ThreatFox: Mirai IOCs | SOC Hunt Feed

Hunt Hypothesis

This hunt targets adversary behavior where Mirai malware scans networks to identify IoT devices with default credentials or weak configurations for initial compromise and subsequent botnet recruitment. Proactively hunting for these indicators in Azure Sentinel is critical to detect early-stage infections before they scale into large-scale DDoS attacks that could overwhelm organizational resources.

IOC Summary

Malware Family: Mirai Total IOCs: 4 IOC Types: ip:port, domain

Type	Value	Threat Type	First Seen	Confidence
ip:port	`162[.]249[.]125[.]140:4569`	payload_delivery	2026-07-20	100%
ip:port	`162[.]249[.]125[.]140:4568`	payload_delivery	2026-07-20	100%
ip:port	`162[.]249[.]125[.]140:9018`	payload_delivery	2026-07-20	100%
domain	`nvms9000.online`	payload_delivery	2026-07-20	100%

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Mirai
let malicious_ips = dynamic(["162.249.125.140"]);
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(["162.249.125.140"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Mirai
let malicious_domains = dynamic(["nvms9000.online"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

Sentinel Table	Notes
`CommonSecurityLog`	Ensure this data connector is enabled
`DeviceNetworkEvents`	Ensure this data connector is enabled
`DnsEvents`	Ensure this data connector is enabled

References

ThreatFox — Mirai

False Positive Guidance

Here are 4 specific false positive scenarios for the ThreatFox: Mirai IOCs detection rule in an enterprise environment, along with recommended filters or exclusions:

Automated Firmware Update Scans by IT Management Tools
- Scenario: Enterprise asset management tools like SolarWinds NPM, ** Lansweeper**, or ManageEngine OpManager perform scheduled daily scans to check IoT device firmware versions and open ports. These tools often initiate TCP connections (specifically on ports 23, 80, and 8080) from a centralized management server to thousands of IP cameras, printers, and smart thermostats. The detection logic may misinterpret these high-volume, sequential connection attempts as Mirai’s initial network scanning phase.
- Filter/Exclusion: Create an exclusion rule for source IPs belonging to the Asset Management Subnet (e.g., 10.20.50.0/24) when connecting to destination ports 23, 80, and 8080. Additionally, exclude traffic where the User-Agent string contains specific identifiers like “SolarWinds-Scanner” or “Lansweeper-Agents”.
Scheduled Network Inventory Jobs via Scripted Tasks
- Scenario: System administrators often run custom PowerShell or Python scripts (e.g., Check-IoTHealth.ps1) on a dedicated jump server to inventory network devices. These jobs iterate through IP ranges, attempting to connect to default ports to verify device availability and configuration status. Because Mirai relies heavily on scanning for open ports 23 (Telnet) and 80 (HTTP), these legitimate administrative scripts generate traffic patterns that mimic the malware’s reconnaissance behavior.
- Filter/Exclusion: Exclude source IPs assigned to Jump Hosts or Script Execution Servers. Furthermore, implement a time