ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt detects adversary activity involving the DCRat remote access trojan by identifying specific indicators of compromise such as malicious network connections and file artifacts. Proactively hunting for these signals in Azure Sentinel is critical to rapidly identify early-stage lateral movement or command-and-control communications before they escalate into a full-scale data breach.

IOC Summary

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

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["64.89.161.196", "78.17.213.180"]);
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(["64.89.161.196", "78.17.213.180"]);
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 and corresponding filters for the ThreatFox: DCRat IOCs detection rule in an enterprise environment:

• Legitimate Endpoint Management Scans

  • Scenario: Enterprise endpoint protection suites (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint) or vulnerability scanners (e.g., Tenable Nessus) periodically download and execute signature definition updates. These processes often generate network traffic or file hashes that match the DCRat IOCs due to shared cryptographic signatures or similar payload structures in the update bundles.
  • Filter/Exclusion: Exclude process paths belonging to known security agents (e.g., C:\Program Files\CrowdStrike\FalconSensor\csfalcon.exe or C:\ProgramData\Microsoft\Windows Defender\platform\mpcmdrun.exe) and filter out network connections originating from the specific IP ranges of internal update servers.

• Scheduled Backup and Data Archiving Jobs

  • Scenario: Automated backup solutions (e.g., Veeam, Commvault) or data archiving scripts running via Windows Task Scheduler often utilize compression algorithms that produce file hashes identical to those flagged by the DCRat rule. This is common when backing up large datasets containing embedded certificates or encrypted blobs similar to the malware’s structure.
  • Filter/Exclusion: Create an exclusion for scheduled tasks named with prefixes like VeeamBackup or CommvaultAgent, and filter out file creation events where the parent process is a known backup service (e.g., vbrsvc.exe) running during defined maintenance windows (e.g., 02:00–04:00 local time).

• Software Deployment via Configuration Management Tools

  • Scenario: IT administrators using tools like Microsoft Endpoint Configuration Manager (MECM/SCCM) or Ansible to deploy new applications may trigger the rule when