ThreatFox: DCRat IOCs

Hunt Hypothesis

This hypothesis posits that adversaries are deploying the DCRat remote access trojan within our Azure environment to establish persistent command-and-control channels and exfiltrate sensitive data. Proactive hunting for these specific IOCs is critical because early detection of DCRat activity allows the SOC team to isolate compromised endpoints before lateral movement occurs, thereby mitigating the high risk associated with this sophisticated threat actor.

IOC Summary

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

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["45.59.120.31"]);
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(["45.59.120.31"]);
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://cy614451.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 5 specific false positive scenarios for the ThreatFox: DCRat IOCs detection rule, tailored for an enterprise environment using the specified format:

• Legitimate Software Deployment via SCCM/Intune

  • Scenario: During a scheduled patching window, the System Center Configuration Manager (SCCM) or Microsoft Intune agent pushes a new software package to endpoints. The deployment executable triggers a network connection to a known DCRat C2 domain listed in the IOC set as part of its telemetry or update check mechanism.
  • Filter/Exclusion: Create an exclusion for source IP ranges belonging to the internal SCCM site server and Intune management gateway, specifically filtering out traffic where the Process Name matches ccmexec.exe or Microsoft.IntuneManagementExtension.exe.

• Antivirus Real-Time Scanning and Cloud Intelligence

  • Scenario: Enterprise Endpoint Detection and Response (EDR) agents such as CrowdStrike Falcon, SentinelOne, or Carbon Black perform real-time file scanning. Upon detecting a new file, the agent contacts its cloud intelligence service to fetch updated signatures, inadvertently connecting to an IP address that overlaps with DCRat IOCs.
  • Filter/Exclusion: Exclude traffic originating from known EDR service processes (e.g., csagent.exe, s1service.exe, cb.exe) and restrict the rule to only flag connections where the destination port is not standard for AV updates (e.g., exclude ports 443, 80 if the specific IOC uses non-standard ports).

• Scheduled Backup Jobs with External Cloud Storage

  • Scenario: A nightly scheduled task runs a backup utility like Veeam Agent or Acronis Cyber Backup. These tools upload incremental backups to an external cloud storage provider that happens to share a hosting infrastructure or IP block with the DCRat campaign