BlackShades Server

Hunt Hypothesis

This detection rule identifies the presence of the BlackShades Remote Access Trojan (RAT) server component, which adversaries deploy to establish persistent command-and-control channels for lateral movement and data exfiltration. Proactively hunting for this indicator within Azure Sentinel is critical because early identification of the RAT’s infrastructure allows the SOC team to isolate compromised endpoints before attackers can fully leverage its remote management capabilities.

YARA Rule

rule BlackShades2 : Trojan RAT
{
	meta:
		author="Kevin Falcoz"
		date="26/06/2013"
		description="BlackShades Server"
		
	strings:
		$signature1={62 73 73 5F 73 65 72 76 65 72}
		$signature2={43 4C 49 43 4B 5F 44 45 4C 41 59 00 53 43 4B 5F 49 44}
		$signature3={6D 6F 64 49 6E 6A 50 45}
		
	condition:
		$signature1 and $signature2 and $signature3
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 3 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 5 specific false positive scenarios for the BlackShades Server detection rule in an enterprise environment, along with recommended filters or exclusions:

• Antivirus Management Console Communication

  • Scenario: The BlackShades malware often communicates with a central command and control (C2) server. In many enterprises, legitimate Endpoint Detection and Response (EDR) agents like CrowdStrike Falcon, SentinelOne, or Microsoft Defender for Endpoint initiate similar persistent HTTPS connections to their respective cloud management consoles for policy updates and telemetry reporting.
  • Filter/Exclusion: Create an exclusion rule allowing traffic from the specific EDR agent service accounts (e.g., svc-crowdstrike, SentinelOneAgent) to known vendor IP ranges or fully qualified domain names (FQDNs) such as *.crowdstrike.com or *.sentinelone.net.

• Scheduled Patch Management Deployments

  • Scenario: Automated patch management tools frequently establish long-lived connections to software repositories during scheduled maintenance windows. Tools like Ivanti, ManageEngine Endpoint Central, or WSUS (Windows Server Update Services) may trigger the rule when they download large update packages or verify server health, mimicking the data exfiltration patterns of BlackShades.
  • Filter/Exclusion: Exclude traffic originating from the specific patch management service accounts during defined maintenance windows (e.g., 02:00 - 06:00 UTC) targeting known internal repository IPs or public vendor domains like *.microsoft.com and *.update.microsoft.com.

• Database Backup and Replication Jobs

  • Scenario: Enterprise database administrators often run scheduled backup jobs using tools like Veeam Backup & Replication, Commvault, or native SQL Server Agent jobs. These tasks generate high-volume, continuous network streams