BlackShades RAT

Hunt Hypothesis

This detection rule identifies the presence of BlackShades Remote Access Trojan (RAT), which adversaries deploy to establish persistent command-and-control channels and exfiltrate sensitive data from compromised endpoints. Proactively hunting for this specific malware in Azure Sentinel is critical because its low-severity classification may cause it to be overlooked by automated alerts, necessitating manual investigation to confirm early-stage infection before lateral expansion occurs.

YARA Rule

rule BlackShades_3 : Trojan RAT
{
    meta:
        description = "BlackShades RAT"
	author = "botherder https://github.com/botherder"

    strings:
        $mod1 = /(m)odAPI/
        $mod2 = /(m)odAudio/
        $mod3 = /(m)odBtKiller/
        $mod4 = /(m)odCrypt/
        $mod5 = /(m)odFuctions/
        $mod6 = /(m)odHijack/
        $mod7 = /(m)odICallBack/
        $mod8 = /(m)odIInet/
        $mod9 = /(m)odInfect/
        $mod10 = /(m)odInjPE/
        $mod11 = /(m)odLaunchWeb/
        $mod12 = /(m)odOS/
        $mod13 = /(m)odPWs/
        $mod14 = /(m)odRegistry/
        $mod15 = /(m)odScreencap/
        $mod16 = /(m)odSniff/
        $mod17 = /(m)odSocketMaster/
        $mod18 = /(m)odSpread/
        $mod19 = /(m)odSqueezer/
        $mod20 = /(m)odSS/
        $mod21 = /(m)odTorrentSeed/

        $tmr1 = /(t)mrAlarms/
        $tmr2 = /(t)mrAlive/
        $tmr3 = /(t)mrAnslut/
        $tmr4 = /(t)mrAudio/
        $tmr5 = /(t)mrBlink/
        $tmr6 = /(t)mrCheck/
        $tmr7 = /(t)mrCountdown/
        $tmr8 = /(t)mrCrazy/
        $tmr9 = /(t)mrDOS/
        $tmr10 = /(t)mrDoWork/
        $tmr11 = /(t)mrFocus/
        $tmr12 = /(t)mrGrabber/
        $tmr13 = /(t)mrInaktivitet/
        $tmr14 = /(t)mrInfoTO/
        $tmr15 = /(t)mrIntervalUpdate/
        $tmr16 = /(t)mrLiveLogger/
        $tmr17 = /(t)mrPersistant/
        $tmr18 = /(t)mrScreenshot/
        $tmr19 = /(t)mrSpara/
        $tmr20 = /(t)mrSprid/
        $tmr21 = /(t)mrTCP/
        $tmr22 = /(t)mrUDP/
        $tmr23 = /(t)mrWebHide/

    condition:    
        10 of ($mod*) or 10 of ($tmr*)
}

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 44 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 3-5 specific false positive scenarios for the BlackShades RAT detection rule in an enterprise environment, along with suggested filters or exclusions:

• Legitimate Remote Administration via RDP/SSH Scripts

  • Scenario: System administrators frequently use PowerShell scripts or Bash automation to manage remote sessions. These scripts often spawn powershell.exe or bash processes that inject code into the memory of the target session (similar to how BlackShades operates) and establish persistent connections using standard ports (3389, 22). The detection logic may misinterpret these legitimate injection patterns as the RAT’s payload delivery mechanism.
  • Suggested Filter: Exclude processes where the parent process is a known administrative tool (e.g., Task Scheduler, System Center Configuration Manager, or specific CI/CD agents like Jenkins Agent) and the command line contains standard flags for remote execution (e.g., -EncodedCommand in PowerShell). Additionally, whitelist traffic originating from the internal “Admin VLAN” IP range.

• Endpoint Detection and Response (EDR) Self-Protection & Scanning

  • Scenario: Enterprise EDR solutions such as CrowdStrike Falcon, Microsoft Defender for Endpoint, or SentinelOne perform deep memory scanning and heuristic analysis. These tools often inject DLLs into running processes to monitor behavior, which mimics the “code injection” signature of BlackShades RAT. Furthermore, scheduled full-system scans may trigger high-volume network beaconing that resembles the RAT’s command-and-control (C2) heartbeat.
  • Suggested Filter: Create an exclusion rule for any process where the Image Path matches known EDR service executables (e.g., C:\Program Files\CrowdStrike\fs.exe, C:\ProgramData\Microsoft\Windows Defender\Platform\*). Also, filter out network connections where