![]() If data are nonresident, then “data runs,” or where data are located on the disk, need to be translated.Įxample code for parsing $DATA attribute data runs is very involved and is not presented here. This is generally true for short text files, for example, or other files less than 700 bytes. If the nonresident flag in the attribute header is not set, then the content of the file is resident within the $DATA attribute of the MFT entry, following the header and two additional structures. This attribute contains or refers to the actual content of the file. The final attribute we discuss is the $DATA attribute (identifier 0x80, or 128). When the header is parsed, pseudocode for this may be represented as follows: In short, from these two values, we can determine if the entry is allocated or deleted, and if it is for a file or directory. Finally, we see the flags value, which tells us if the entry is allocated (if the 0x01 bit is set) and if the entry is a directory (if the 0x02 bit is set). Next is the offset with the record to the first attribute if you look at offset 0x38 within the record, you'll see that the first attribute has an identifier of 0x10, or 16. Next is the link count, which refers to the number of directories that have entries for this record (hard links cause this value to incremented). Because this particular MFT entry is actually the first record within the MFT and refers to the file “$MFT,” it stands to reason that the sequence number is 1. Then we see the sequence number or value, which is incremented when the entry is allocated or unallocated. MFT record header items (in little Endian order).Īs illustrated in Figure 4.2 (which is a portion extracted from Figure 4.1), we see the “FILE” signature visible at the beginning of the record. File data eventually is overwritten as the unallocated drive space gets used.įigure 4.2. The file name in the MFT entry can be overwritten due to MFT tree structure reorganization so most of the time file names are not maintained. From a forensics investigator perspective, entries are very interesting because when a file is deleted an entry gets marked as unallocated while the file content on the drive remains intact. The first 16 entries in the MFT belong to system files, such as the MFT itself. The file and directory metadata is stored as an MFT entry that is 1024 bytes in size. ![]() ![]() The metadata includes file and folder create dates, entry modified dates, access dates, last written dates, physical and logical file size, and ACLs of the files. It keeps records of all files in a volume, the files' location in the directory, the physical location of the files in on the drive, and file metadata. MFT or $MFT can be considered one of the most important files in the NTFS file system. Cem Gurkok, in Computer and Information Security Handbook (Third Edition), 2017 Master File Table (MFT)
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