ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt detects adversary behavior characterized by the execution of DCRat remote access trojan components, specifically targeting known indicators of compromise such as suspicious process launches and network connections to command-and-control infrastructure. Proactive hunting for these IOCs in Azure Sentinel is critical because DCRat’s stealthy nature allows attackers to establish persistent footholds that can evade standard signature-based defenses until significant data exfiltration occurs.

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(["141.94.121.162"]);
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(["141.94.121.162"]);
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, tailored for an enterprise environment:

• Endpoint Management Agent Updates

  • Scenario: The deployment of a new version of Microsoft Endpoint Configuration Manager (MECM/SCCM) or Ivanti Neurons triggers the download and execution of update packages. These agents often communicate with known software distribution servers that share IP ranges or hash signatures similar to DCRat’s command-and-control infrastructure, particularly when downloading large payload definitions.
  • Filter/Exclusion: Create a rule exclusion for processes originating from C:\Program Files\Microsoft Configuration Manager\ (or the specific vendor path) and network destinations matching the internal IP ranges of your Software Distribution Servers (e.g., 10.x.x.x).

• Scheduled Antivirus Definition Refreshes

  • Scenario: A scheduled task running via Windows Task Scheduler executes a script to fetch the latest virus definition updates for CrowdStrike Falcon, SentinelOne, or Trend Micro. These security tools frequently utilize cloud-based update servers that may generate network traffic patterns (specifically HTTP/HTTPS connections to specific ports) matching the DCRat IOCs, especially during off-hours maintenance windows.
  • Filter/Exclusion: Exclude alerts where the parent process is TaskScheduler.exe and the child process matches known EDR service executables (e.g., C:\Program Files\CrowdStrike\fsagent.exe). Additionally, filter out traffic occurring strictly between 02:00 and 04:00 UTC if updates are scheduled during this window.

• Third-Party Patch Management Execution

  • Scenario: The execution of Patch My PC, ManageEngine Endpoint Central, or SolarWinds Patch Manager initiates a background job to scan for