it filters out noisy, low-priority alerts from mass internet scanners. For vulnerability management teams, GreyNoise provides real-time data on active exploitation trends, with the company claiming it detects exploitation faster than official sources like the CISA Known Exploited Vulnerabilities catalog 80% of the time3. Threat hunters benefit from the platform’s comprehensive tagging of all observed activity, enabling rapid queries to identify anomalies and potential threats within network traffic.
Technical Implementation and API Access
The GreyNoise IP Check tool is accessible at check.labs.greynoise.io and requires no authentication or registration, making it immediately usable by technical and non-technical users alike. For security professionals seeking to integrate this capability into automated workflows, GreyNoise provides a no-authentication JSON-returning API that returns structured data about IP reputation2. This API enables organizations to build custom monitoring systems that can automatically check IP addresses against GreyNoise’s database, potentially integrating with existing security orchestration platforms.
When an IP address is identified as suspicious or malicious, the tool provides detailed metadata including the first and last seen timestamps, classification categories, and specific tags describing the observed behavior. This granular information helps security teams understand the nature of the suspicious activity, whether it involves vulnerability scanning, brute force attempts, or participation in specific botnet campaigns. The historical data covering 90 days of activity allows for trend analysis and helps determine if the compromise is ongoing or historical.
Recent Botnet Campaigns Identified by GreyNoise
GreyNoise’s threat intelligence team has recently identified and documented several significant botnet operations demonstrating the scale and sophistication of modern malicious scanning campaigns. In July 2025, analysts discovered a previously untracked scraper botnet variant concentrated primarily in Taiwanese networks4. This botnet, detected using JA4+ network fingerprinting techniques, involved over 3,600 unique IPs with 54% originating from Taiwanese networks, suggesting potentially compromised technology or services widely deployed in the region.
More recently, in October 2025, GreyNoise began tracking a highly coordinated botnet operation targeting U.S. Remote Desktop Protocol infrastructure that reached unprecedented scale5. The campaign initially involved over 100,000 unique IPs from more than 100 countries and escalated to approximately 300,000 IPs within days. The coordinated nature of this attack was evident from nearly all participating IPs sharing similar TCP fingerprints, indicating centralized control by one or more threat actors.
| Campaign | First Observed | Scale | Primary Targets | Key Characteristics |
|---|---|---|---|---|
| Hello-World Scraper Botnet | April 19, 2025 | 3,600+ IPs | US and UK infrastructure | Concentrated in Taiwan (54%), JA4+ fingerprinting detection |
| Coordinated RDP Attack Wave | October 8, 2025 | 300,000+ IPs | US RDP infrastructure | Highly coordinated, shared TCP fingerprints, rapid scaling |
Practical Applications for Security Teams
For security operations centers, the GreyNoise IP Check tool provides immediate value in investigating alerts where external IP addresses are flagged in security monitoring systems. By quickly verifying whether an IP is known to GreyNoise as malicious or part of widespread scanning activity, analysts can prioritize genuine threats over background noise. This capability is particularly valuable for organizations with limited security resources that need to focus their attention on the most critical security events.
Network administrators can use the tool to periodically check their organization’s external IP ranges for signs of compromise, especially following security incidents or when noticing degraded network performance. The detailed activity timeline provided for suspicious IPs can help pinpoint when compromise occurred and what type of malicious activity was detected, informing containment and remediation efforts. For organizations managing remote workers, the tool offers a simple method to check residential IP addresses that might be flagged due to compromised home network equipment.
Broader Impact on Security Posture
The availability of free tools like GreyNoise IP Check contributes to raising overall security awareness and capabilities across the ecosystem. By democratizing access to threat intelligence that was previously available primarily to enterprises with substantial security budgets, GreyNoise helps individual users and smaller organizations improve their security posture. This approach aligns with the company’s stated principle that “no attack should work twice” by sharing intelligence broadly across the security community3.
For organizations concerned about IP reputation damage resulting from compromised systems, the tool provides a mechanism for ongoing monitoring and early detection of issues that could lead to blocking by security services or reputation-based filtering systems. The transparency offered by the detailed activity reports enables more effective communication with internet service providers or hosting companies when addressing compromised systems, providing evidence of malicious activity patterns and timelines.
GreyNoise continues to expand its threat intelligence offerings with products like GreyNoise Block, a fully configurable real-time blocklist product that organizations can use to automate defense against known malicious scanners3. The company has also demonstrated its value in vulnerability management by providing early warning of exploitation trends, such as recently observed spikes in malicious scanning activity targeting Palo Alto Networks GlobalProtect and active exploitation of Fortinet FortiWeb vulnerabilities3.
Conclusion
The launch of GreyNoise IP Check represents a significant advancement in making sophisticated threat intelligence accessible to a broader audience. By providing immediate visibility into whether IP addresses are participating in malicious activity, the tool helps security professionals, network administrators, and individual users identify compromised systems and maintain network reputation. As botnet operations continue to increase in scale and sophistication, tools that provide clear, actionable intelligence about malicious scanning activity become increasingly essential components of a comprehensive security strategy.
GreyNoise’s dual role as both an enterprise security platform and a public resource through free tools demonstrates the value of sharing threat intelligence across the security community. The detailed research on botnet campaigns like the Taiwan-concentrated scraper operation and the massive coordinated RDP attacks provides context for the types of threats that the IP Check tool can help identify. For organizations seeking to improve their security posture, integrating IP reputation checking into regular security monitoring processes can provide early warning of compromises and help reduce alert fatigue from widespread internet scanning activity.
References
- Blackstorm Security on X. “GreyNoise launches free scanner to check if you’re part of a botnet.” November 28, 2025. https://x.com/blackstormsecbr/status/1994205380855935076
- CyberInsider. “Free scanner reveals if your IP address is used for malicious activity.” By Amar Ćemanović. November 26, 2025. https://cyberinsider.com/free-scanner-reveals-if-your-ip-address-is-used-for-malicious-activity/
- GreyNoise Official Website. “GreyNoise Intelligence | Real-Time Intelligence For Modern Threats.” Retrieved November 2025. https://www.greynoise.io/
- GreyNoise Blog. “GreyNoise Identifies New Scraper Botnet Concentrated in Taiwan.” July 9, 2025. https://www.greynoise.io/blog/new-scraper-botnet-concentrated-in-taiwan
- GreyNoise Blog. “100,000+ IP Botnet Launches Coordinated RDP Attack Wave Against US Infrastructure.” By Noah Stone. October 10, 2025 (Updated October 14-15, 2025). https://www.greynoise.io/blog/botnet-launches-coordinated-rdp-attack-wave
- BleepingComputer on X. “GreyNoise launches free scanner to check if you’re part of a botnet.” November 27, 2025. https://x.com/BleepinComputer/status/1994061708487282919
- BleepingComputer News Tag. “Latest GreyNoise news.” Retrieved November 2025. https://www.bleepingcomputer.com/tag/greynoise/
