ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt detects adversary activity involving the four specific indicators of compromise (IOCs) linked to the DCRat remote access trojan, which is frequently used by threat actors for initial foothold establishment and lateral movement within networks. A SOC team should proactively hunt for these IOCs in Azure Sentinel to identify early-stage infections that may evade standard signature-based detection, thereby enabling rapid containment before the adversary establishes persistent command-and-control channels or exfiltrates sensitive data.

IOC Summary

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

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["137.220.158.10", "160.202.241.103", "154.219.109.133"]);
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(["137.220.158.10", "160.202.241.103", "154.219.109.133"]);
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 specific false positive scenarios and corresponding filters for the ThreatFox: DCRat IOCs detection rule in an enterprise environment:

• Scenario: Scheduled Antivirus or EDR Scans

  • Context: Enterprise Endpoint Detection and Response (EDR) agents, such as CrowdStrike Falcon, Microsoft Defender for Endpoint, or Symantec Endpoint Protection, often initiate periodic deep scans. These tools may query external threat intelligence feeds or download signature updates that match DCRat IOCs (specifically file hashes or network destinations) used in the rule.
  • Filter/Exclusion: Create a process exclusion based on the EDR service executable name (e.g., C:\Program Files\CrowdStrike\csagent.exe or MsMpEng.exe) and exclude traffic originating from known internal update servers (e.g., WSUS or SCCM distribution points) that trigger these scans.

• Scenario: Legitimate Backup and Archiving Operations

  • Context: Automated backup solutions like Veeam Backup & Replication, Rubrik, or Commvault frequently generate large data transfers and create temporary archives. The DCRat rule may flag the specific file hashes of compressed backup containers (.vbk, .v2i) or the network ports used by these agents as suspicious if they overlap with known DCRat IOCs.
  • Filter/Exclusion: Exclude alerts where the parent process is a recognized backup service (e.g., Veeam.Backup.Service.exe or rubrik-agent) and filter out events occurring during defined maintenance windows (e.g., 02:00 – 06:00 local time) on dedicated backup subnets.

• Scenario: Admin-Driven Software Deployment via SCCM/Intune

  • Context: System Administrators using **