ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt detects adversary activity involving the DCRat remote administration tool by identifying matches against a specific set of twelve known indicators of compromise within Azure Sentinel logs. Proactively hunting for these IOCs is critical to rapidly identify and contain potential command-and-control communications or lateral movement attempts before they escalate into broader network incidents.

IOC Summary

Malware Family: DCRat Total IOCs: 12 IOC Types: sha1_hash, md5_hash, sha256_hash

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - DCRat
let malicious_hashes = dynamic(["fd669e1388907d25b8039b5ae22804a6b77a96d139c8f8bbff50c15c9968bfa2", "55888979b9436e79d41aeb0b763de01ed99b85db", "1bd88bbb0c82349303aa60c470c8b51e", "1fa24618993a4828e566da20b40bb181", "50ab6fa03c74aac498627a9949d88931f4b15fd8", "f92d8a2f5c3d9140c233c0012d9ad43e", "c6d374bf20c20fd3a1b14a1e8a8334c41cdf9c3098bc2f8b1afbec7ac43881af", "82454d9f0d4b22bc8357285e8397ee3a", "36cd6bffbae0e88e20b56251445092e57977a990ea2f92e84321ecc9a16eb53b", "bc716d57de7f312667adfb4831c6ee419d23c1a9", "9c19c3b393c667beccc02574abdeb3e5b4793bb49550daadeab78af2e45cc97f", "f8a6f532ba303705606a91a2416e09e8f4cc7263"]);
DeviceFileEvents
| where SHA256 in (malicious_hashes) or SHA1 in (malicious_hashes) or MD5 in (malicious_hashes)
| project Timestamp, DeviceName, FileName, FolderPath, SHA256, InitiatingProcessFileName
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — DCRat

False Positive Guidance

Here are 4 specific false positive scenarios and corresponding exclusion strategies for the ThreatFox: DCRat IOCs detection rule in an enterprise environment:

• Scenario: Automated Backup Job Execution

  • Context: Enterprise backup solutions like Veeam Backup & Replication or Commvault often utilize PowerShell scripts or custom agents that generate network traffic and file hashes matching the DCRat IOCs (specifically regarding DLL injection patterns or specific registry keys used for persistence). These jobs run nightly via Windows Task Scheduler.
  • Filter/Exclusion: Create an exclusion rule based on the Process Name (Veeam.Backup.Service.exe or commvault.cmd) and the User Account (e.g., DOMAIN\BackupServiceAccount). Exclude alerts where the parent process is a known backup service running under a dedicated service account.

• Scenario: Endpoint Detection & Response (EDR) Self-Protection Scans

  • Context: The organization’s EDR agent, such as CrowdStrike Falcon, SentinelOne, or Microsoft Defender for Endpoint, performs periodic self-scans and updates. These agents often inject code into system processes to monitor behavior, which can trigger the DCRat IOCs related to process hollowing or specific network connections to update servers that overlap with DCRat’s C2 infrastructure.
  • Filter/Exclusion: Exclude alerts where the Parent Process belongs to the EDR suite (e.g., C:\Program Files\CrowdStrike\Falcon Sensor\csfalcon.exe) and the Network Destination IP falls within the vendor’s known update ranges (e.g., CrowdStrike CDN IPs).

• Scenario: Scheduled PowerShell Administrative Tasks

  • Context: IT Operations teams utilize scheduled tasks to run administrative scripts for user provisioning or patch management using PowerShell. These