ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt targets adversary behavior involving the execution of DCRat remote access tools by correlating three specific indicators of compromise within Azure Sentinel logs. Proactively hunting for these signatures is critical to detect early-stage command-and-control communications and prevent potential data exfiltration before they escalate into a full-blown incident.

IOC Summary

Malware Family: DCRat Total IOCs: 3 IOC Types: ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["128.90.105.247", "196.251.121.74", "176.53.159.46"]);
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(["128.90.105.247", "196.251.121.74", "176.53.159.46"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — DCRat

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: DCRat IOCs detection rule, along with suggested filters to mitigate noise in an enterprise environment:

• Legitimate Remote Administration via RDP or VNC Tools

  • Scenario: Administrators frequently use tools like Microsoft Remote Desktop (mstsc.exe), TeamViewer, or AnyDesk to manage remote servers. These applications often spawn child processes that establish outbound connections to known IP ranges used by DCRat’s legitimate infrastructure (e.g., for license validation or update checks), triggering the “DCRat IOCs” network or process creation alerts.
  • Suggested Filter: Exclude events where the parent process is a known remote administration tool (mstsc.exe, teamviewer_service.exe, AnyDeskService.exe) and the destination IP belongs to the organization’s approved management subnet or the vendor’s official update servers (verified via WHOIS lookup).

• Scheduled Software Deployment and Patch Management Jobs

  • Scenario: Enterprise patching solutions like Microsoft Endpoint Configuration Manager (MECM/SCCM), Ivanti, or Jamf run scheduled tasks during maintenance windows. These jobs often download payloads from internal repositories that share IP addresses with DCRat’s cloud infrastructure, causing the detection logic to flag these routine downloads as suspicious IOCs associated with the DCRat threat family.
  • Suggested Filter: Create a time-based exclusion for events occurring within defined maintenance windows (e.g., 02:00–04:00 UTC) and filter out traffic originating from specific service accounts used by deployment tools (e.g., NT AUTHORITY\SYSTEM, svc-sccm-agent) communicating with the internal software distribution point IPs.

• Third-Party Security Agent Communication

  • Scenario: Endpoint Detection and Response (EDR) agents