Difference between pages "Windows Prefetch File Format" and "JTAG Forensics"

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== Definition ==
 +
=== From Wikipedia ([http://en.wikipedia.org/wiki/Joint_Test_Action_Group http://en.wikipedia.org/wiki/Joint_Test_Action_Group ]): ===
  
A Windows Prefetch file consists of one file header and multiple file sections with different content. Not all content has an obvious forensic value.
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Joint Test Action Group (JTAG) is the common name for what was later standardized as the IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture. It was initially devised for testing printed circuit boards using boundary scan and is still widely used for this application. Today JTAG is also widely used for IC debug ports. In the embedded processor market, essentially all modern processors support JTAG when they have enough pins. Embedded systems development relies on debuggers talking to chips with JTAG to perform operations like single stepping and breakpointing. Digital electronics products such as cell phones or a wireless access point generally have no other debug or test interfaces.
  
As far as have been possible to ascertain, there is no public description of the format. The description below has been synthesised from examination
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=== Forensic Application ===
of multiple prefetch files.
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== Characteristics ==
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JTAG forensics is an acquisition procedure which involves connecting to the Standard Test Access Port (TAPs) on a device and instructing the processor to transfer the raw data stored on connected memory chips. Jtagging supported phones can be an extremely effective technique to extract a full physical image from devices that cannot be acquired by other means.
Integer values are stored in little-endian.
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Strings are stored as UTF-16 little-endian without a byte-order-mark (BOM).
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== Tools and Equipment ==
  
Timestamps are stored as Windows Filetime in UTC.
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* [[JTAG and Chip-Off Tools and Equipment]]
  
== Header ==
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== Procedures ==
  
This format has been observed on Windows XP, ...  will need to be modified for Vista/Win7 format
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* [[JTAG HTC Wildfire S]]
 
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* [[JTAG Huawei TracFone M865C]]
{| class="wikitable"
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* [[JTAG Huawei TracFone H866C]]
|-
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* [[JTAG Huawei U8655]]
! Field
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* [[JTAG Huawei Y301-A1 Valiant]]
! Offset
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* [[JTAG LG L45C TracFone]]
! Length
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* [[JTAG LG P930 (Nitro HD)]]
! Type
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* [[JTAG LG E960 (Nexus 4)]]
! Notes
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* [[JTAG Samsung Galaxy Centura (SCH-S738C)]]
|-
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* [[JTAG Samsung Galaxy S4 (SGH-I337)]]
| H1
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| 0x0000
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| 4
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| DWORD
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| Format version (see format version section below)
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|-
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| H2
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| 0x0004
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| 4
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| DWORD
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| Signature 'SCCA' (or in hexadecimal representation 0x53 0x43 0x43 0x4)
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|-
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| H3
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| 0x0008
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| 4
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| DWORD?
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| Unknown - Values observed: 0x0F - Windows XP, 0x11 - Windows 7, Windows 8.1
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|-
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| H4
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| 0x000C
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| 4
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| DWORD
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| Prefetch file size (or length).
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|-
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| H5
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|0x0010
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| 60
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| USTR
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| The name of the (original) executable as a Unicode (UTF-16 litte-endian string), up to 29 characters and terminated by an end-of-string character (U+0000). This name should correspond with the one in the prefetch file filename.
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|-
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| H6
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|0x004C
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|4
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|DWORD
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|The prefetch hash. This hash value should correspond with the one in the prefetch file filename.
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|-
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| H7
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|0x0050
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|4
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|?
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| Unknown (flags)? Values observed: 0 for almost all prefetch files (XP); 1 for NTOSBOOT-B00DFAAD.pf (XP)
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|-
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|}
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The following part of the header is version dependent. Below the structure for format version 17.
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{| class="wikitable"
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|-
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! Field
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! Offset
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! Length
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! Type
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! Notes
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|-
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| H8
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| 0x0054
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| 4
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| DWORD
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| The offset to section A. The offset is relative from the start of the file.
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|-
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| H9
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| 0x0058
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| 4
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| DWORD
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| The number of entries in section A.
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|-
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| H10
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| 0x005C
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| 4
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| DWORD
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| The offset to section B. The offset is relative from the start of the file.
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|-
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| H11
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| 0x0060
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| 4
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| DWORD
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| The number of entries in section B.
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|-
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| H12
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| 0x0064
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| 4
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| DWORD
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| The offset to section C. The offset is relative from the start of the file.
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|-
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| H13
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| 0x0068
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| 4
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| DWORD
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| Length of section C.
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|-
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| H14
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| 0x006C
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| 4
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| DWORD
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| Offset to section D. The offset is relative from the start of the file.
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|-
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| H15
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| 0x0070
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| 4
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| DWORD
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| Unknown ? (Previously opted: Probably the number of entries in the D section header.)
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|-
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| H16
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| 0x0074
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| 4
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| DWORD
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| Unknown ? (Previously opted: Length of section D)
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|-
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| H17
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| 0x0078
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| 8
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| FTIME
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| Latest execution time (or run time) of executable (FILETIME)
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|-
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| H18
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| 0x0080
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| 16
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| ?
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| Unknown ? Possibly structured as 4 DWORD. Observed values: /0x00000000 0x00000000 0x00000000 0x00000000/, /0x47868c00 0x00000000 0x47860c00 0x00000000/ (don't exclude the possibility here that this is remnant data)
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|-
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| H19
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| 0x0090
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| 4
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| DWORD
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| Execution counter (or run count)
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|-
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| H20
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| 0x0094
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| 4
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| DWORD?
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| Unknown ? Observed values: 1, 2, 3, 4, 5, 6 (XP)
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|-
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|}
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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.
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=== Format version ===
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{| class="wikitable"
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|-
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! Value
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! Windows version
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|-
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| 17 (0x11)
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| Windows XP, Windows 2003
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|-
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| 23 (0x17)
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| Windows Vista, Windows 7
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|-
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| 26 (0x1a)
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| Windows 8.1 (note this could be Windows 8 as well but has not been confirmed)
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|-
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|}
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== Section A ==
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This section contains an array with 20 byte (version 17) or 32 byte (version 23 and 26) entry records.
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The actual format and usage of these entry records is currently not known.
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== Section B ==
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This section contains an array with 12 byte (version 17, 23 and 26) entry records.
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The actual format and usage of these entry records is currently not known.
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== Section C ==
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This section contains an array of UTF-16 little-endian formatted strings with end-of-string characters (U+0000).
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At the end of the section there seems to be alignment padding that can contain remnant values.
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== Section D - Volume information (block) ==
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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.
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In this section, all offsets are assumed to be counted from the start of the D section.
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The following values are version dependent. Below the structure for format version 17.
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+
{| class="wikitable"
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|-
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! Field
+
! Offset
+
! Length
+
! Type
+
! Notes
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|-
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| DH1
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| +0x0000
+
| 4
+
| DWORD
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| Offset to volume string (Unicode, terminated by U+0000)
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|-
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| DH2
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| +0x0004
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| 4
+
| DWORD
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| Length of volume string (nr of characters, including terminating U+0000)
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|-
+
| DH3
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| +0x0008
+
| 8
+
| FTIME
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| (File time)
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|-
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| DH4
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| +0x0010
+
| 4
+
| DWORD
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| Volume serial number of volume indicated by volume string
+
|-
+
| DH5
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| +0x0014
+
| 4
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| DWORD
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| ? Offset to section DHS1
+
|-
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| DH6
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| +0x0018
+
| 4
+
| DWORD
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| ? Length of section DHS1 (in bytes)
+
|-
+
| DH7
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| +0x001C
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| 4
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| DWORD
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| ? Offset to section DHS2
+
|-
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| DH8
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| +0x0020
+
| 4
+
| DWORD
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| ? Nr of strings in section DHS2
+
|-
+
| ?
+
| +0x0024
+
| ?
+
| ?
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| ? 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).
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== See Also ==
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* [[Prefetch]]
+
 
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== External Links ==
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* [https://googledrive.com/host/0B3fBvzttpiiSbl9XZGZzQ05hZkU/Windows%20Prefetch%20File%20(PF)%20format.pdf Windows Prefetch File (PF) format], by the [[libssca|libssca Project]]
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Revision as of 19:35, 23 December 2013

Definition

From Wikipedia (http://en.wikipedia.org/wiki/Joint_Test_Action_Group ):

Joint Test Action Group (JTAG) is the common name for what was later standardized as the IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture. It was initially devised for testing printed circuit boards using boundary scan and is still widely used for this application. Today JTAG is also widely used for IC debug ports. In the embedded processor market, essentially all modern processors support JTAG when they have enough pins. Embedded systems development relies on debuggers talking to chips with JTAG to perform operations like single stepping and breakpointing. Digital electronics products such as cell phones or a wireless access point generally have no other debug or test interfaces.

Forensic Application

JTAG forensics is an acquisition procedure which involves connecting to the Standard Test Access Port (TAPs) on a device and instructing the processor to transfer the raw data stored on connected memory chips. Jtagging supported phones can be an extremely effective technique to extract a full physical image from devices that cannot be acquired by other means.

Tools and Equipment

Procedures