T1006 Direct Volume Access

T1006 Direct Volume Access

High-Level Description

Adversaries may directly access a volume to bypass file access controls and file system monitoring. Windows allows programs to have direct access to logical volumes. Programs with direct access may read and write files directly from the drive by analyzing file system data structures. This technique may bypass Windows file access controls as well as file system monitoring tools.

Utilities, such as NinjaCopy, exist to perform these actions in PowerShell. Adversaries may also use built-in or third-party utilities (such as vssadmin, wbadmin, and esentutl) to create shadow copies or backups of data from system volumes.

Kill Chain Phase

• Defense Evasion (TA0005)

Platforms: Network Devices, Windows

What to Check

• Identify if Direct Volume Access technique is applicable to target environment
• Check Network Devices systems for indicators of Direct Volume Access
• Check Windows systems for indicators of Direct Volume Access
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: Read volume boot sector via DOS device path (PowerShell)

This test uses PowerShell to open a handle on the drive volume via the \\.\ DOS device path specifier and perform direct access read of the first few bytes of the volume. On success, a hex dump of the first 11 bytes of the volume is displayed.

For a NTFS volume, it should correspond to the following sequence (NTFS partition boot sector):

           00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000   EB 52 90 4E 54 46 53 20 20 20 20                 ëR?NTFS