WinDbg PE files dumping library

This is a WinDbg debugger extension library providing various tools to analyze, dump and fix (restore) Microsoft Portable Executable files for both 32 (PE) and 64-bit (PE+) platforms. The library is intended to be used by advanced reverse engineers and malware analysts with their work with malicious software, packers or viruses.

Features

dumpext provides a rich set of features like:

• Support for both 32/64-bit PE files formats,
• Informations related to virtually all PE files details like headers, sections, exports, imports (including delayed and bound), thread local storage (TLS), relocations, resources tree, exception spec. (x64/ia64 platforms) and more...
• Offset specific informations like memory address to RVA, owning module, file pointer etc.
• Support for PE CRC restore,
• Support for originally bound imports restore,
• Various heuristic scans (IAT/IDT) for corrupted/destroyed imports,
• IDT table localization,
• Imports tables fixing with full forwarders support,
• Resources fixing,
• Various PE headers optimizations and fixing methods (useful for advanced packers which may remove some crucial PE file information when they are no more needed after the loading phase),
• Dumping fixed PE file or part of the file (sections) into a file.
• And much more...

The features may be divided into two sets:

• Informational: !dump_pe_info, !dump_offset_info, which are useful for wide range of reverse engineers not specifically interested in the PE packers area,
• Executive: the rest of commands; devoted mainly for PE packers analysts and malware reverse engineers working with malicious software using such packers (or other methods of PE files protections).

The library has been used for many years by the author to defeat many various PE files packers (e.g. infamous ASProtect).

dumpext help command output

dumpext: PE files fix, dump & analysis

dump_imp_scan iat [-w] [[-s *|n]|[-a|-r addr -l len]] [mod_base]
    IAT imports scanning at specified memory range or of a given module with a
    base mod_base. This is the most generic method for imports scanning.
    -s,r,a,l: Scanning range specification, that is a section number ('*' denotes
        all sections) or a memory range specified by an address or rva.
    -w: Write resolved imports to the config file.
dump_imp_scan idt [-w] [-a|-r addr [-l len]] [mod_base]
    IDT imports scanning at specified address of the IDT table or of a given
    module with a base mod_base. This command may be used only if IDT location
    is known and the IDT is not corrupted.
    -a,r,l: Specifies an address or rva of the IDT table with an optional length
        constraint.
    -w: Write resolved imports to the config file.

dump_pe [-s *|n] [mod_base]
    Dump a module with an address mod_base to a file. The configuration file is
    inspected for parameters controlling the dump (e.g. sections specification,
    various methods of fixing etc.)
    -s: Specifies section to extract into separate file. '*' denotes all sections.

dump_pe_info [header] [-m] [-h] [-d] [-s] [mod_base]
    Show PE details contained in the headers' part of a module with the address
    mod_base. If no options are provided all PE details except the DOS header
    are printed out.
    -m: DOS header.
    -h: PE headers (file and optional).
    -d: PE directories info.
    -s: Sections table.
dump_pe_info export|import|bimport|dimport|debug|lconf|rsrc|tls|reloc|except
             [-c|-C] [-x] [-v|-V] [-a|-r addr [-l len]] [mod_base]
    Show PE directory details at specified addr or of a given module with a base
    mod_base.
    -c,C: {rsrc} Show resource capacity details (-c); exclusively (-C).
    -x: {import} Use the imports spec. format of the config file in the output.
    -v,V: {except} Show verbose (-v) and even more verbose (-V) exception table
        details. All the provided informations are platform specific.
    -a,r: {all cases} Specifies an address or rva of the directory.
    -l: {import,bimport,dimport,reloc,except} An optional length constraint.

dump_offset_info [-v] {-a addr}|{-f ftpr [mod_base]}
    Show address or file pointer details.
    -a: Address details.
    -f: File pointer details.
    -v: Show virtual memory details.

dump_sects_chrt [-c] [mod_base]
    Analyse PE headers to recognize sections names and characteristics. Show
    the result in the format ready to use in the configuration file. Useful for
    packers destroying mentioned data.
    -c: Read and take into account the configuration (PE headers, sections,
        directories).

dump_serach idt [-x] [[-s *|n]|[-a|-r addr -l len]] [mod_base]
    Search for and analyse the IDT table with IAT addresses matching the ones
    specified in the imports spec. in the config file. The command shall be used
    for searching destination location of the fixed imports with not modified
    IDT table.
    -s,r,a,l: Searching range specification, that is a section number ('*'
        denotes all sections) or a memory range specified by an address or rva.
    -x: Silent mode. In case of successful search the result is printed in the
        format used by the configuration file.

dump_conf [conf_file]
    Set configuration file to conf_file. If the file is not specified the current
    configuration file is displayed.

help
    Show this help.

Compiling and Installing

Prerequisites:

• MS SDK with cl, link and nmake; no need for MS Visual Studio,
• Debugging Tools for Windows with its SDK,

Compilation:

Set required building environment depending on your target platform (x86/x64/ia64, debug/release etc.) by calling MS SDK's SetEnv.Cmd script with proper arguments and make the library:

nmake

The result is dumpext.dll library located in the sources directory. Install it by:

nmake install

Loading and some simple examples

I. Loading:

0:000> .load dumpext

II. Help info:

0:000> !dumpext.help

III. PE headers details. Example of usage for 64-bit notepad.exe (the output is printed in the dumpext's configuration file format):

0:000> !dump_pe_info notepad
INFO: Base address of the module: 0x00000000ffd50000 [notepad.exe]

[file_header]
Machine = 0x8664   ; x64
NumberOfSections = 0x0006
TimeDateStamp = 0x4A5BC9B3
PointerToSymbolTable = 0x00000000
NumberOfSymbols = 0x00000000
SizeOfOptionalHeader = 0x00F0
Characteristics = 0x0022   ; exe|big_addr_aware

[optional_header]
Magic = 0x020B   ; PE32+
MajorLinkerVersion = 0x09
MinorLinkerVersion = 0x00
SizeOfCode = 0x0000A800
SizeOfInitializedData = 0x00025800
SizeOfUninitializedData = 0x00000000
AddressOfEntryPoint = 0x00003570   ; addr: 0x00000000FFD53570, section 1
BaseOfCode = 0x00001000   ; addr: 0x00000000FFD51000, section 1
ImageBase = 0x00000000FFD50000
SectionAlignment = 0x00001000
FileAlignment = 0x00000200
MajorOperatingSystemVersion = 0x0006
MinorOperatingSystemVersion = 0x0001
MajorImageVersion = 0x0006
MinorImageVersion = 0x0001
MajorSubsystemVersion = 0x0006
MinorSubsystemVersion = 0x0001
Win32VersionValue = 0x00000000
SizeOfImage = 0x00035000
SizeOfHeaders = 0x00000600
CheckSum = 0x00000000
Subsystem = 0x0002   ; win gui
DllCharacteristics = 0x8140   ; dyn_base|nx_compat|term_aware
SizeOfStackReserve = 0x0000000000080000
SizeOfStackCommit = 0x0000000000011000
SizeOfHeapReserve = 0x0000000000100000
SizeOfHeapCommit = 0x0000000000001000
LoaderFlags = 0x00000000
NumberOfRvaAndSizes = 0x00000010

[directories]
ExportTab.rva = 0x00000000
ExportTab.size = 0x00000000
ImportTab.rva = 0x0000CFF8   ; addr: 0x00000000FFD5CFF8, section 2
ImportTab.size = 0x0000012C
ResourceTab.rva = 0x00014000   ; addr: 0x00000000FFD64000, section 5
ResourceTab.size = 0x0001F160
ExceptionTab.rva = 0x00013000   ; addr: 0x00000000FFD63000, section 4
ExceptionTab.size = 0x000006B4
CertificateTab.rva = 0x00000000
CertificateTab.szie = 0x00000000
BaseRelocTab.rva = 0x00034000   ; addr: 0x00000000FFD84000, section 6
BaseRelocTab.size = 0x000000B8
Debug.rva = 0x0000B710   ; addr: 0x00000000FFD5B710, section 1
Debug.size = 0x00000038
Architecture.rva = 0x00000000
Architecture.size = 0x00000000
GlobalPtr.rva = 0x00000000
GlobalPtr.size = 0x00000000
TLSTab.rva = 0x00000000
TLSTab.size = 0x00000000
LoadConfigTab.rva = 0x00000000
LoadConfigTab.size = 0x00000000
BoundImportTab.rva = 0x000002E0   ; addr: 0x00000000FFD502E0, header
BoundImportTab.size = 0x00000138
IAT.rva = 0x0000C000   ; addr: 0x00000000FFD5C000, section 2
IAT.size = 0x000007F0
DelayImportDesc.rva = 0x00000000
DelayImportDesc.size = 0x00000000
CLRRuntimeHeader.rva = 0x00000000
CLRRuntimeHeader.size = 0x00000000
Reserved.rva = 0x00000000
Reserved.size = 0x00000000

[sections]
1.Name = .text
1.VirtualSize = 0x0000A770
1.VirtualAddress = 0x00001000   ; addr: 0x00000000ffd51000
1.SizeOfRawData = 0x0000A800
1.PointerToRawData = 0x00000600
1.PointerToRelocations = 0x00000000
1.PointerToLinenumbers = 0x00000000
1.NumberOfRelocations = 0x0000
1.NumberOfLinenumbers = 0x0000
1.Characteristics = 0x60000020   ; code|exec|read
2.Name = .rdata
2.VirtualSize = 0x00003160
2.VirtualAddress = 0x0000C000   ; addr: 0x00000000ffd5c000
2.SizeOfRawData = 0x00003200
2.PointerToRawData = 0x0000AE00
2.PointerToRelocations = 0x00000000
2.PointerToLinenumbers = 0x00000000
2.NumberOfRelocations = 0x0000
2.NumberOfLinenumbers = 0x0000
2.Characteristics = 0x40000040   ; init_data|read
3.Name = .data
3.VirtualSize = 0x00002844
3.VirtualAddress = 0x00010000   ; addr: 0x00000000ffd60000
3.SizeOfRawData = 0x00001800
3.PointerToRawData = 0x0000E000
3.PointerToRelocations = 0x00000000
3.PointerToLinenumbers = 0x00000000
3.NumberOfRelocations = 0x0000
3.NumberOfLinenumbers = 0x0000
3.Characteristics = 0xC0000040   ; init_data|read|write
4.Name = .pdata
4.VirtualSize = 0x000006B4
4.VirtualAddress = 0x00013000   ; addr: 0x00000000ffd63000
4.SizeOfRawData = 0x00000800
4.PointerToRawData = 0x0000F800
4.PointerToRelocations = 0x00000000
4.PointerToLinenumbers = 0x00000000
4.NumberOfRelocations = 0x0000
4.NumberOfLinenumbers = 0x0000
4.Characteristics = 0x40000040   ; init_data|read
5.Name = .rsrc
5.VirtualSize = 0x0001F160
5.VirtualAddress = 0x00014000   ; addr: 0x00000000ffd64000
5.SizeOfRawData = 0x0001F200
5.PointerToRawData = 0x00010000
5.PointerToRelocations = 0x00000000
5.PointerToLinenumbers = 0x00000000
5.NumberOfRelocations = 0x0000
5.NumberOfLinenumbers = 0x0000
5.Characteristics = 0x40000040   ; init_data|read
6.Name = .reloc
6.VirtualSize = 0x000000B8
6.VirtualAddress = 0x00034000   ; addr: 0x00000000ffd84000
6.SizeOfRawData = 0x00000200
6.PointerToRawData = 0x0002F200
6.PointerToRelocations = 0x00000000
6.PointerToLinenumbers = 0x00000000
6.NumberOfRelocations = 0x0000
6.NumberOfLinenumbers = 0x0000
6.Characteristics = 0x42000040   ; init_data|discardable|read

IV. Imports details. Example of usage for 64-bit notepad.exe (trimmed output):

0:000> !dump_pe_info import notepad
INFO: Base address of the module: 0x00000000ffd50000 [notepad.exe]
INFO: IDT table at: 0x00000000ffd5cff8
INFO: RVA provided in [], 'h:' denotes hints

0x00000000ffd5cff8[0x0000CFF8] ADVAPI32.dll IDT Entry:
  ILT at:          0x00000000ffd5d1e8[0x0000D1E8]
  Timestamp:       0xFFFFFFFF   ; new-type bind
  Forwarder chain: 0xFFFFFFFF
  Module name at:  0x00000000ffd5d1d4[0x0000D1D4]
  IAT at:          0x00000000ffd5c000[0x0000C000]
 Imports:
  0x000007fefee047b0: 0x00000000ffd5d9d8[0x0000D9D8] h:0x027E RegSetValueExW
  0x000007fefee0f050: 0x00000000ffd5d9ea[0x0000D9EA] h:0x026E RegQueryValueExW
  0x000007fefee047e0: 0x00000000ffd5d9fe[0x0000D9FE] h:0x023C RegCreateKeyW
  0x000007fefee14de0: 0x00000000ffd5da0e[0x0000DA0E] h:0x0230 RegCloseKey
  0x000007fefee14db0: 0x00000000ffd5da1c[0x0000DA1C] h:0x0261 RegOpenKeyExW
  0x000007fefee14df0: 0x00000000ffd5da2c[0x0000DA2C] h:0x0180 IsTextUnicode
  0x000007fefee0ad44: 0x00000000ffd5da3c[0x0000DA3C] h:0x0057 CloseServiceHandle
  0x000007fefedfe7c8: 0x00000000ffd5da52[0x0000DA52] h:0x01F9 OpenSCManagerW
  0x000007fefedfe7e0: 0x00000000ffd5da64[0x0000DA64] h:0x01FB OpenServiceW
  0x000007fefedfec1c: 0x00000000ffd5da74[0x0000DA74] h:0x0224 QueryServiceConfigW
...

V. Export details. Example of usage for 64-bit kernel32.dll (trimmed output):

0:000> !dump_pe_info export kernel32
INFO: Base address of the module: 0x0000000076ba0000 [C:\Windows\system32\kernel32.dll]
INFO: Export Directory at: 0x0000000076c3fffc
INFO: RVA provided in [], '#' precedes ordinals, 'h:' denotes hints

0x0000000076c3fffc[0x0009FFFC] KERNEL32.dll Export Directory:
  Characteristics:      0x00000000
  Timestamp:            0x556354C0
  Major version:        0x0000
  Minor version:        0x0000
  Module name at:       0x0000000076c43684[0x000A3684]
  Ordinal base:         0x00000001
  Address tab. entries: 0x00000570
  Number of name ptrs:  0x00000570
  Export addr table at: 0x0000000076c40024[0x000A0024]
  Name ptrs table at:   0x0000000076c415e4[0x000A15E4]
  Ordinals table at:    0x0000000076c42ba4[0x000A2BA4]
 Exports:
  0x0000000076c4a1c0[0x000AA1C0]: #0x0001 h:0x0000 0x0000000076c43691[0x000A3691] AcquireSRWLockExclusive -> NTDLL.RtlAcquireSRWLockExclusive
  0x0000000076c4a1e1[0x000AA1E1]: #0x0002 h:0x0001 0x0000000076c436a9[0x000A36A9] AcquireSRWLockShared -> NTDLL.RtlAcquireSRWLockShared
  0x0000000076ba3c80[0x00003C80]: #0x0003 h:0x0002 0x0000000076c436be[0x000A36BE] ActivateActCtx
  0x0000000076c06a10[0x00066A10]: #0x0004 h:0x0003 0x0000000076c436cd[0x000A36CD] AddAtomA
  0x0000000076c069b0[0x000669B0]: #0x0005 h:0x0004 0x0000000076c436d6[0x000A36D6] AddAtomW
...

VI. Resources tree details (trimmed output):

0:000> !dump_pe_info rsrc notepad
INFO: Base address of the module: 0x00000000ffd50000 [notepad.exe]
INFO: Resources at: 0x00000000ffd64000
INFO: RVA provided in [], '#' precedes numeric ids

0x00000000ffd64000[0x00014000] RootDir
  Characteristics:0x00000000
  Timestamp:      0x00000000
  Major version:  0x0000
  Minor version:  0x0000
  Total entries:  0x0001+0x0005   ; names+ids
 Types:
.1  0x00000000ffd64000+0x0040[0x00014040] TypeDir "MUI"; name at: 0x00000000ffd64000+0x0400[0x00014400]
      Characteristics:0x00000000
      Timestamp:      0x00000000
      Major version:  0x0000
      Minor version:  0x0000
      Total entries:  0x0000+0x0001   ; names+ids
     Names/IDs:
.1.1    0x00000000ffd64000+0x0130[0x00014130] NameDir #0x0001
          Characteristics:0x00000000
          Timestamp:      0x00000000
          Major version:  0x0000
          Minor version:  0x0000
          Total entries:  0x0000+0x0001   ; names+ids
         Instances [per language]:
.1.1.1      0x00000000ffd64000+0x02E0[0x000142E0] LangData #0x0409 en-us
              Data at:  0x00000000ffd83070[0x00033070]
              Size:     0x000000F0
              Code page:0x00000000
              Reserved: 0x00000000
.2  0x00000000ffd64000+0x0058[0x00014058] TypeDir #0x0002 RT_BITMAP
      Characteristics:0x00000000
      Timestamp:      0x00000000
      Major version:  0x0000
      Minor version:  0x0000
      Total entries:  0x0000+0x0001   ; names+ids
     Names/IDs:
.2.1    0x00000000ffd64000+0x0148[0x00014148] NameDir #0xC809
          Characteristics:0x00000000
          Timestamp:      0x00000000
          Major version:  0x0000
          Minor version:  0x0000
          Total entries:  0x0000+0x0001   ; names+ids
         Instances [per language]:
.2.1.1      0x00000000ffd64000+0x02F0[0x000142F0] LangData #0x0409 en-us
              Data at:  0x00000000ffd648a8[0x000148A8]
              Size:     0x0000561A
              Code page:0x00000000
              Reserved: 0x00000000
...

VII. Address details:

0:000> !dump_offset_info -v -a 0x00000000ffd83070
Address 0x00000000ffd83070 details:
  Module base:  0x00000000ffd50000
  Image name:   notepad.exe
  RVA:          0x00033070
  Contained in: sect 5 [.rsrc], sect mem range: 0x00000000ffd64000..0x00000000ffd8315f
  File ptr:     0x0002F070
Virtual memory info:
  Base address: 0x00000000ffd83000
  Alloc base:   0x00000000ffd50000
  Alloc protect:0x00000080   ; PAGE_EXECUTE_WRITECOPY
  Region size:  0x0000000000002000
  State:        0x00001000   ; MEM_COMMIT
  Protect:      0x00000002   ; PAGE_READONLY
  Type:         0x01000000   ; SEC_IMAGE

0:000> !dump_offset_info -v -a 0x0000000076c40024
Address 0x0000000076c40024 details:
  Module base:  0x0000000076ba0000
  Image name:   C:\Windows\system32\kernel32.dll
  RVA:          0x000A0024
  Contained in: sect 2 [.rdata], sect mem range: 0x0000000076c3c000..0x0000000076ca98c7
  File ptr:     0x0009F624
Virtual memory info:
  Base address: 0x0000000076c40000
  Alloc base:   0x0000000076ba0000
  Alloc protect:0x00000080   ; PAGE_EXECUTE_WRITECOPY
  Region size:  0x000000000006a000
  State:        0x00001000   ; MEM_COMMIT
  Protect:      0x00000002   ; PAGE_READONLY
  Type:         0x01000000   ; SEC_IMAGE

VIII. Dump arbitrary PE file, which has been already loaded into the debugger and not protected by a packer. Example of an output for 64-bit explorer.exe:

0:000> !dump_pe explorer
INFO: Base address of the dumped module: 0x00000000ff1c0000 [explorer.exe]
INFO: Updated optional_header/SizeOfCode from 0x000B7C00 to 0x000B8000
INFO: Updated optional_header/SizeOfInitializedData from 0x00205600 to 0x00207000
INFO: PE headers have been dumped to the output file
INFO: PE sections have been dumped to the output file
INFO: IAT table successfully fixed
INFO: PE checksum written: 0x002C1D54
INFO: Bound imports:
 Import ADVAPI32.dll, Timestamp: 0x556365E3 with 1 forwarder(s)
  Forwarder ntdll.DLL, Timestamp: 0x556366F2
 Import KERNEL32.dll, Timestamp: 0x556366FC with 1 forwarder(s)
  Forwarder ntdll.DLL, Timestamp: 0x556366F2
 Import GDI32.dll, Timestamp: 0x54F7E29C
 Import USER32.dll, Timestamp: 0x4CE7C9F1 with 1 forwarder(s)
  Forwarder ntdll.DLL, Timestamp: 0x556366F2
 Import msvcrt.dll, Timestamp: 0x4EEB033F with 1 forwarder(s)
  Forwarder ntdll.DLL, Timestamp: 0x556366F2
 Import ntdll.DLL, Timestamp: 0x556366F2
 Import SHLWAPI.dll, Timestamp: 0x4CE7C9AB
 Import SHELL32.dll, Timestamp: 0x54DD89C7
 Import ole32.dll, Timestamp: 0x4CE7C92C
 Import OLEAUT32.dll, Timestamp: 0x54754E4A
 Import EXPLORERFRAME.dll, Timestamp: 0x4CE7C6A8
 Import UxTheme.dll, Timestamp: 0x4A5BE093
 Import POWRPROF.dll, Timestamp: 0x4A5BE062
 Import dwmapi.dll, Timestamp: 0x4A5BDF27
 Import slc.dll, Timestamp: 0x4A5BE063
 Import gdiplus.dll, Timestamp: 0x55346E73
 Import Secur32.dll, Timestamp: 0x55636730 with 1 forwarder(s)
  Forwarder SSPICLI.DLL, Timestamp: 0x55636743
 Import RPCRT4.dll, Timestamp: 0x53C339EE
 Import PROPSYS.dll, Timestamp: 0x4CE7C94A
INFO: Imports have been bound
INFO: Dumping process finished with success

The dumped explorer.exe image is now located in WINDBG_DIR\dump.out. Try to execute it.

IX. IAT scanning example for 32-bit kernel32.dll.

0:000> !dump_pe_info imp kernel32
INFO: Base address of the module: 0x7c800000 [C:\WINDOWS\system32\kernel32.dll]
INFO: IDT table at: 0x7c882600
INFO: RVA provided in [], 'h:' denotes hints

0x7c882600[0x00082600] ntdll.dll IDT Entry:
  ILT at:          0x7c882634[0x00082634]
  Timestamp:       0x00000000   ; not bound
  Forwarder chain: 0x00000000
  Module name at:  0x7c882628[0x00082628]
  IAT at:          0x7c801000[0x00001000]
...

So, the IAT is located at 0x7c801000, RVA:0x00001000. Scan the kernel32 module mapped memory for the IAT location:

0:000> !dump_imp_scan iat kernel32
INFO: Base address of the module being scanned: 0x7c800000 [C:\WINDOWS\system32\kernel32.dll]
INFO: IAT scanning starts at: 0x7c801000, size constraint: 0x0624
...
INFO: Resolved imports are:
[imports]
1 = ntdll.dll
1.iat_rva = 0x00001000
1.1 = _wcsnicmp
1.2 = NtFsControlFile
1.3 = NtCreateFile
1.4 = RtlAllocateHeap
...

The IAT was correctly located by the scanner (RVA:0x00001000). Note, the IAT scanning result is presented in the dumpext's configuration file format, ready to be used inside the configuration file to help PE file restoring process automation.

The !dump_imp_scan command automatically detects most proper section to scan for imports by inspecting PE sections table and PE directory (try !dump_pe_info -sd to discover the underlaying logic). The logic is not always accurate, therefore !dump_imp_scan allows to specify section(s) intended to be scanned (-s option).

Configuration file

!dump_pe, !dump_serach idt and !dump_sects_chrt (optionally) commands use a configuration file which controls their work. By default the file is looked in the same directory as the extension library under dumpext.conf name. This can be changed using !dump_conf command.

Refer to the dumpext.conf file in the source directory for more details.

License

GNU GENERAL PUBLIC LICENSE v2. See LICENSE file for details.