ThreatFox: Unknown RAT IOCs

Hunt Hypothesis

This hypothesis posits that adversaries are deploying an unknown Remote Access Trojan (RAT) to establish persistent command-and-control channels within the network, as evidenced by three distinct indicators of compromise. Proactively hunting for these specific IOCs in Azure Sentinel is critical to identify early-stage lateral movement and data exfiltration attempts before they escalate into a full-blown incident.

IOC Summary

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

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - Unknown RAT
let malicious_urls = dynamic(["http://130.61.68.232:7317/api/screenshot", "http://130.61.68.232:7317/api/hvnc/register", "http://130.61.68.232:7317/api/hvnc/screenshot"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Unknown RAT

False Positive Guidance

Here are 4 specific false positive scenarios for the ThreatFox: Unknown RAT IOCs detection rule, tailored for an enterprise environment:

• Endpoint Management Agent Updates

  • Scenario: The deployment of a major version update for Microsoft Endpoint Configuration Manager (MECM/SCCM) or Ivanti Neurons. These agents often download and execute new telemetry modules that establish persistent network connections to internal management servers, mimicking the C2 beaconing behavior of a Remote Access Trojan.
  • Filter/Exclusion: Exclude processes originating from the C:\Program Files\Microsoft Configuration Manager or C:\Program Files (x86)\Ivanti directories where the parent process is ccmexec.exe or agent.exe. Additionally, whitelist the specific internal IP ranges of the management infrastructure.

• Scheduled Backup and Synchronization Jobs

  • Scenario: Execution of scheduled backup tasks using Veeam Agent for Windows or Acronis Cyber Protect. These tools frequently spawn worker processes that open multiple outbound connections to storage gateways and perform file integrity checks, generating network traffic patterns (periodic heartbeats and data bursts) identical to RAT activity.
  • Filter/Exclusion: Create a rule to ignore alerts where the process path contains Veeam or Acronis and the execution time aligns with defined maintenance windows (e.g., 02:00–04:00 UTC). Whitelist the specific destination ports used by these backup protocols (e.g., TCP 9396 for Veeam, UDP 873 for Acronis).

• Software Deployment and Patching Orchestrators

  • Scenario: Automated patching cycles driven by tools like Ansible, Chef, or SolarWinds Patch Manager. During a deployment window,