Difference between pages "Nickfile (NK2)" and "Windows Prefetch File Format"

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[[Microsoft]] [[Outlook]] uses the '''Nickfile (NK2)''' to store e-mail address aliases.
+
A Windows Prefetch file consists of one file header and multiple file sections with different content. Not all content has an obvious forensic value.
  
The file type is also known as the Outlook AutoComplete File or the Nickname file.
+
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.
  
== MIME types ==
+
== Characteristics ==
 +
Integer values are stored in little-endian.
  
The actual mime type of the NK2 format is unspecified
+
Strings are stored as UTF-16 little-endian without a byte-order-mark (BOM).
  
== File signature ==
+
Timestamps are stored as Windows Filetime in UTC.
  
The NK2 has the following file signature:
+
== Header ==
hexadecimal: 0D F0 AD BA
+
  
Note that other sources claim that the file signature is
+
This format has been observed on Windows XP, ...  will need to be modified for Vista/Win7 format
hexadecimal: 0D F0 AD BA 0A 00 00 00
+
  
== Contents ==
+
{| class="wikitable"
 +
|-
 +
! Field
 +
! Offset
 +
! Length
 +
! Type
 +
! Notes
 +
|-
 +
| H1
 +
| 0x0000
 +
| 4
 +
| DWORD
 +
| Format version (see format version section below)
 +
|-
 +
| H2
 +
| 0x0004
 +
| 4
 +
| DWORD
 +
| Signature 'SCCA' (or in hexadecimal representation 0x53 0x43 0x43 0x4)
 +
|-
 +
| 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 29 code units, 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)
 +
|-
 +
|}
  
The NK2 basically contains a list of items. The attributes of these items are defined by the [[Microsoft]] [[Outlook]] [[Message API (MAPI)]].
+
The following part of the header is likely to be format version dependent structure for format version 0x11.
  
== External Links ==
+
{| class="wikitable"
 +
|-
 +
! Field
 +
! Offset
 +
! Length
 +
! Type
 +
! Notes
 +
|-
 +
| 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)
 +
|-
 +
|}
  
* [https://googledrive.com/host/0B3fBvzttpiiSZFNVS2JjWkNnelk/Nickfile%20(NK2)%20format.pdf Nickfile (NK2) format specification], by the [[libnk2|libnk2 project]]
+
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.
* [https://googledrive.com/host/0B3fBvzttpiiSRlR1QkU5Vk43ZWs/MAPI%20definitions.pdf MAPI definitions], by the [[libpff|libpff project]]
+
  
[[Category:File Formats]]
+
=== Format version ===
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Value
 +
! Windows version
 +
|-
 +
| 0x11
 +
| Windows XP, Windows 2003
 +
|-
 +
| 0x17
 +
| Windows Vista, Windows 7
 +
|-
 +
| 0x1a
 +
| Windows 8.1
 +
|-
 +
|}
 +
 
 +
== Section A and B ==
 +
 
 +
The content of these two sections is unknown.
 +
 
 +
== Section C ==
 +
 
 +
== Section D ==
 +
 
 +
Section D contains one or more subsections. The number is (most likely) determined by the DWORD at file offset 0x0070. Each subsection refers to directories on an identified volume.
 +
 
 +
In this section, 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)
 +
|-
 +
| DH2
 +
| +0x0004
 +
| 4
 +
| DWORD
 +
| Length of volume string (nr of characters, including terminating U+0000)
 +
|-
 +
| DH3
 +
| +0x0008
 +
| 8
 +
| FTIME
 +
| (File time)
 +
|-
 +
| DH4
 +
| +0x0010
 +
| 4
 +
| DWORD
 +
| Volume serial number of volume indicated by volume string
 +
|-
 +
| DH5
 +
| +0x0014
 +
| 4
 +
| DWORD
 +
| ? Offset to section DHS1
 +
|-
 +
| DH6
 +
| +0x0018
 +
| 4
 +
| DWORD
 +
| ? Length of section DHS1 (in bytes)
 +
|-
 +
| DH7
 +
| +0x001C
 +
| 4
 +
| DWORD
 +
| ? Offset to section DHS2
 +
|-
 +
| DH8
 +
| +0x0020
 +
| 4
 +
| DWORD
 +
| ? Nr of strings in section DHS2
 +
|-
 +
| ?
 +
| +0x0024
 +
| ?
 +
| ?
 +
| ? additional 28 bytes (includes one timestamp?)
 +
|}
 +
 
 +
 
 +
 
 +
If all the executables and libraries referenced in the C section are from one single disk volume, there will be only one section in the D section. If multiple volumes are referenced by section C, section D will contain multiple sections.  (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 will 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).

Revision as of 05:19, 20 October 2013

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.

Contents

Characteristics

Integer values are stored in little-endian.

Strings are stored as UTF-16 little-endian without a byte-order-mark (BOM).

Timestamps are stored as Windows Filetime in UTC.

Header

This format has been observed on Windows XP, ... will need to be modified for Vista/Win7 format

Field Offset Length Type Notes
H1 0x0000 4 DWORD Format version (see format version section below)
H2 0x0004 4 DWORD Signature 'SCCA' (or in hexadecimal representation 0x53 0x43 0x43 0x4)
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 29 code units, 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)

The following part of the header is likely to be format version dependent structure for format version 0x11.

Field Offset Length Type Notes
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.

Format version

Value Windows version
0x11 Windows XP, Windows 2003
0x17 Windows Vista, Windows 7
0x1a Windows 8.1

Section A and B

The content of these two sections is unknown.

Section C

Section D

Section D contains one or more subsections. The number is (most likely) determined by the DWORD at file offset 0x0070. Each subsection refers to directories on an identified volume.

In this section, all offsets are assumed to be counted from the start of the D section.

Field Offset Length Type Notes
DH1 +0x0000 4 DWORD Offset to volume string (Unicode, terminated by U+0000)
DH2 +0x0004 4 DWORD Length of volume string (nr of characters, including terminating U+0000)
DH3 +0x0008 8 FTIME (File time)
DH4 +0x0010 4 DWORD Volume serial number of volume indicated by volume string
DH5 +0x0014 4 DWORD  ? Offset to section DHS1
DH6 +0x0018 4 DWORD  ? Length of section DHS1 (in bytes)
DH7 +0x001C 4 DWORD  ? Offset to section DHS2
DH8 +0x0020 4 DWORD  ? Nr of strings in section DHS2
 ? +0x0024  ?  ?  ? additional 28 bytes (includes one timestamp?)


If all the executables and libraries referenced in the C section are from one single disk volume, there will be only one section in the D section. If multiple volumes are referenced by section C, section D will contain multiple sections. (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 will 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).