ThreatFox: Mirai IOCs | SOC Hunt Feed

Hunt Hypothesis

This detection rule identifies network traffic matching three specific Indicators of Compromise (IOCs) linked to the Mirai botnet, which is known for launching large-scale DDoS attacks and compromising IoT devices. A proactive hunt in Azure Sentinel is critical because early identification of these IOCs allows the SOC team to isolate infected endpoints before they are recruited into a broader botnet network capable of disrupting enterprise services.

IOC Summary

Malware Family: Mirai Total IOCs: 3 IOC Types: sha256_hash, domain, url

Type	Value	Threat Type	First Seen	Confidence
sha256_hash	`35bf80f0af528d458d53a7f7179e0ae284d6fb2be613bab904b8fe115e730b0d`	payload	2026-08-13	80%
url	`hxxp://154[.]90[.]70[.]23/x86`	payload_delivery	2026-08-13	75%
domain	`kappadocia.net`	botnet_cc	2026-08-13	100%

KQL: Domain Hunt

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

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - Mirai
let malicious_urls = dynamic(["http://154.90.70.23/x86"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - Mirai
let malicious_hashes = dynamic(["35bf80f0af528d458d53a7f7179e0ae284d6fb2be613bab904b8fe115e730b0d"]);
DeviceFileEvents
| where SHA256 in (malicious_hashes) or SHA1 in (malicious_hashes) or MD5 in (malicious_hashes)
| project Timestamp, DeviceName, FileName, FolderPath, SHA256, InitiatingProcessFileName
| order by Timestamp desc

Required Data Sources

Sentinel Table	Notes
`DeviceFileEvents`	Ensure this data connector is enabled
`DnsEvents`	Ensure this data connector is enabled
`UrlClickEvents`	Ensure this data connector is enabled

References

ThreatFox — Mirai

False Positive Guidance

Here are specific false positive scenarios and corresponding filters for the ThreatFox: Mirai IOCs detection rule in an enterprise environment:

Scenario: Internal Vulnerability Scanning Traffic
- Context: Enterprise vulnerability scanners (e.g., Tenable Nessus, Qualys, or Rapid7 InsightVM) periodically probe IoT devices and network infrastructure. These scanners often generate traffic patterns that match Mirai’s signature behavior, such as specific UDP port scans on ports 23 (Telnet), 80 (HTTP), and 443 (HTTPS) from internal management subnets to a broad range of asset IPs.
- Filter/Exclusion: Create an exclusion rule based on the source IP ranges of the vulnerability scanner appliances or jump hosts. Additionally, filter out traffic where the destination port is restricted to known IoT device ports but the source belongs to the VULN_SCAN_NET subnet (e.g., 10.50.20.0/24).
Scenario: Scheduled Firmware Update Jobs
- Context: Automated patch management systems like Microsoft System Center Configuration Manager (SCCM) or Ivanti Neurons execute nightly firmware update jobs for network-attached storage (NAS), IP cameras, and smart printers. These devices often initiate outbound connections to vendor update servers that share the same public IP addresses or ASN ranges identified in the Mirai IOC list.
- Filter/Exclusion: Implement a time-based exclusion window during known maintenance windows (e.g., 02:00 - 06:00 UTC on weekdays). Furthermore, add an exclusion for specific destination domains associated with major IoT vendors (e.g., *.hikvision.com, *.axis.com) if the traffic originates from the IOT_MANAGEMENT VLAN.
**Scenario: Cloud Backup and Rep