ThreatFox: DCRat IOCs

Hunt Hypothesis

This hunt targets adversary activity involving known DCRat remote access trojan indicators to identify compromised endpoints exhibiting suspicious network connections or process executions linked to this malware family. Proactively hunting for these IOCs in Azure Sentinel is critical because early detection of DCRat infections allows the SOC team to rapidly isolate affected systems and prevent potential lateral movement before attackers establish persistent command-and-control channels.

IOC Summary

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

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - DCRat
let malicious_ips = dynamic(["91.219.238.166"]);
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(["91.219.238.166"]);
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://cc602316.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

False Positive Scenarios: ThreatFox: DCRat IOCs

• Scenario: Legitimate internal patch management deployment where the Microsoft Endpoint Configuration Manager (SCCM) or Intune pushes a security update containing a DCRat-related DLL or executable hash. The detection logic flags this as a new threat because the specific file hash is present in the enterprise but not yet whitelisted in the ThreatFox feed.

  • Suggested Filter/Exclusion: Create an exclusion rule based on the Source Process Name (e.g., ccmsetup.exe, IntuneManagementExtension.exe) and the Installation Path. If the file is located within the standard software distribution directories (e.g., C:\Program Files\Microsoft Configuration Manager), suppress the alert.

• Scenario: A scheduled nightly backup job executed by Veeam Backup & Replication or Commvault scans a directory containing legacy applications that utilize DCRat-compatible libraries. The backup agent generates network traffic and file access events matching the DCRat IOCs, triggering a false positive due to high-volume file I/O.

  • Suggested Filter/Exclusion: Implement a time-based exclusion for the specific host group running these jobs (e.g., Backup-Server-Group). Additionally, filter out alerts where the Parent Process is identified as vrb.exe or cmdagent.exe, ensuring that backup-related IOCs do not trigger the rule during maintenance windows.

• Scenario: The IT Operations team deploys a new version of an internal line-of-business (LOB) application using Ansible automation scripts. This application includes a custom module that mimics DCRat behavior for remote command execution, causing the detection engine to flag the IOCs as malicious due to the presence of specific registry keys or network connections associated with DCRat.

  • **Suggested Filter/