Difference between pages "Windows Prefetch File Format" and "Template:Incident response"

From ForensicsWiki
(Difference between pages)
Jump to: navigation, search
(Section D)
 
 
Line 1: Line 1:
A Windows Prefetch file consists of one file header and multiple file sections with different content. Not all content has an obvious forensic value.
+
[[Category:Incident Response]][[:Category:Incident Response|Incident Response]]
 
+
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.
+
 
+
== Header ==
+
 
+
This format has been observed on Windows XP, ...  will need to be modified for Vista/Win7 format
+
 
+
{| class="wikitable"
+
|-
+
! Field
+
! Offset
+
! Length
+
! Type
+
! Notes
+
|-
+
| 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/
+
|-
+
| H19
+
| 0x0090
+
| 4
+
| DWORD
+
| Execution counter
+
|-
+
| 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 C ==
+
 
+
== Section D ==
+
 
+
Section D begins with one or more headers. The number is (most likely) determined by the DWORD at file offset 0x0070. Each header refers to a hard drive.
+
 
+
In this sections, all offsets are assumed to be counted from the start of the D section.
+
 
+
{| class="wikitable"
+
|-
+
! Field
+
! Offset
+
! Length
+
! Type
+
! Notes
+
|-
+
| DH1
+
| 0x0000
+
| 4
+
| DWORD
+
| Offset to volume string (Unicode, terminated by U+0000)
+
|-
+
|}
+
 
+
If all the executables and libraries referenced in the C section are from one single disk volume, there will be only one header in the D section. If multiple volumes are referenced by section C, section D will contain multiple headers.  (A simple way to force this situation is to copy, say, NOTEPAD.EXE to a USB drive, and start it from that volume. The corresponding prefetch file with have one D header referring to, e.g. \DEVICE\HARDDISK1\DP(1)0-0+4 (the USB drive), and one to, e.g. \DEVICE\HARDDISKVOLUME1\ (where the .DLLs and other support files were found).
+

Latest revision as of 15:25, 12 January 2014

Incident Response