PE module¶
The PE module allows you to create more fine-grained rules for PE files by using attributes and features of the PE file format. This module exposes most of the fields present in a PE header and provides functions which can be used to write more expressive and targeted rules. Let's see some examples:
import "pe"
rule single_section
{
condition:
pe.number_of_sections == 1
}
rule control_panel_applet
{
condition:
pe.exports("CPlApplet")
}
rule is_dll
{
condition:
pe.characteristics & pe.DLL
}
Reference¶
-
machine
¶ Changed in version 3.3.0.
Integer with one of the following values:
-
MACHINE_UNKNOWN
¶
-
MACHINE_AM33
¶
-
MACHINE_AMD64
¶
-
MACHINE_ARM
¶
-
MACHINE_ARMNT
¶
-
MACHINE_ARM64
¶
-
MACHINE_EBC
¶
-
MACHINE_I386
¶
-
MACHINE_IA64
¶
-
MACHINE_M32R
¶
-
MACHINE_MIPS16
¶
-
MACHINE_MIPSFPU
¶
-
MACHINE_MIPSFPU16
¶
-
MACHINE_POWERPC
¶
-
MACHINE_POWERPCFP
¶
-
MACHINE_R4000
¶
-
MACHINE_SH3
¶
-
MACHINE_SH3DSP
¶
-
MACHINE_SH4
¶
-
MACHINE_SH5
¶
-
MACHINE_THUMB
¶
-
MACHINE_WCEMIPSV2
¶
Example: pe.machine == pe.MACHINE_AMD64
-
-
checksum
¶ New in version 3.6.0.
Integer with the "PE checksum" as stored in the OptionalHeader
-
calculate_checksum
¶ New in version 3.6.0.
Function that calculates the "PE checksum"
Example: pe.checksum == pe.calculate_checksum()
-
subsystem
¶ Integer with one of the following values:
-
SUBSYSTEM_UNKNOWN
¶
-
SUBSYSTEM_NATIVE
¶
-
SUBSYSTEM_WINDOWS_GUI
¶
-
SUBSYSTEM_WINDOWS_CUI
¶
-
SUBSYSTEM_OS2_CUI
¶
-
SUBSYSTEM_POSIX_CUI
¶
-
SUBSYSTEM_NATIVE_WINDOWS
¶
-
SUBSYSTEM_WINDOWS_CE_GUI
¶
-
SUBSYSTEM_EFI_APPLICATION
¶
-
SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER
¶
-
SUBSYSTEM_EFI_RUNTIME_DRIVER
¶
-
SUBSYSTEM_XBOX
¶
-
SUBSYSTEM_WINDOWS_BOOT_APPLICATION
¶
Example: pe.subsystem == pe.SUBSYSTEM_NATIVE
-
-
timestamp
¶ PE timestamp.
-
pointer_to_symbol_table
¶ New in version 3.8.0.
Value of IMAGE_FILE_HEADER::PointerToSymbolTable. Used when the PE image has COFF debug info.
-
number_of_symbols
¶ New in version 3.8.0.
Value of IMAGE_FILE_HEADER::NumberOfSymbols. Used when the PE image has COFF debug info.
-
size_of_optional_header
¶ New in version 3.8.0.
Value of IMAGE_FILE_HEADER::SizeOfOptionalHeader. This is real size of the optional header and reflects differences between 32-bit and 64-bit optional header and number of data directories.
-
opthdr_magic
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::Magic.
-
size_of_code
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfCode. This is the sum of raw data sizes in code sections.
-
size_of_initialized_data
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfInitializedData.
-
size_of_uninitialized_data
¶ Value of IMAGE_OPTIONAL_HEADER::SizeOfUninitializedData.
-
entry_point
¶ Entry point raw offset or virtual address depending on whether YARA is scanning a file or process memory respectively. This is equivalent to the deprecated
entrypoint
keyword.
-
base_of_code
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::BaseOfCode.
-
base_of_data
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::BaseOfData. This field only exists in 32-bit PE files.
-
image_base
¶ Image base relative virtual address.
-
section_alignment
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SectionAlignment. When Windows maps a PE image to memory, all raw sizes (including size of header) are aligned up to this value.
-
file_alignment
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::FileAlignment. All raw data sizes of sections in the PE image are aligned to this value.
-
win32_version_value
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::Win32VersionValue.
-
size_of_image
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfImage. This is the total virtual size of header and all sections.
-
size_of_headers
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfHeaders. This is the raw data size of the PE headers including DOS header, file header, optional header and all section headers. When PE is mapped to memory, this value is subject to aligning up to SectionAlignment.
-
characteristics
¶ Bitmap with PE FileHeader characteristics. Individual characteristics can be inspected by performing a bitwise AND operation with the following constants:
-
RELOCS_STRIPPED
¶ Relocation info stripped from file.
-
EXECUTABLE_IMAGE
¶ File is executable (i.e. no unresolved external references).
-
LINE_NUMS_STRIPPED
¶ Line numbers stripped from file.
-
LOCAL_SYMS_STRIPPED
¶ Local symbols stripped from file.
-
AGGRESIVE_WS_TRIM
¶ Aggressively trim working set
-
LARGE_ADDRESS_AWARE
¶ App can handle >2gb addresses
-
BYTES_REVERSED_LO
¶ Bytes of machine word are reversed.
-
MACHINE_32BIT
¶ 32 bit word machine.
-
DEBUG_STRIPPED
¶ Debugging info stripped from file in .DBG file
-
REMOVABLE_RUN_FROM_SWAP
¶ If Image is on removable media, copy and run from the swap file.
-
NET_RUN_FROM_SWAP
¶ If Image is on Net, copy and run from the swap file.
-
SYSTEM
¶ System File.
-
DLL
¶ File is a DLL.
-
UP_SYSTEM_ONLY
¶ File should only be run on a UP machine
-
BYTES_REVERSED_HI
¶ Bytes of machine word are reversed.
Example: pe.characteristics & pe.DLL
-
-
linker_version
¶ An object with two integer attributes, one for each major and minor linker version.
-
major
¶ Major linker version.
-
minor
¶ Minor linker version.
-
-
os_version
¶ An object with two integer attributes, one for each major and minor OS version.
-
major
¶ Major OS version.
-
minor
¶ Minor OS version.
-
-
image_version
¶ An object with two integer attributes, one for each major and minor image version.
-
major
¶ Major image version.
-
minor
¶ Minor image version.
-
-
subsystem_version
¶ An object with two integer attributes, one for each major and minor subsystem version.
-
major
¶ Major subsystem version.
-
minor
¶ Minor subsystem version.
-
-
dll_characteristics
¶ Bitmap with PE OptionalHeader DllCharacteristics. Do not confuse these flags with the PE FileHeader Characteristics. Individual characteristics can be inspected by performing a bitwise AND operation with the following constants:
-
DYNAMIC_BASE
¶ File can be relocated - also marks the file as ASLR compatible
-
FORCE_INTEGRITY
¶
-
NX_COMPAT
¶ Marks the file as DEP compatible
-
NO_ISOLATION
¶
-
NO_SEH
¶ The file does not contain structured exception handlers, this must be set to use SafeSEH
-
NO_BIND
¶
-
WDM_DRIVER
¶ Marks the file as a Windows Driver Model (WDM) device driver.
-
TERMINAL_SERVER_AWARE
¶ Marks the file as terminal server compatible
-
-
size_of_stack_reserve
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfStackReserve. This is the default amount of virtual memory that will be reserved for stack.
-
size_of_stack_commit
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfStackCommit. This is the default amount of virtual memory that will be allocated for stack.
-
size_of_heap_reserve
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfHeapReserve. This is the default amount of virtual memory that will be reserved for main process heap.
-
size_of_heap_commit
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::SizeOfHeapCommit. This is the default amount of virtual memory that will be allocated for main process heap.
-
loader_flags
¶ New in version 3.8.0.
Value of IMAGE_OPTIONAL_HEADER::LoaderFlags.
-
number_of_rva_and_sizes
¶ Value of IMAGE_OPTIONAL_HEADER::NumberOfRvaAndSizes. This is the number of items in the IMAGE_OPTIONAL_HEADER::DataDirectory array.
-
data_directories
¶ New in version 3.8.0.
A zero-based array of data directories. Each data directory contains virtual address and length of the appropriate data directory. Each data directory has the following entries:
-
virtual_address
¶ Relative virtual address (RVA) of the PE data directory. If this is zero, then the data directory is missing. Note that for digital signature, this is the file offset, not RVA.
-
size
¶ Size of the PE data directory, in bytes.
The index for the data directory entry can be one of the following values:
-
IMAGE_DIRECTORY_ENTRY_EXPORT
¶ Data directory for exported functions.
-
IMAGE_DIRECTORY_ENTRY_IMPORT
¶ Data directory for import directory.
-
IMAGE_DIRECTORY_ENTRY_RESOURCE
¶ Data directory for resource section.
-
IMAGE_DIRECTORY_ENTRY_EXCEPTION
¶ Data directory for exception information.
-
IMAGE_DIRECTORY_ENTRY_SECURITY
¶ This is the raw file offset and length of the image digital signature. If the image has no embedded digital signature, this directory will contain zeros.
-
IMAGE_DIRECTORY_ENTRY_BASERELOC
¶ Data directory for image relocation table.
-
IMAGE_DIRECTORY_ENTRY_DEBUG
¶ Data directory for debug information.
-
IMAGE_DIRECTORY_ENTRY_TLS
¶ Data directory for image thread local storage.
-
IMAGE_DIRECTORY_ENTRY_LOAD_CONFIG
¶ Data directory for image load configuration.
-
IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT
¶ Data directory for image bound import table.
-
IMAGE_DIRECTORY_ENTRY_IAT
¶ Data directory for image Import Address Table.
-
IMAGE_DIRECTORY_ENTRY_DELAY_IMPORT
¶ Data directory for Delayed Import Table. Structure of the delayed import table is linker-dependent. Microsoft version of delayed imports is described in the souces "delayimp.h" and "delayimp.cpp", which can be found in MS Visual Studio 2008 CRT sources.
-
IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR
¶ Data directory for .NET headers.
Example: pe.data_directories[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].virtual_address != 0
-
-
number_of_sections
¶ Number of sections in the PE.
-
sections
¶ New in version 3.3.0.
A zero-based array of section objects, one for each section the PE has. Individual sections can be accessed by using the [] operator. Each section object has the following attributes:
-
name
¶ Section name.
-
characteristics
¶ Section characteristics.
-
virtual_address
¶ Section virtual address.
-
virtual_size
¶ Section virtual size.
-
raw_data_offset
¶ Section raw offset.
-
raw_data_size
¶ Section raw size.
-
pointer_to_relocations
¶ New in version 3.8.0.
Value of IMAGE_SECTION_HEADER::PointerToRelocations.
-
pointer_to_line_numbers
¶ New in version 3.8.0.
Value of IMAGE_SECTION_HEADER::PointerToLinenumbers.
-
number_of_relocations
¶ New in version 3.8.0.
Value of IMAGE_SECTION_HEADER::NumberOfRelocations.
-
number_of_line_numbers
¶ New in version 3.8.0.
Value of IMAGE_SECTION_HEADER::NumberOfLineNumbers.
Example: pe.sections[0].name == ".text"
Individual section characteristics can be inspected using a bitwise AND operation with the following constants:
-
SECTION_CNT_CODE
¶
-
SECTION_CNT_INITIALIZED_DATA
¶
-
SECTION_CNT_UNINITIALIZED_DATA
¶
-
SECTION_GPREL
¶
-
SECTION_MEM_16BIT
¶
-
SECTION_LNK_NRELOC_OVFL
¶
-
SECTION_MEM_DISCARDABLE
¶
-
SECTION_MEM_NOT_CACHED
¶
-
SECTION_MEM_NOT_PAGED
¶
-
SECTION_MEM_SHARED
¶
-
SECTION_MEM_EXECUTE
¶
-
SECTION_MEM_READ
¶
-
SECTION_MEM_WRITE
¶
Example: pe.sections[1].characteristics & pe.SECTION_CNT_CODE
-
-
overlay
¶ New in version 3.6.0.
A structure containing the following integer members:
-
offset
¶ Overlay section offset.
-
size
¶ Overlay section size.
Example: uint8(0x0d) at pe.overlay.offset and pe.overlay.size > 1024
-
-
number_of_resources
¶ Number of resources in the PE.
-
resource_timestamp
¶ Resource timestamp. This is stored as an integer.
-
resource_version
¶ An object with two integer attributes, major and minor versions.
-
major
¶ Major resource version.
-
minor
¶ Minor resource version.
-
-
resources
¶ Changed in version 3.3.0.
A zero-based array of resource objects, one for each resource the PE has. Individual resources can be accessed by using the [] operator. Each resource object has the following attributes:
-
offset
¶ Offset for the resource data.
-
length
¶ Length of the resource data.
-
type
¶ Type of the resource (integer).
-
id
¶ ID of the resource (integer).
-
language
¶ Language of the resource (integer).
-
type_string
¶ Type of the resource as a string, if specified.
-
name_string
¶ Name of the resource as a string, if specified.
-
language_string
¶ Language of the resource as a string, if specified.
All resources must have a type, id (name), and language specified. They can be either an integer or string, but never both, for any given level.
Example: pe.resources[0].type == pe.RESOURCE_TYPE_RCDATA
Example: pe.resources[0].name_string == "F\x00I\x00L\x00E\x00"
Resource types can be inspected using the following constants:
-
RESOURCE_TYPE_CURSOR
¶
-
RESOURCE_TYPE_BITMAP
¶
-
RESOURCE_TYPE_ICON
¶
-
RESOURCE_TYPE_MENU
¶
-
RESOURCE_TYPE_DIALOG
¶
-
RESOURCE_TYPE_STRING
¶
-
RESOURCE_TYPE_FONTDIR
¶
-
RESOURCE_TYPE_FONT
¶
-
RESOURCE_TYPE_ACCELERATOR
¶
-
RESOURCE_TYPE_RCDATA
¶
-
RESOURCE_TYPE_MESSAGETABLE
¶
-
RESOURCE_TYPE_GROUP_CURSOR
¶
-
RESOURCE_TYPE_GROUP_ICON
¶
-
RESOURCE_TYPE_VERSION
¶
-
RESOURCE_TYPE_DLGINCLUDE
¶
-
RESOURCE_TYPE_PLUGPLAY
¶
-
RESOURCE_TYPE_VXD
¶
-
RESOURCE_TYPE_ANICURSOR
¶
-
RESOURCE_TYPE_ANIICON
¶
-
RESOURCE_TYPE_HTML
¶
-
RESOURCE_TYPE_MANIFEST
¶
For more information refer to:
http://msdn.microsoft.com/en-us/library/ms648009(v=vs.85).aspx
-
-
version_info
¶ New in version 3.2.0.
Dictionary containing the PE's version information. Typical keys are:
Comments
CompanyName
FileDescription
FileVersion
InternalName
LegalCopyright
LegalTrademarks
OriginalFilename
ProductName
ProductVersion
For more information refer to:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms646987(v=vs.85).aspx
Example: pe.version_info["CompanyName"] contains "Microsoft"
-
number_of_signatures
¶ Number of authenticode signatures in the PE.
-
signatures
¶ A zero-based array of signature objects, one for each authenticode signature in the PE file. Usually PE files have a single signature.
-
thumbprint
¶ New in version 3.8.0.
A string containing the thumbprint of the signature.
-
issuer
¶ A string containing information about the issuer. These are some examples:
"/C=US/ST=Washington/L=Redmond/O=Microsoft Corporation/CN=Microsoft Code Signing PCA" "/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)10/CN=VeriSign Class 3 Code Signing 2010 CA" "/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO Code Signing CA 2"
-
subject
¶ A string containing information about the subject.
-
version
¶ Version number.
-
algorithm
¶ Algorithm used for this signature. Usually "sha1WithRSAEncryption".
-
serial
¶ A string containing the serial number. This is an example:
"52:00:e5:aa:25:56:fc:1a:86:ed:96:c9:d4:4b:33:c7"
-
not_before
¶ Unix timestamp on which the validity period for this signature begins.
-
not_after
¶ Unix timestamp on which the validity period for this signature ends.
-
-
rich_signature
¶ Structure containing information about the PE's rich signature as documented here.
-
offset
¶ Offset where the rich signature starts. It will be undefined if the file doesn't have a rich signature.
-
length
¶ Length of the rich signature, not including the final "Rich" marker.
-
key
¶ Key used to encrypt the data with XOR.
-
raw_data
¶ Raw data as it appears in the file.
-
clear_data
¶ Data after being decrypted by XORing it with the key.
-
version
(version, [toolid])¶ New in version 3.5.0.
Function returning a sum of count values of all matching version records. Provide the optional toolid argument to only match when both match for one entry. More information can be found here:
http://www.ntcore.com/files/richsign.htm
Note: Prior to version 3.11.0, this function returns only a boolean value (0 or 1) if the given version and optional toolid is present in an entry.
Example: pe.rich_signature.version(24215, 261) == 61
-
toolid
(toolid, [version])¶ New in version 3.5.0.
Function returning a sum of count values of all matching toolid records. Provide the optional version argument to only match when both match for one entry. More information can be found here:
http://www.ntcore.com/files/richsign.htm
Note: Prior to version 3.11.0, this function returns only a boolean value (0 or 1) if the given toolid and optional version is present in an entry.
Example: pe.rich_signature.toolid(170, 40219) >= 99
-
-
pdb_path
¶ New in version 4.0.0.
Path of the PDB file for this PE if present.
- Example: pe.pdb_path == "D:\workspace\2018_R9_RelBld\target\checkout\custprof\Release\custprof.pdb"
-
exports
(function_name)¶ Function returning true if the PE exports function_name or false otherwise.
Example: pe.exports("CPlApplet")
-
exports
(ordinal) New in version 3.6.0.
Function returning true if the PE exports ordinal or false otherwise.
Example: pe.exports(72)
-
exports
(/regular_expression/) New in version 3.7.1.
Function returning true if the PE exports regular_expression or false otherwise.
Example: pe.exports(/^AXS@@/)
-
exports_index
(function_name)¶ New in version 4.0.0.
Function returning the index into the export_details array where the named function is, undefined otherwise.
Example: pe.exports_index("CPlApplet")
-
exports_index
(ordinal) New in version 4.0.0.
Function returning the index into the export_details array where the exported ordinal is, undefined otherwise.
Example: pe.exports_index(72)
-
exports_index
(/regular_expression/) New in version 4.0.0.
Function returning the first index into the export_details array where the regular expression matches the exported name, undefined otherwise.
Example: pe.exports_index(/^ERS@@/)
-
number_of_exports
¶ New in version 3.6.0.
Number of exports in the PE.
-
export_details
¶ New in version 4.0.0.
Array of structures containing information about the PE's exports.
-
offset
¶ Offset where the exported function starts.
-
name
¶ Name of the exported function. It will be undefined if the function has no name.
-
forward_name
¶ The name of the function where this export forwards to. It will be undefined if the export is not a forwarding export.
-
ordinal
¶ The ordinal of the exported function, after the ordinal base has been applied to it.
-
-
dll_name
¶ New in version 4.0.0.
The name of the DLL, if it exists in the export directory.
-
export_timestamp
¶ New in version 4.0.0.
The timestamp the export data was created..
-
number_of_imports
¶ New in version 3.6.0.
Number of imports in the PE.
-
imports
(dll_name, function_name)¶ Function returning true if the PE imports function_name from dll_name, or false otherwise. dll_name is case insensitive.
Example: pe.imports("kernel32.dll", "WriteProcessMemory")
-
imports
(dll_name) New in version 3.5.0.
Changed in version 4.0.0.
Function returning the number of functions from the dll_name, in the PE imports. dll_name is case insensitive.
Note: Prior to version 4.0.0, this function returned only a boolean value indicating if the given DLL name was found in the PE imports. This change is backward compatible, as any number larger than 0 also evaluates as true.
Examples: pe.imports("kernel32.dll"), pe.imports("kernel32.dll") == 10
-
imports
(dll_name, ordinal) New in version 3.5.0.
Function returning true if the PE imports ordinal from dll_name, or false otherwise. dll_name is case insensitive.
Example: pe.imports("WS2_32.DLL", 3)
-
imports
(dll_regexp, function_regexp) New in version 3.8.0.
Changed in version 4.0.0.
Function returning the number of functions from the PE imports where a function name matches function_regexp and a DLL name matches dll_regexp. Both dll_regexp and function_regexp are case sensitive unless you use the "/i" modifier in the regexp, as shown in the example below.
Note: Prior to version 4.0.0, this function returned only a boolean value indicating if matching import was found or not. This change is backward compatible, as any number larger than 0 also evaluates as true.
Example: pe.imports(/kernel32.dll/i, /(Read|Write)ProcessMemory/) == 2
-
locale
(locale_identifier)¶ New in version 3.2.0.
Function returning true if the PE has a resource with the specified locale identifier. Locale identifiers are 16-bit integers and can be found here:
http://msdn.microsoft.com/en-us/library/windows/desktop/dd318693(v=vs.85).aspx
Example: pe.locale(0x0419) // Russian (RU)
-
language
(language_identifier)¶ New in version 3.2.0.
Function returning true if the PE has a resource with the specified language identifier. Language identifiers are 8-bit integers and can be found here:
http://msdn.microsoft.com/en-us/library/windows/desktop/dd318693(v=vs.85).aspx
Example: pe.language(0x0A) // Spanish
-
imphash
()¶ New in version 3.2.0.
Function returning the import hash or imphash for the PE. The imphash is a MD5 hash of the PE's import table after some normalization. The imphash for a PE can be also computed with pefile and you can find more information in Mandiant's blog.
Example: pe.imphash() == "b8bb385806b89680e13fc0cf24f4431e"
-
section_index
(name)¶ Function returning the index into the sections array for the section that has name. name is case sensitive.
Example: pe.section_index(".TEXT")
-
section_index
(addr) New in version 3.3.0.
Function returning the index into the sections array for the section that has addr. addr can be an offset into the file or a memory address.
Example: pe.section_index(pe.entry_point)
-
is_dll
()¶ New in version 3.5.0.
Function returning true if the PE is a DLL.
Example: pe.is_dll()
-
is_32bit
()¶ New in version 3.5.0.
Function returning true if the PE is 32bits.
Example: pe.is_32bit()
-
is_64bit
()¶ New in version 3.5.0.
Function returning true if the PE is 64bits.
Example: pe.is_64bit()
-
rva_to_offset
(addr)¶ New in version 3.6.0.
Function returning the file offset for RVA addr. Be careful to pass relative addresses here and not absolute addresses, like pe.entry_point when scanning a process.
Example: pe.rva_to_offset(pe.sections[0].virtual_address) == pe.sections[0].raw_data_offset
This example will make sure the offset for the virtual address in the first section equals the file offset for that section.