ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt detects adversary activity consistent with the DCRat remote access trojan by identifying specific indicators of compromise across network and endpoint telemetry within Azure Sentinel. Proactively hunting for these signatures is critical to rapidly identify early-stage lateral movement or command-and-control communications before they escalate into a full-blown data exfiltration incident.

IOC Summary

Malware Family: DCRat Total IOCs: 4 IOC Types: domain, url, ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["144.172.88.233"]);
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(["144.172.88.233"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - DCRat
let malicious_domains = dynamic(["nuevocomienzp333.duckdns.org", "gfhdsjkasd.duckdns.org"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - DCRat
let malicious_urls = dynamic(["https://store.julias.makeup/img_094957.png"]);
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 four specific false positive scenarios for the ThreatFox: DCRat IOCs detection rule in an enterprise environment, along with suggested filters or exclusions:

• Enterprise Antivirus Signature Updates via Scheduled Tasks

  • Scenario: The organization uses a centralized endpoint protection suite (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) that performs daily signature updates. These updates often involve downloading and executing specific DLLs or executables that may share hash values, file paths, or network connections with the DCRat IOCs. This is particularly common when the update mechanism runs as a scheduled task under the SYSTEM account during off-hours (e.g., 02:00 AM).
  • Suggested Filter: Exclude alerts where the process owner is NT AUTHORITY\SYSTEM and the parent process is the specific AV updater service (e.g., falcon.sys or MsMpEng.exe). Additionally, add a time-based exclusion to suppress alerts generated between 01:00 and 04:00 UTC.

• IT Asset Management & Patch Deployment Tools

  • Scenario: IT administrators utilize deployment tools like Microsoft SCCM (Configuration Manager) or Ivanti Endpoint Manager to push software patches across the fleet. During a mass deployment, these agents download and execute installation packages that may instantiate temporary files or network connections matching DCRat indicators. This often occurs when deploying updates to specific subnets containing legacy applications known to use similar communication protocols.
  • Suggested Filter: Create an exclusion for processes launched by the SCCM client (ccmexec.exe) or Ivanti agent, specifically filtering for events originating from the “IT Operations” Organizational Unit (OU) in Active Directory.

• Internal Development Build Pipelines

  • Scenario: The internal DevOps team utilizes Jenkins or