Detect Direct Volume Access in Elastic Security
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, enabling reads and writes directly from the drive by analyzing file system data structures. This technique bypasses Windows file access controls and file system monitoring tools. Utilities such as NinjaCopy (PowerShell), vssadmin, wbadmin, and esentutl can be used to create shadow copies or access locked files (such as ntds.dit, SYSTEM hive, and SAM) directly from disk. Real-world actors including Scattered Spider and Volt Typhoon have leveraged Volume Shadow Copy Service (VSS) to extract credential stores without triggering standard file access controls.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1006 Direct Volume Access
- Canonical reference
- https://attack.mitre.org/techniques/T1006/
Elastic Detection Query
any where
(
event.category == "process" and event.type == "start" and
(
(
process.name in~ ("vssadmin.exe", "esentutl.exe", "diskshadow.exe", "ntdsutil.exe", "wbadmin.exe") and
process.command_line like~ ("*create shadow*", "*list shadow*", "*delete shadow*",
"*HarddiskVolumeShadowCopy*", "*GLOBALROOT*", "*ifm*", "*activate instance*",
"*start backup*", "*start recovery*", "*/y *", "*/vss*")
) or
(
process.name in~ ("powershell.exe", "pwsh.exe") and
process.command_line like~ ("*NinjaCopy*", "*Invoke-NinjaCopy*", "*PhysicalDrive*",
"*HarddiskVolumeShadowCopy*", "*GLOBALROOT*", "*GetDriveGeometry*",
"*FSCTL_GET_NTFS_VOLUME_DATA*", "*DeviceIoControl*")
) or
(
process.command_line like~ ("*PhysicalDrive*", "*HarddiskVolumeShadowCopy*", "*HarddiskVolume*") and
not process.name in~ ("vssvc.exe", "svchost.exe", "wmiprvse.exe")
)
)
) or
(
event.category == "file" and
file.path like~ ("*HarddiskVolumeShadowCopy*", "*GLOBALROOT*") and
file.name in~ ("ntds.dit", "ntds.jfm", "sam", "security", "system", "ntuser.dat", "security.bak")
)Detects T1006 Direct Volume Access using Elastic ECS process and file events. Four branches: (1) VSS management tool abuse via vssadmin, esentutl, diskshadow, ntdsutil, wbadmin with suspicious arguments; (2) PowerShell-based raw disk access including NinjaCopy and low-level volume APIs; (3) direct volume path strings in any non-system process command line; (4) file access events reading credential store files from shadow copy paths.
Data Sources
Required Tables
False Positives & Tuning
- Enterprise backup software (Veeam, Acronis, Windows Server Backup, Azure Backup agent) that invokes vssadmin.exe or wbadmin.exe on scheduled backup jobs — particularly noisy on dedicated backup servers and domain controllers with regular snapshot schedules
- IT administrators performing authorized Active Directory maintenance using ntdsutil.exe with IFM arguments for domain controller promotion media creation, or esentutl.exe for offline NTDS defragmentation
- Endpoint detection and response platforms or forensic tools that enumerate shadow copies, scan VSS snapshots for malware, or perform integrity checks using raw volume access as part of their normal sensor activity
Other platforms for T1006
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1VSS Shadow Copy Creation and NTDS Extraction via esentutl
Expected signal: Sysmon Event ID 1: Process Create for vssadmin.exe with CommandLine containing 'create shadow /for=C:'. Second Sysmon Event ID 1: esentutl.exe with CommandLine containing the \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy path and '/vss'. Security Event ID 4688 for both processes if command line auditing is enabled. Microsoft-Windows-StorageService/Operational events for VSS snapshot creation. Sysmon Event ID 11 (File Create) for SYSTEM.bak in %TEMP%.
- Test 2Diskshadow Script-Based Shadow Copy and File Exposure
Expected signal: Sysmon Event ID 1: diskshadow.exe with CommandLine containing '/s' and the .dsh script path. Sysmon Event ID 11: creation of dsh_test.dsh in %TEMP% by powershell.exe. Security Event ID 4688 for diskshadow.exe. Microsoft-Windows-StorageService/Operational events for VSS snapshot creation via diskshadow. If drive Z: is exposed, subsequent file access on Z: generates normal file system events attributed to the accessing process.
- Test 3ntdsutil IFM Media Creation for NTDS Extraction
Expected signal: Sysmon Event ID 1: ntdsutil.exe with CommandLine containing 'ifm', 'create full', and the output path. Security Event ID 4688 for ntdsutil.exe. On a domain controller: Security Event ID 4656/4663 for NTDS directory handle access, and Sysmon Event ID 11 for file creation of ntds.dit and SYSTEM in the IFM output directory. On a non-DC: ntdsutil exits with an error (0x80070003 - path not found for NTDS) but process creation event still fires.
- Test 4PowerShell Direct Physical Drive Read Simulation
Expected signal: Sysmon Event ID 1: powershell.exe with CommandLine containing '\\.\PhysicalDrive0' and 'FileOpen'. Security Event ID 4688 if command line auditing is enabled. If Object Access auditing covers raw disk handles: Security Event ID 4656 for handle request to PhysicalDrive0. This command will fail with 'Access Denied' for non-elevated users, but the process creation event still fires and matches the detection pattern.
References (10)
- https://attack.mitre.org/techniques/T1006/
- https://github.com/PowerShellMafia/PowerSploit/blob/master/Exfiltration/Invoke-NinjaCopy.ps1
- https://lolbas-project.github.io/lolbas/Binaries/Esentutl/
- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/vssadmin
- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/diskshadow
- https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/cc753455(v=ws.11)
- https://www.microsoft.com/en-us/security/blog/2023/10/25/octo-tempest-crosses-boundaries-to-facilitate-extortion-encryption-and-destruction/
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-038a
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1006/T1006.md
- http://www.codeproject.com/Articles/32169/FDump-Dumping-File-Sectors-Directly-from-Disk-usin
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