MFT

Windows DFIR notes are no longer maintained on InfoSec-Notes. Updated versions can be found on: artefacts.help.

Overview

The Master File Table (MFT), filename $MFT, is the main element of any New Technology File System (NTFS) partition. The Partition Boot Sector $Boot metadata file, which starts at sector 0 and can be up to 16 sectors long, describes the basic NTFS volume information and indicates the location of the $MFT.

The MFT contains an entry for all existing files written on the partition. Deleted files that were once written on the partition may also (temporally) still have a file record in the MFT.

Each file record in the MFT notably includes:

  • The filename.

  • The file size.

  • The file unique (under the NTFS volume) Security ID in the $STANDARD_INFORMATION attribute.

  • The file creation, last modified, last accessed, and last changed SI timestamps in the $STANDARD_INFORMATION attribute.

  • The file creation, last modified, last accessed, and last changed FN timestamps in the $FILE_NAME attribute.

  • Whether the file record is in use. When a file is deleted from the volume, its associated MFT file record is set as no longer in use, but is not directly deleted during the file deletion process. Metadata information, and content for MFT resident files, can thus be retrieved for recently deleted files (as long as the file record is not overwritten by a new entry).

The $MFT file has both the Hidden (H) and System (S) attributes and will thus not be shown by the Windows Explorer application or the dir utility by default.

$Bitmap

The $Bitmap file tracks the allocation status (allocated or unused) of the clusters of the volume. Each cluster is associated with a bit, set to 0x1 if the cluster is in use.

Upon deletion of a non resident file, the $Bitmap file is updated to tag the cluster(s) associated with the file as free. The clusters are not overwritten during the deletion process, and the file data can thus be carved as long as the cluster(s) are not re-used.

$Secure

The $Secure file contains the security descriptor for all the files and folders on a NTFS volume. The security descriptors are stored within the $SDS named data stream of the $Secure file. The $Secure file additionally defines two other named streams ($SDH and $SII) for lookup in the $SDS stream.

Each file or folder is referenced in the $Secure file with its volume-unique Security ID and security descriptor. The Security ID of the file is referenced in the MFT file record associated with the file (in the $STANDARD_INFORMATION attribute). While no metadata information are present in the $Secure file (only the file's security descriptor), the file's Security ID can be used to map the file's information / data from the MFT to its security descriptor in the $Secure file.

The security descriptor (SECURITY_DESCRIPTOR data structure) references:

  • The owner of the file (as a pointer to a SID structure).

  • The access rights to the file in the Discretionary Access Control List (DACL) attribute.

  • The audit rights that control how access is audited (which access will generate events) in the System Access Control List (SACL) attribute.

$LogFile

The $LogFile is part of a journaling feature of NTFS, activated by default, which maintains a low-level record of changes made to the NTFS volume. Every disk operation is journalized prior to being committed. In case of failure, such as a crash during an update, the $LogFile can be used to revert disk operations. As low-level operations are journalized, the $LogFile contains very limited historical data, usually only of the last few hours at most.

$STANDARD_INFORMATION vs $FILE_NAME

The $STANDARD_INFORMATION and $FILE_NAME attributes are updated differently for the same file action. The changes produced on the attributes for a file creation, access, modification, renaming, etc. can be found on the SANS Windows Forensic Analysis poster.

For more information on Windows timestamps, refer to the [DFIR] Windows - Timestamps note.

Parsing

MFTECmd

The MFTECmd utility can parse and extract information from the $MFT (as well as other filesystem artefacts such as the UsnJrnl's $J stream, the file ownership $Secure:$SDS data stream, and the transaction log file $Logfile).

# A $MFT file on a mounted partition should be specified.
# For instance, to extract $MFT data from a forensics image, the image should first be mounted and the $MFT specified as <DRIVER_LETTER:\$MFT to MFTECmd.exe.

MFTECmd.exe -f '<$MFT_FILE>' --csv <OUTPUTDIR_PATH>

Mft2Csv

The Mft2Csv utility can parse, decode, and log information from the MFT to a CSV. It supports getting the $MFT from a variety of sources and notably:

  • a raw/dd image of disk or partition

  • an extracted $MFT file

  • a live host

Note that Mft2Csv can only output in one format at a time.

# Get machine time zone
tzutil /g

# Opens a GUI
Mft2Csv.exe

# Command line
# UTC + 1
Mft2Csv.exe /Volume:<NTFS_VOLUME> /OutputPath:"<OUTPUT_FOLDER>" /OutputFormat:all /TimeZone:"<-12.00 ... 14.00>" /Separator:"<CSV_SEPARATOR>"
Mft2Csv.exe /MftFile:<MFT_FILE> /OutputPath:"<OUTPUT_FOLDER>" /OutputFormat:all /TimeZone:"<-12.00 ... 14.00>" /Separator:"<CSV_SEPARATOR>"

Mft2Csv will produce a CSV containing all the MFT entries. To parse the CSV, the Python utility q can be used to run SQL-like queries directly against the CSV:

q -d '|' -H -O "SELECT FN_FileName,FilePath,FileSizeBytes,SI_FilePermission,SI_CTime,SI_ATime,SI_MTime,SI_RTime,FN_CTime,FN_ATime,FN_MTime,FN_RTime FROM <MFT_CSV_PATH> WHERE SI_CTime >= '<YYYY-MM-DD HH:mm:SS.0000000>' AND SI_CTime < '<<YYYY-MM-DD HH:mm:SS.9999999>' ORDER BY SI_CTime"

PowerShell PowerForensics Get-ForensicFileRecord

The PowerShell cmdlet Get-ForensicFileRecord of the PowerForensics suite parses the $MFT file and returns an array of FileRecord entries. By default, Get-ForensicFileRecord will parse the $MFT file on the C:\ drive.

Get-ForensicFileRecord can be used to retrieve record for a specified file.

# Deploy the PowerShell PowerForensics module
.\PowerForensics.psd1
Import-Module .\PowerForensics.psd1

Get-ForensicFileRecord | Out-File <OUTPUT_FILE>
Get-ForensicFileRecord -VolumeName <NTFS_VOLUME> | Out-File <OUTPUT_FILE>
Get-ForensicFileRecord -MftPath <EXPORTED_MFT_PATH> | Out-File <OUTPUT_FILE>

Get-ForensicFileRecord -Path <FILE_TO_GET_RECORD_OF>

References

https://docs.velociraptor.app/docs/forensic/ntfs/

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