Windows Prefetch File Format
A Windows Prefetch file consists of one file header and multiple file sections with different content. Not all content has an obvious forensic value.
As far as have been possible to ascertain, there is no public description of the format. The description below has been synthesised from examination of multiple prefetch files.
This format has been observed on Windows XP, ... will need to be modified for Vista/Win7 format
|H1||0x0000||4||DWORD||? Probably a version number, identifying the file structure. Observed values: 0x11 - Windows XP; 0x17 - Vista, Windows 7|
|H2||0x0004||4||DWORD||? Probably a file magic number. Only observed value: 0x41434353|
|H3||0x0008||4||DWORD?||? Observed values: 0x0F - Windows XP, 0x11 - Windows 7|
|H4||0x000C||4||DWORD||Prefetch file length.|
|H5||0x0010||60||USTR||Name of executable as Unicode string, truncated after character 29 if necessary, and terminated by U+0000. As it appears in the prefetch file file name.|
|H6||0x004C||4||DWORD||The prefetch hash, as it appears in the pf file name.|
|H7||0x0050||4||?||? Observed values: 0 for almost all prefetch files (XP); 1 for NTOSBOOT-B00DFAAD.pf (XP)|
|H8||0x0054||4||DWORD||Offset to section A|
|H9||0x0058||4||DWORD||? Nr of entries in section A|
|H10||0x005C||4||DWORD||Offset to section B|
|H11||0x0060||4||DWORD||Nr of entries in section B|
|H12||0x0064||4||DWORD||Offset to section C|
|H13||0x0068||4||DWORD||Length of section C|
|H14||0x006C||4||DWORD||Offset to section D|
|H15||0x0070||4||DWORD||? Probably the number of entries in the D section header|
|H16||0x0074||4||DWORD||Length of section D|
|H17||0x0078||8||FTIME||Latest execution time of executable (FILETIME)|
|H18||0x0080||16||?||? Possibly structured as 4 DWORD. Observed values: /0x00000000 0x00000000 0x00000000 0x00000000/, /0x47868c00 0x00000000 0x47860c00 0x00000000/|
|H20||0x0094||4||DWORD?||? Observed values: 1, 2, 3, 4, 5, 6 (XP)|
It's worth noting that the name of a carved prefetch file can be restored using the information in field H5 and H6, and its size can be determined by field H4.
Section A and B
The content of these two sections is unknown.
Section D consists of one header, followed by subparts referenced by that header. The headeer can contain several parts itelf: the number appears to be specified by the DWORD at file offset 0x0070.
The basic format of the D header is as follows. All offsets are counted from the start of the D header.
|DH1||0x0000||4||DWORD||Offset to volume string (Unicode, terminated by U+0000)|