ThreatFox: Tsundere IOCs

Hunt Hypothesis

This hunt detects adversary activity associated with the Tsundere threat actor by monitoring for specific Indicators of Compromise (IOCs) that signal potential initial access or command-and-control communications. A SOC team should proactively hunt for these signals in Azure Sentinel to rapidly identify and contain early-stage intrusions, leveraging high-severity alerts to mitigate risks before lateral movement occurs.

IOC Summary

Malware Family: Tsundere Total IOCs: 2 IOC Types: ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Tsundere
let malicious_ips = dynamic(["2.27.248.234", "2.27.160.24"]);
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(["2.27.248.234", "2.27.160.24"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Tsundere

False Positive Guidance

Here are 5 specific false positive scenarios for the ThreatFox: Tsundere IOCs detection rule, including suggested filters and exclusions tailored for an enterprise environment:

• Scenario: Automated Patch Management Scans

  • Context: Enterprise patch management tools (e.g., Microsoft SCCM, Ivanti Neurons, or SolarWinds Patch Manager) frequently scan endpoints to identify missing updates. These agents often query external threat intelligence feeds that may share IP ranges or hash signatures with the Tsundere campaign, triggering a hit on standard update manifests.
  • Filter/Exclusion: Exclude network traffic and file hashes originating from known patch management servers (e.g., Source_IP in range 10.20.50.0/24) or filter out events where the process name matches ccmsetup.exe, IvantiAgent.exe, or SolarWindsPatch.exe.

• Scenario: Scheduled Cloud Backup Agent Operations

  • Context: Cloud backup solutions (e.g., Veeam, Rubrik, or Acronis Cyber Protect) perform scheduled jobs that download large metadata files and configuration manifests from the cloud. If Tsundere IOCs include specific file hashes used in these manifest structures, the detection logic will flag legitimate backup synchronization as a potential threat.
  • Filter/Exclusion: Create an exclusion rule for processes running under the SYSTEM account during defined maintenance windows (e.g., 02:00–04:00 local time) where the process executable path contains \Program Files\BackupAgent\.

• Scenario: Endpoint Detection and Response (EDR) Telemetry Uploads

  • Context: EDR agents like CrowdStrike Falcon, SentinelOne, or Carbon Black continuously upload telemetry data to their cloud consoles