New! Attacker Exploited Citrix Zero-Day Three Days Before the CVE Existed
Claude gives security teams a conversational interface for investigating threats and analyzing complex security information. The GreyNoise MCP Server connects Claude directly to real-time threat context on malicious infrastructure, internet scanning, and vulnerability exploitation, helping analysts understand threat activity without leaving their workflow.
The GreyNoise MCP Server and pre-configured prompts operationalize four threat investigation use cases in Claude.
Most perimeter detection focuses on traffic coming in, while high outbound connection volumes make anomalous egress difficult to investigate. When an internal asset connects to known malicious infrastructure, it can indicate C2 beaconing, data exfiltration, or botnet participation.
Provide Claude with destination IPs from outbound firewall, proxy, and EDR telemetry. The GreyNoise MCP Server returns classification and observed activity for those IPs, enabling Claude to identify potentially compromised internal hosts that require immediate investigation or containment.
Authentication failures and brute-force attempts from the internet are constant for any perimeter device. The challenge is distinguishing opportunistic account access from attempts aimed specifically at your organization. Hosts conducting mass scanning or operating as part of botnet or proxy infrastructure regularly authenticate to VPNs and identity providers, and standard detection logic often does not flag it.
Ask Claude to evaluate source IPs from successful and failed authentication events using GreyNoise. The GreyNoise MCP Server returns classification and observed activity for those IPs, enabling Claude to flag successful logins from malicious infrastructure for immediate escalation and failed attempts that may indicate active targeting of your identity infrastructure.
Perimeter gaps often go unnoticed because allowed traffic is not validated after it passes through a firewall, WAF, or proxy. Without external threat intelligence, those connections may receive no further scrutiny, even when the source IP has a documented history of malicious activity.
Ask Claude to investigate source IPs from allowed firewall, WAF, or proxy connections using GreyNoise. The GreyNoise MCP Server returns classification, observed behavior, and activity history for those IPs, helping analysts identify allowed connections from malicious or suspicious infrastructure and determine whether the related perimeter control requires remediation.
The hardest part of perimeter monitoring is not finding activity. It is deciding what deserves attention. When routine internet traffic and potentially targeted behavior enter the same queue, analysts spend valuable time validating familiar patterns while urgent signals wait.
Ask Claude to analyze groups of source IPs from perimeter alerts using the GreyNoise MCP Server. Claude distinguishes known internet-wide scanning and common business services from malicious, suspicious, and previously unseen IPs, giving analysts a smaller, higher-signal set of events to investigate. Activity from IPs GreyNoise has never observed stands out as a stronger indicator of potential targeted reconnaissance or attack activity.
