Disclosed hacktool set - file Start.bat - DoS tool

Hunt Hypothesis

This detection identifies adversaries deploying a batch script named “Start.bat” to execute Denial of Service (DoS) tools, which often serve as an initial foothold for disrupting critical services or masking subsequent malicious activities. SOC teams should proactively hunt for this behavior in Azure Sentinel because the use of common batch files like Start.bat is a prevalent evasion tactic that can easily bypass standard signature-based defenses while enabling rapid impact on system availability.

YARA Rule

rule Hacktools_CN_Burst_Start {
	meta:
		description = "Disclosed hacktool set - file Start.bat - DoS tool"
		author = "Florian Roth"
		date = "17.11.14"
		score = 60
		hash = "75d194d53ccc37a68286d246f2a84af6b070e30c"
	strings:
		$s0 = "for /f \"eol= tokens=1,2 delims= \" %%i in (ip.txt) do (" fullword ascii
		$s1 = "Blast.bat /r 600" fullword ascii
		$s2 = "Blast.bat /l Blast.bat" fullword ascii
		$s3 = "Blast.bat /c 600" fullword ascii
		$s4 = "start Clear.bat" fullword ascii
		$s5 = "del Result.txt" fullword ascii
		$s6 = "s syn %%i %%j 3306 /save" fullword ascii
		$s7 = "start Thecard.bat" fullword ascii
		$s10 = "setlocal enabledelayedexpansion" fullword ascii
	condition:
		5 of them
}

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 9 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 5 specific false positive scenarios for the Disclosed hacktool set - file Start.bat - DoS tool detection rule, along with targeted exclusion strategies:

• Scenario: Automated Patch Deployment via SCCM/Intune

  • Context: System Center Configuration Manager (SCCM) or Microsoft Intune often deploys a Start.bat script to client machines to orchestrate the installation of security patches or software updates. This batch file may invoke network diagnostic tools that mimic DoS behavior by sending high-volume pings or connection checks during the deployment window.
  • Filter/Exclusion: Exclude processes where the parent process is ccmexec.exe (SCCM) or Microsoft.IntuneManagementService.exe, and the file path contains \CCM\ or \IntuneAgent\.

• Scenario: Scheduled Network Health Monitoring Job

  • Context: A nightly scheduled task runs a custom network health check using tools like WinPing, Nmap, or MTR wrapped in a Start.bat wrapper. This job actively scans subnets and ports, generating traffic patterns that the rule interprets as a potential DoS tool execution.
  • Filter/Exclusion: Create an exclusion for Start.bat files located in specific administrative directories (e.g., C:\ProgramData\NetworkOps\Scripts\) running under a dedicated service account like svc_network_monitor.

• Scenario: Endpoint Protection Quarantine & Remediation

  • Context: Enterprise EDR solutions (such as CrowdStrike Falcon, SentinelOne, or Carbon Black) often utilize internal batch scripts to isolate files or initiate remediation workflows. When the EDR agent executes a Start.bat script to launch a local DoS mitigation utility for a specific threat signature, it triggers this rule.
  • Filter/Exclusion: Exclude any