ThreatFox: Unknown RAT IOCs

Hunt Hypothesis

This hypothesis posits that adversaries are deploying an unknown Remote Access Trojan (RAT) by utilizing three specific Indicators of Compromise to establish persistent command-and-control channels within the network. Proactive hunting for these IOCs in Azure Sentinel is critical because early detection of this unidentified RAT can prevent lateral movement and data exfiltration before the threat matures into a full-scale incident.

IOC Summary

Malware Family: Unknown RAT Total IOCs: 3 IOC Types: domain

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Unknown RAT
let malicious_domains = dynamic(["survivaltraits.com", "mesh.sentra.cx", "sentrydb.org"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

References

• ThreatFox — Unknown RAT

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: Unknown RAT IOCs detection rule, tailored for an enterprise environment:

• Endpoint Management Software Deployment

  • Scenario: The deployment of a new agent or policy update by tools like Microsoft Intune, Ivanti Neurons, or SCCM. These agents often spawn multiple background processes and network connections to cloud endpoints that may not yet be in the ThreatFox IOC database, triggering alerts for “Unknown RAT” behavior due to their broad system access.
  • Suggested Filter: Exclude traffic originating from known management subnets (e.g., 10.20.50.0/24) or filter by specific process hashes associated with the EMM suite (e.g., DeviceManagementService.exe, IvantiAgent.exe).

• Automated Patching and Configuration Scripts

  • Scenario: Scheduled maintenance jobs running via Task Scheduler or Ansible Tower that execute PowerShell scripts to apply security patches. These scripts frequently establish outbound connections to software vendor repositories (e.g., Microsoft Update, Adobe) and create temporary files in C:\Windows\Temp or user profile directories, mimicking the file system and network activity of a Remote Access Trojan.
  • Suggested Filter: Create an exclusion for processes launched by the System account during defined maintenance windows (e.g., Sundays 02:00–04:00 UTC) and whitelist specific script paths such as C:\ProgramData\Ansible\scripts\.

• Third-Party Backup and Data Loss Prevention (DLP) Agents

  • Scenario: Background operations by enterprise backup solutions like Veeam Agent, Commvault, or DLP tools like Symantec DLP. These agents perform deep file scans, compress data, and upload to