ThreatFox: N-W0rm IOCs

Hunt Hypothesis

This hunt targets adversary activity involving specific Indicators of Compromise (IOCs) linked to the N-W0rm malware, which is known for its rapid propagation and data exfiltration capabilities across networked systems. Proactively hunting for these signatures in Azure Sentinel is critical because early detection allows the SOC team to isolate infected endpoints before lateral movement occurs, thereby minimizing potential data loss and operational disruption.

IOC Summary

Malware Family: N-W0rm Total IOCs: 2 IOC Types: ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - N-W0rm
let malicious_ips = dynamic(["178.66.70.14", "188.32.41.18"]);
CommonSecurityLog
| where DestinationIP in (malicious_ips) or SourceIP in (malicious_ips)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, DeviceAction, Activity
| order by TimeGenerated desc

KQL: Ip Hunt Device

// Hunt in Defender for Endpoint network events
let malicious_ips = dynamic(["178.66.70.14", "188.32.41.18"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — N-W0rm

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: N-W0rm IOCs detection rule in an enterprise environment, along with recommended filters or exclusions:

• Antivirus Engine Updates and Scans

  • Scenario: Enterprise Endpoint Detection and Response (EDR) agents like CrowdStrike Falcon, Microsoft Defender for Endpoint, or Symantec Endpoint Protection frequently download and execute signature updates. The N-W0rm IOCs may include specific hash values or file paths that overlap with legitimate update executables (e.g., mssec.exe or symantec_antivirus_update.exe) running during scheduled maintenance windows.
  • Filter/Exclusion: Create an exclusion for the specific process names and parent processes associated with your AV vendor’s updater service. Additionally, filter out alerts originating from the “System” account (NT AUTHORITY\SYSTEM) or the specific Service Account used by the AV management console during known maintenance hours (e.g., 02:00–04:00 AM).

• Patch Management and Software Deployment

  • Scenario: Automated patching tools such as Microsoft SCCM (Configuration Manager), Ivanti, or Jamf Pro distribute software updates across the network. N-W0rm IOCs might match temporary installer files, script runners (powershell.exe), or deployment agents that execute on workstations during the “Patch Tuesday” cycle. These legitimate deployments often trigger file creation and execution events matching the worm’s behavioral profile.
  • Filter/Exclusion: Exclude alerts where the parent process is identified as a known patch management agent (e.g., ccmexec.exe, jamfagentd). Implement a rule to suppress detections if the source IP belongs to the internal Software Distribution Server subnet and the event timestamp aligns with the organization’s scheduled deployment window.

• **Scheduled