ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt detects adversary activity involving the DCRat remote access tool by monitoring for specific indicators of compromise such as unique file hashes and network connections. A SOC team should proactively search for these signals in Azure Sentinel to identify early-stage lateral movement or command-and-control communications that may indicate a stealthy post-exploitation presence.

IOC Summary

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

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["91.202.233.120"]);
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(["91.202.233.120"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - DCRat
let malicious_urls = dynamic(["http://dsfdsfs.xsph.ru/L1nc0In.php", "http://ce557109.tw1.ru/L1nc0In.php"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — DCRat

False Positive Guidance

Here are 4 specific false positive scenarios for the ThreatFox: DCRat IOCs detection rule, including suggested filters and exclusions tailored for an enterprise environment:

• Scenario: Automated Endpoint Protection Scans

  • Context: Enterprise EDR agents (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) frequently download definition updates or perform scheduled deep scans that match DCRat network signatures. These legitimate processes often initiate outbound connections to vendor update servers using ports and protocols similar to the malware’s command-and-control traffic.
  • Suggested Filter/Exclusion: Exclude processes where the executable name matches known EDR agents (e.g., FalconSensor.exe, MsMpEng.exe) AND the destination IP belongs to the vendor’s trusted CIDR block (e.g., 13.0.0.0/8 for Microsoft or 64.205.0.0/16 for CrowdStrike).

• Scenario: Scheduled Backup and Replication Jobs

  • Context: Enterprise backup solutions like Veeam, Rubrik, or Commvault often run scheduled jobs during off-hours that establish persistent connections to cloud storage buckets (AWS S3, Azure Blob) or on-premise repositories. The traffic patterns of these replication streams can mimic the data exfiltration behavior flagged by DCRat IOCs.
  • Suggested Filter/Exclusion: Create an exclusion for processes running under specific service accounts (e.g., DOMAIN\BackupSvc) where the destination port is standard storage ports (9443, 8080) and the traffic volume exceeds a threshold typical of malware beacons but aligns with backup job windows.

• Scenario: Software Deployment via Configuration Management

  • Context: IT administrators using tools like SCCM (Microsoft Endpoint Manager), Ansible, or Puppet frequently push