EXE File format

PE EXE (Windows 32Bit EXE, DLL, OCX, etc)
MZ EXE Header This contains information needed to run the DOS STUB
Extended MZ Header Offset 3ch points to the PE header
DOS STUB Usually displays 'Requires windows to run' or similar message
PE Header Contains info needed to run the Win32 Bit
Object table Information about objects present in file

MZ EXE Header
0000 Word ID 'MZ' - Exe file tag
0002 Word Number of bytes in last 512byte page of executable
0004 Word Total number of 512byte pages in executable (including last page)
0006 Word Number of relocation entries
0008 Word Header size in paragraphs
000a Word Minimum paragraphs of memory allocated in addition to the code size
000c Word Maximum paragraphs of memory allocated in addition to the code size
000e Word Initial SS relative to start of executable
0010 Word Initial SP
0012 Word Checksum (or 0) of executable
0014 Dword CS:IP relative to start of executable (Entry point)
0018 Word Offset of relocation table
40h for new (NE,LE,LX,W3,PE etc) executables
001a Word Overlay number (0 = main program)

Extended MZ Header
001c Dword ????
0020 Word ?
0022 26Bytes Reserved (0)?
003c Dword Offset of New EXE header from start of file
Or 0 if plain MZ EXE file

PE Header
0000 Dword Signature - 'PE',0,0
0004 Word CPU_TYPE
0000 - Unknown        0162 - MIPS I
014c - 80386             0163 - MIPS II
014d - 80486             0166 - MIPS III
014e - 80586
0006 Word Number of objects in object table
0008 Dword Time/Date stamp
000c 8Bytes Reserved
0014 Word NT Header size (Following Flags)
0016 Word Flags
0 - Program Image       2 - EXE
200 - Fixed address     2000 - Library
0018 Word Reserved
001a Word Linker version
001c 12Bytes Reserved
0028 Dword Entry point RVA - Execution starts here.
002c 8Bytes Reserved
0034 Dword Image Base - start of image in memory
0038 Dword Object align (Power of 2  512-256M)
003c Dword File align (Power of 2  512-64k)
0040 Dword O/S Version required
0044 Dword User Version
0048 Dword Subsys Version
004c Dword Reserved
0050 Dword Image size
0054 Dword Header size
0058 Dword File Checksum (Only used in NT devices)
005c Word Subsystem
0 - Unknown            1 - Native
2 - Win GUI             3 - Win Character
005e Word DLL Flags
0060 Dword Stack reserve size
0064 Dword Stack commit size
0068 Dword Heap reserve size
006c Dword Heap commit size
0070 Dword Reserved
0074 Dword Number of RVA/Sizes present NOW
All entrys have   Dword RVA, Size
0078 8Bytes Export table RVA/Size
0080 8Bytes Import table RVA/Size
0088 8Bytes Resource table RVA/Size
0090 8Bytes Exception table RVA/Size
0098 8Bytes Security table RVA/Size
00a0 8Bytes Fixup table RVA/Size
00a8 8Bytes Debug table RVA/Size
00b0 8Bytes Image description RVA/Size
00b8 8Bytes Machine specific RVA/Size
00c0 8Bytes Local thread storage RVA/Size

NE Header
0000 Word ID - 'NE'
0002 Word Linker version
0004 Word Offset of entry table
0006 Word Length of entry table in bytes
0008 Dword File load CRC (Or 0)
000c Byte Program flags bitmapped:
0-1  -  DGroup type       0- none, 1- single shared, 2- multiple, 3- (null)
2      - Global initialization
3      - Protected mode only
4      - 8086 Instructions
5      - 80286 Instructions
6      - 80386 Instructions
7      - 80x87 Instructions
000d Byte Application flags bitmapped:
0-2   - Application type   1- Full screen   2- Compat with Windows/PM  3-Uses Win/PM
3      - OS/2 family application
4      - Reserved?
5      - Errors in image/executable
6      - Non-conforming program
7      - DLL or driver (SS:SP info invalid) CS:IP -> Far init routine called with ax=mod handle. returns ax=0 on failure, ax nonzero on successful initialization.
000e Byte Auto data segment index
0010 Word Initial local heap size
0012 Word Initial stack size
0014 Dword Entry point CS:IP (CS is index into segment table)
0018 Dword Initial stack pointer SS:SP (SS is index into segment table)
001c Word Segment count
001e Word Module reference count
0020 Word Size of nonresident names table in bytes
0022 Word Offset of segment table
0024 Word Offset of resource table
0026 Word Offset of resident names table
0028 Word Offset of module reference table
002a Word Offset of imported names table
002c Dword Offset from start of file to nonresident names table
0030 Word Count of moveable entry point listed in entry table
0032 Word File alignment size shift count (0 is equivalent to 9) Default 512-byte pages
0034 Word Number of resource table entries
0036 Byte Target operating system
0- unknown
1- OS/2
2- Windows
3- European DOS 4.x
4- Windows 386
5- BOSS (Borland operating system services)
0037 Byte Other OS/2 EXE flags bitmapped:
0- Long filename support
1- 2.x protected mode
2- 2.x proportional fonts
3- EXE has gangload area
0038 Word Offset to return thunks or start of gangload area
003a Word Offset to segment reference thunks or length of gangload area
003c Word Minimum code swap area size
003e Word Expected windows version