DestructiveHardDriveTool1

Hunt Hypothesis

This detection identifies adversaries utilizing destructive hard drive tools to intentionally erase or corrupt storage media, a tactic often employed during data exfiltration cover-ups or post-compromise cleanup phases. Proactively hunting for this behavior in Azure Sentinel is critical because low-severity alerts may indicate early-stage infrastructure sabotage that could escalate into significant operational downtime if not correlated with other suspicious activities before full system failure occurs.

YARA Rule

rule DestructiveHardDriveTool1
{
	strings:
		$str0= "MZ"
		$str1 = {c6 84 24 ?? ( 00 | 01 ) 00 00 }
		$xorInLoop = { 83 EC 20 B9 08 00 00 00 33 D2 56 8B 74 24 30 57 8D 7C 24 08 F3 A5 8B 7C 24 30 85 FF 7E 3A 8B 74 24 2C 8A 44 24 08 53 8A 4C 24 21 8A 5C 24 2B 32 C1 8A 0C 32 32 C3 32 C8 88 0C 32 B9 1E 00 00 00 8A 5C 0C 0C 88 5C 0C 0D 49 83 F9 FF 7F F2 42 88 44 24 0C 3B D7 7C D0 5B 5F 5E 83 C4 20 C3 }
	
	condition:
		$str0 at 0 and $xorInLoop and #str1 > 300
}

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 DestructiveHardDriveTool1 detection rule, tailored for an enterprise environment:

• Scheduled Data Sanitization by IT Operations

  • Scenario: The IT Operations team runs a weekly scheduled task on decommissioned workstations to securely wipe local drives before repurposing. This involves the execution of DBAN (Darik's Boot and Nuke) or Parted Magic utilities, which trigger the rule due to their aggressive overwrite patterns.
  • Filter/Exclusion: Create an exclusion for the specific executable hash of the sanitization tool (dban.exe) running from a known management server IP range during the maintenance window (e.g., Sundays 02:00–04:00 UTC).

• Endpoint Protection Agent Self-Healing

  • Scenario: The enterprise endpoint protection suite (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) performs a “Self-Heal” operation where it rewrites corrupted system partitions or clears the pagefile to resolve disk errors. This activity mimics destructive drive tools by accessing low-level disk sectors.
  • Filter/Exclusion: Exclude processes with the parent process name MsMpEng.exe (Defender) or csfalcon.exe (CrowdStrike) when they invoke child processes related to disk management, specifically filtering out events where the command line contains flags like /repair or /clean.

• Software Deployment via Configuration Management

  • Scenario: During a major OS upgrade cycle, the Ansible or SCCM (System Center Configuration Manager) deployment engine executes scripts that reformat temporary installation drives on thousands of endpoints simultaneously. The diskpart utility is frequently called within these scripts to partition and format local SSDs before installing new images.

  ---