Difference between pages "Windows Prefetch File Format" and "Executable"

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(Volume information - version 17)
 
(DBG, PDB)
 
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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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An executable file is used to perform tasks according to encoded instructions. Executable files are sometimes also referred to as binaries which technically can be considered a sub class of executable files.
  
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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There are multiple families of executable files:
of multiple prefetch files.
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* Scripts; e.g. shell scripts, batch scripts (.bat)
 +
* DOS, Windows executable files (.exe) which can be of various formats like: MZ, PE/COFF, NE
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* ELF
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* Mach-O
  
== Characteristics ==
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== External Links ==
Integer values are stored in little-endian.
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* [http://en.wikipedia.org/wiki/Executable Wikipedia: Executable]
  
Strings are stored as [http://en.wikipedia.org/wiki/UTF-16/UCS-2 UTF-16 little-endian] without a byte-order-mark (BOM).
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=== MZ, PE/COFF ===
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* [http://en.wikipedia.org/wiki/Portable_Executable Wikipedia: Portable Executable]
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* [http://msdn.microsoft.com/en-us/windows/hardware/gg463119.aspx Microsoft PE and COFF Specification]
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* [https://googledrive.com/host/0B3fBvzttpiiSd1dKQVU0WGVESlU/Executable%20(EXE)%20file%20format.pdf MZ, PE-COFF executable file format (EXE)], by the [[libexe|libexe project]], October 2011
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* [http://seclists.org/fulldisclosure/2013/Oct/157 The Internal of Reloc .text], Full Disclosure Mailing list, October 21, 2013
  
Timestamps are stored as [http://msdn2.microsoft.com/en-us/library/ms724284.aspx Windows FILETIME] in UTC.
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=== DBG, PDB ===
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* [http://en.wikipedia.org/wiki/Program_database Wikipedia: Program database]
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* [http://support.microsoft.com/kb/121366 Description of the .PDB files and of the .DBG files], by [[Microsoft]]
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* [http://msdn.microsoft.com/en-us/library/ff553493(v=vs.85).aspx Public and Private Symbols], by [[Microsoft]]
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* [http://msdn.microsoft.com/en-us/library/windows/desktop/ms679293(v=vs.85).aspx DbgHelp Structures], by [[Microsoft]]
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* [https://code.google.com/p/pdbparse/wiki/StreamDescriptions Stream Descriptions], [https://code.google.com/p/pdbparse/ pdbparse project]
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* [http://moyix.blogspot.ch/2007/10/types-stream.html The Types Stream], by [[Brendan Dolan-Gavitt]], October 4, 2007
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* [https://code.google.com/p/google-breakpad/source/browse/trunk/src/google_breakpad/common/minidump_format.h minidump_format.h]
  
== File header ==
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=== Mach-O ===
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* [http://en.wikipedia.org/wiki/Mach-O Wikipedia: Mach-O]
  
{| class="wikitable"
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== Tools ==
|-
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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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| 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) (sometimes referred to as End of File (EOF)).
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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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=== Format version ===
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=== MZ, PE/COFF ===
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* [https://code.google.com/p/pefile/ pefile], multi-platform Python module to read and work with Portable Executable (aka PE) files
  
{| class="wikitable"
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=== PDB ===
|-
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* [https://code.google.com/p/pdbparse/ pdbparse], Open-source parser for Microsoft debug symbols (PDB files)
! 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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=== File information - version 17 ===
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The following part of the file header is version dependent. It is sometime considered part of the file header. 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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== 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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=== Volume information - version 17 ===
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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
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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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| DH1
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| +0x0000
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| 4
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| 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
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| DWORD
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| Length of volume string (nr of characters, including terminating U+0000)
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|-
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| DH3
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| +0x0008
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| 8
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| FILETIME
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| Volume creation time.
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|-
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| DH4
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| +0x0010
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| 4
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| DWORD
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| Volume serial number of volume indicated by volume string
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|-
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| DH5
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| +0x0014
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| 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)
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|-
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| DH7
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| +0x001C
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| 4
+
| DWORD
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| ? Offset to section DHS2
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|-
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| DH8
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| +0x0020
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| 4
+
| DWORD
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| ? Nr of strings in section DHS2
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|-
+
| ?
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| +0x0024
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| ?
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| ?
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| ? additional 28 bytes (includes one timestamp?)
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|}
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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 05:18, 2 November 2013

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Please help to improve this article by expanding it.
Further information might be found on the discussion page.

An executable file is used to perform tasks according to encoded instructions. Executable files are sometimes also referred to as binaries which technically can be considered a sub class of executable files.

There are multiple families of executable files:

  • Scripts; e.g. shell scripts, batch scripts (.bat)
  • DOS, Windows executable files (.exe) which can be of various formats like: MZ, PE/COFF, NE
  • ELF
  • Mach-O

Contents

External Links

MZ, PE/COFF

DBG, PDB

Mach-O

Tools

MZ, PE/COFF

  • pefile, multi-platform Python module to read and work with Portable Executable (aka PE) files

PDB

  • pdbparse, Open-source parser for Microsoft debug symbols (PDB files)