Octopus

Huge thanks to QuoScient for having sponsored this project.

Octopus is a security analysis framework for WebAssembly module and Blockchain Smart Contract.

The purpose of Octopus is to provide an easy way to analyze closed-source WebAssembly module and smart contracts bytecode to understand deeper their internal behaviours.

Features

Explorer: Octopus JSON-RPC client implementation to communicate with blockchain platforms
Disassembler: Octopus can translate bytecode into assembly representation
Control Flow Analysis: Octopus can generate a Control Flow Graph (CFG)
Call Flow Analysis: Octopus can generate a Call Flow Graph (function level)
IR conversion (SSA): Octopus can simplify assembly into Static Single Assignment (SSA) representation
Symbolic Execution: Octopus use symbolic execution to find new paths into a program

Platforms / Architectures

Octopus support the following types of programs/smart contracts:

WebAssembly module (WASM)
Bitcoin script (BTC script)
Ethereum smart contracts (EVM bytecode & Ewasm)
EOS smart contracts (WASM)
NEO smart contracts (AVM bytecode)

	BTC	ETH (EVM)	ETH (WASM)	EOS	NEO	WASM
Explorer	✔️	✔️	✔️	✔️	✔️	⭕
Disassembler	✔️	✔️	✔️	✔️	✔️	✔️
Control Flow Analysis	✖️	✔️	✔️	✔️	✔️	✔️
Call Flow Analysis	✖️	➕	✔️	✔️	➕	✔️
IR conversion (SSA)	✖️	✔️	➕	➕	✖️	✔️
Symbolic Execution	✖️	➕	➕	➕	✖️	➕

PyPI package ✔️
Docker ✔️

✔️ DONE / :heavy_plus_sign: WIP / :heavy_multiplication_x: TODO / :o: N/A

Requirements

Octopus is supported on Linux (ideally Ubuntu 16.04) and requires Python >=3.5 (ideally 3.6).

Dependencies:

Graph generation: graphviz
Explorer: requests
Symbolic Execution: z3-solver
Wasm: wasm

Quick Start

Install system dependencies

# Install system dependencies
sudo apt-get update && sudo apt-get install python-pip graphviz xdg-utils -y

Install Octopus:

# Download Octopus
git clone https://github.com/pventuzelo/octopus
cd octopus

# Install Octopus library/CLI and its dependencies
python3 setup.py install

or

# but prefer the first way to install if possible
pip3 install octopus

Run tests

# Run tests for all platforms (disassembly, CFG, ...)
./run_tests.sh
# Run tests that require internet access (explorer tests)
./run_explorer_tests.sh

# Run tests for only one platforms
# {btc, eth, eos, neo, wasm}_run_tests.sh
cd octopus/tests/
./wasm_run_tests.sh

Docker container

A docker container providing the toolset is available at docker hub. In a terminal, run the following commands:

docker pull smartbugs/octopus
docker run -it smartbugs/octopus
cd octopus
python3 octopus_eth_evm.py -s -f examples/ETH/evm_bytecode/61EDCDf5bb737ADffE5043706e7C5bb1f1a56eEA.bytecode

Command-line tools

WebAssembly: octopus_wasm.py
Ethereum (EVM): octopus_eth_evm.py

In-depth Examples using APIs

WebAssembly

Disassembler

Disassembly of a Wasm module:

from octopus.arch.wasm.disassembler import WasmDisassembler

FILE = "examples/wasm/samples/helloworld.wasm"

with open(FILE, 'rb') as f:
    module_bytecode = f.read()

disasm = WasmDisassembler()
# return list of functions instructions (list)
print(disasm.disassemble_module(module_bytecode))
#[[<octopus.arch.wasm.instruction.WasmInstruction at 0x7f85e4904278>,<octopus.arch.wasm.instruction.WasmInstruction at 0x7f85e4904f60>,<octopus.arch.wasm.instruction.WasmInstruction at 0x7f85e4904ef0>]]

print()
# return text of functions code
print(disasm.disassemble_module(module_bytecode, r_format='text'))
# func 0
# i32.const 0
# call 0
# end

Disassembly of wasm bytecode:

from octopus.arch.wasm.disassembler import WasmDisassembler

# bytecode in WebAssembly is the function code (i.e. function body)
bytecode = b'\x02\x7fA\x18\x10\x1cA\x00\x0f\x0b'
# create a WasmDisassembler object
disasm = WasmDisassembler(bytecode)

# disassemble bytecode into a list of WasmInstruction
# attributes r_format='list' by default
print(disasm.disassemble())

#[<octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904eb8>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904278>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904390>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904ef0>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904f60>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4901048>]
print()
print(disasm.disassemble(r_format='reverse'))

#{0: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4901048>, 1: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904240>, 2: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904f60>, 3: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904ef0>, 4: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904278>, 5: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904390>}
print()
print(disasm.disassemble(r_format='text'))
# block -1
# i32.const 24
# call 28
# i32.const 0
# return
# end

ModuleAnalyzer

from octopus.arch.wasm.analyzer import WasmModuleAnalyzer

FILE = "examples/wasm/samples/hello_wasm_studio.wasm"

with open(FILE, 'rb') as f:
    module_bytecode = f.read()

# return list of functions instructions (list)
# attributes analysis=True by default
analyzer = WasmModuleAnalyzer(module_bytecode)

# show analyzer attributes
print(analyzer.func_prototypes)
# [('putc_js', 'i32', ''),
#  ('__syscall0', 'i32', 'i32'),
#  ('__syscall3', 'i32 i32 i32 i32', 'i32'),
#  ('__syscall1', 'i32 i32', 'i32'),
#  ('__syscall5', 'i32 i32 i32 i32 i32 i32', 'i32'),
#  ('__syscall4', 'i32 i32 i32 i32 i32', 'i32'),
#  ('$func6', '', ''),
#  ('main', '', 'i32'),
#  ('writev_c', 'i32 i32 i32', 'i32'),
#  ('$func9', '', 'i32'),
#  ('$func10', 'i32', 'i32'),
#  ('$func11', 'i32', 'i32'),
#  ('$func12', 'i32', ''),
#  ('$func13', 'i32', 'i32'),
#  ('$func14', 'i32 i32 i32 i32', 'i32'),
#  ('$func15', 'i32 i32', 'i32'),
#  ('$func16', 'i32 i32', 'i32'),
#  ('$func17', 'i32', 'i32'),
#  ('$func18', 'i32', 'i32'),
#  ('$func19', 'i32', 'i32'),
#  ('$func20', 'i32 i32 i32', 'i32'),
#  ('$func21', 'i32 i32 i32', 'i32'),
#  ('$func22', 'i32 i64 i32', 'i64'),
#  ('$func23', 'i32 i32 i32', 'i32'),
#  ('$func24', 'i32', 'i32'),
#  ('$func25', 'i32 i32 i32 i32', '')]
print()
print(analyzer.contains_emscripten_syscalls())
#[('__syscall0', 'restart_syscall'),
# ('__syscall3', 'read'),
# ('__syscall1', 'exit'),
# ('__syscall5', 'open'),
# ('__syscall4', 'write')]

Control Flow Analysis

from octopus.arch.wasm.cfg import WasmCFG

# complete wasm module
file_name = "examples/wasm/samples/fib.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# create the cfg
cfg = WasmCFG(raw)

# visualize CFGGraph 
# generate graph.dot and graph.pdf file
cfg.visualize()

Functions' instructions analytics

from octopus.arch.wasm.cfg import WasmCFG

# complete wasm module
file_name = "examples/wasm/samples/hello_wasm_studio.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# create the cfg
cfg = WasmCFG(raw)

# visualization
cfg.visualize_instrs_per_funcs()

Call Flow Analysis

from octopus.arch.wasm.cfg import WasmCFG

# fibonacci wasm module
file_name = "examples/wasm/samples/hello_wasm_studio.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# create the cfg
cfg = WasmCFG(raw)

# visualize Call Flow Graph
# generate call_graph.dot and call_graph.pdf file
# 
# color similar to https://webassembly.studio/
# imported func == turquoise / exported func == grey
# edge label = number of different calls to the function
cfg.visualize_call_flow()

Legend:

IR conversion (SSA)

from octopus.arch.wasm.emulator import WasmSSAEmulatorEngine

# complete wasm module
file_name = "examples/wasm/samples/fib.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()


# run the emulator for SSA
emul = WasmSSAEmulatorEngine(raw)
emul.emulate_one_function('fib')
# or emul.emulate_functions(['fib'])
# or emul.emulate_functions() # emulate all the function

# visualization of the cfg with SSA
emul.cfg.visualize(ssa=True)

Ethereum (ETH) - EVM

Explorer

from octopus.platforms.ETH.explorer import EthereumInfuraExplorer
from octopus.platforms.ETH.explorer import INFURA_ROPSTEN

KEY_API = "bHuaQhX91nkQBac8Wtgj"
# connection to ROPSTEN network (testnet)
explorer = EthereumInfuraExplorer(KEY_API, network=INFURA_ROPSTEN)

# connection to MAINNET network (mainnet)
# explorer = EthereumInfuraExplorer(KEY_API)

# Test ROPSTEN network current block number
block_number = explorer.eth_blockNumber()
print(block_number)
# 3675552

# Retrieve code of this smart contract
addr = "0x3c6B10a5239B1a8A27398583F49771485382818F"
code = explorer.eth_getCode(addr)
print(code)
# 0x6060604052600436106049576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff16806360fe47b114604e5780636d4ce63c14606e575b600080fd5b3415605857600080fd5b606c60048080359060200190919050506094565b005b3415607857600080fd5b607e609e565b6040518082815260200191505060405180910390f35b8060008190555050565b600080549050905600a165627a7a72305820e1f98c821c12eea52047d7324b034ddccc41eaa7365d369b34580ab73c71a8940029

Disassembler

from octopus.platforms.ETH.disassembler import EthereumDisassembler

# smart contract bytecode
bytecode_hex = "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"

disasm = EthereumDisassembler()
disasm.disassemble(bytecode_hex)

# disassemble bytecode into a list of EthereumInstruction
# attributes r_format='list' by default
print(disasm.disassemble(bytecode_hex))

#[<octopus.platforms.ETH.instruction.EthereumInstruction object at 0x7f85d4add5c0>, <octopus.platforms.ETH.instruction.EthereumInstruction object at 0x7f85d4ad8588>, <octopus.platforms.ETH.instruction.EthereumInstruction object at 0x7f85d4ad8c50>]

print()
print(disasm.disassemble(bytecode_hex, r_format='reverse'))

# {0: <octopus.platforms.ETH.instruction.EthereumInstruction object at 0x7f85d4ad8160>, ..., 229: <octopus.platforms.ETH.instruction.EthereumInstruction object at 0x7f85d4ad8630>, 230: <octopus.platforms.ETH.instruction.EthereumInstruction object at 0x7f85d4ad87b8>}

print()
print(disasm.disassemble(bytecode_hex,r_format='text'))
# PUSH1 0x60
# PUSH1 0x40
# MSTORE
# PUSH1 0x0
# CALLDATALOAD
# PUSH29 0x100000000000000000000000000000000000000000000000000000000
# SWAP1
# DIV
# DUP1
# PUSH4 0x5fd8c710
# EQ
# PUSH2 0x4f
# JUMPI
# ...
# SWAP2
# SWAP1
# POP
# JUMP

Control Flow Analysis

from octopus.analysis.graph import CFGGraph
from octopus.platforms.ETH.cfg import EthereumCFG

# ethernaut0 bytecode
file_name = "examples/ETH/evm_bytecode/Zeppelin_Hello_ethernaut0.bytecode"

# read file
with open(file_name) as f:
    bytecode_hex = f.read()

# create the CFG
cfg = EthereumCFG(bytecode_hex)


# generic visualization api
# generate graph.dot and graph.pdf file
graph = CFGGraph(cfg)
graph.view()
# or directly using the cfg binding
# cfg.visualize()
# and you can get a simplify cfg representation using
# cfg.visualize(simplify=True) or graph.view(simplify=True)

IR conversion (SSA)

# The conversion to SSA is already done by the SSAEmulator
# when the CFG is reconstruct
# by default you have just to visualize it
from octopus.platforms.ETH.cfg import EthereumCFG

# ethernaut0 bytecode
file_name = "examples/ETH/evm_bytecode/Zeppelin_Hello_ethernaut0.bytecode"

# read file
with open(file_name) as f:
    bytecode_hex = f.read()

# create the CFG
cfg = EthereumCFG(bytecode_hex)

# SSA visualization
cfg.visualize(ssa=True)

Ethereum (WASM)

Explorer

from octopus.platforms.ETH.explorer import EthereumInfuraExplorer
from octopus.platforms.ETH.explorer import INFURA_KOVAN

# connection to ROPSTEN network (testnet)
explorer = EthereumInfuraExplorer("bHuaQhX91nkQBac8Wtgj",
                                  network=INFURA_KOVAN)
# connection to MAINNET network (mainnet)
# explorer = EthereumInfuraExplorer("bHuaQhX91nkQBac8Wtgj")

# test infura access
block_number = explorer.eth_blockNumber()
print('blockNumber = %d' % block_number)

# retrieve code of this smart contract
addr = "0x1120e596b173d953ba52ce262f73ce3734b0e40e"
code = explorer.eth_getCode(addr)
print()
print(code)
# blockNumber = 8803487
# 
# 0x0061736d0100000001090260000060027f7f00021a0203656e7603726574000103656e76066d656d6f7279020102100303020000040501700101010501000601000708010463616c6c00010a120205001002000b0a00418008410b1000000b0b1201004180080b0b48656c6c6f20776f726c64000b076c696e6b696e6703010b0066046e616d65015f060003726574010570616e6963020463616c6c032f5f5a4e3134707761736d5f657468657265756d3365787433726574313768363034643830393864313638366338304504066465706c6f790511727573745f626567696e5f756e77696e64

Disassembler

Disassembly of a Wasm module:

from octopus.platforms.ETH.disassembler import EthereumDisassembler

FILE = "examples/ETH/wasm/helloworld_kovan.bytecode"

with open(FILE, 'r') as f:
    module_bytecode = f.read()

disasm = EthereumDisassembler(arch='wasm')
# return list of functions instructions (list)
print(disasm.disassemble_module(module_bytecode))
#[[<octopus.arch.wasm.instruction.WasmInstruction object at 0x7efc0ceaa898>], [<octopus.arch.wasm.instruction.WasmInstruction object at 0x7efc0ceaa7b8>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7efc0ceaa780>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7efc0ceaa748>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7efc0ceaa6d8>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7efc0ceaa710>]]

print()
# return text of functions code
print(disasm.disassemble_module(module_bytecode, r_format='text'))
# func 0
# end
# 
# func 1
# call 1
# i32.const 1036
# i32.const 232
# call 0
# end

Disassembly of wasm bytecode:

from octopus.platforms.ETH.disassembler import EthereumDisassembler

# bytecode in WebAssembly is the function code (i.e. function body)
bytecode = b'\x02\x7fA\x18\x10\x1cA\x00\x0f\x0b'
# create a WasmDisassembler object
disasm = EthereumDisassembler(bytecode, arch='wasm')

# disassemble bytecode into a list of WasmInstruction
# attributes r_format='list' by default
print(disasm.disassemble())

#[<octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904eb8>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904278>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904390>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904ef0>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904f60>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4901048>]
print()
print(disasm.disassemble(r_format='reverse'))

#{0: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4901048>, 1: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904240>, 2: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904f60>, 3: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904ef0>, 4: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904278>, 5: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904390>}
print()
print(disasm.disassemble(r_format='text'))
# block -1
# i32.const 24
# call 28
# i32.const 0
# return
# end

ModuleAnalyzer

from octopus.arch.wasm.analyzer import WasmModuleAnalyzer

FILE = "examples/ETH/wasm/helloworld_kovan.bytecode"

with open(FILE, 'r') as f:
    module_bytecode = f.read()

# return list of functions instructions (list)
# attributes analysis=True by default
analyzer = WasmModuleAnalyzer(module_bytecode)

# show analyzer attributes
print(analyzer.func_prototypes)
# [('ret', 'i32 i32', '', 'import'), ('$func1', '', '', 'local'), ('call', '', '', 'export')]
print()
print(analyzer.exports)
# [{'field_str': 'call', 'kind': 0, 'index': 2}]
print()
print(analyzer.imports_func)
# [('env', 'ret', 1)]
print()
print(analyzer.datas)
# [{'data': b'Hello world', 'index': 0, 'offset': None, 'size': 11},
# {'data': b'\x00asm\x01\x00\x00\x00\x01\t\x02`\x00\x00`\x02\x7f\x7f\x00\x02\x1a\x02\x03env\x03ret\x00\x01\x03env\x06memory\x02\x01\x02\x10\x03\x03\x02\x00\x00\x04\x05\x01p\x01\x01\x01\x05\x01\x00\x06\x01\x00\x07\x08\x01\x04call\x00\x01\n\x12\x02\x05\x00\x10\x02\x00\x0b\n\x00A\x80\x08A\x0b\x10\x00\x00\x0b\x0b\x12\x01\x00A\x80\x08\x0b\x0bHello world\x00\x0b\x07linking\x03\x01\x0b\x00f\x04name\x01_\x06\x00\x03ret\x01\x05panic\x02\x04call\x03/_ZN14pwasm_ethereum3ext3ret17h604d8098d1686c80E\x04\x06deploy\x05\x11rust_begin_unwind',
# 'index': 0,
# 'offset': None,
# 'size': 232}]

Control Flow Analysis

from octopus.platforms.ETH.cfg import EthereumCFG

# HelloWorld on Kovan Parity Network
file_name = "examples/ETH/wasm/helloworld_kovan.bytecode"

# read file
with open(file_name) as f:
    bytecode_hex = f.read()

# create the CFG
cfg = EthereumCFG(bytecode_hex, arch='wasm')
cfg.visualize()

Functions' instructions analytics

from octopus.platforms.ETH.cfg import EthereumCFG

# HelloWorld on Kovan Parity Network
file_name = "examples/ETH/wasm/helloworld_kovan.bytecode"

# read file
with open(file_name) as f:
    bytecode_hex = f.read()

# create the CFG
cfg = EthereumCFG(bytecode_hex, arch='wasm')

# visualization
cfg.visualize_instrs_per_funcs()

Call Flow Analysis

from octopus.platforms.ETH.cfg import EthereumCFG

# HelloWorld on Kovan Parity Network
file_name = "examples/ETH/wasm/helloworld_kovan.bytecode"

# read file
with open(file_name) as f:
    bytecode_hex = f.read()

# create the CFG
cfg = EthereumCFG(bytecode_hex, arch='wasm')

# visualization
cfg.visualize_call_flow()

Legend:

IR conversion (SSA)

# TODO

NEO

Explorer

from octopus.platforms.NEO.explorer import NeoExplorerRPC

# get list nodes here: http://monitor.cityofzion.io/
explorer = NeoExplorerRPC(host='seed2.neo.org')

# get current number of block on the blockchain
print(explorer.getblockcount())
# 2534868

# get information on a contract
# lock smart contract address: d3cce84d0800172d09c88ccad61130611bd047a4
contract = explorer.getcontractstate("d3cce84d0800172d09c88ccad61130611bd047a4")
print(contract)
# {'author': 'Erik Zhang',
# 'code_version': '2.0',
# 'description': 'Lock 2.0',
# 'email': '[email protected]',
# 'hash': '0xd3cce84d0800172d09c88ccad61130611bd047a4',
# 'name': 'Lock',
# 'parameters': ['Integer', 'PublicKey', 'Signature'],
# 'properties': {'dynamic_invoke': False, 'storage': False},
# 'returntype': 'Boolean',
# 'script': '56c56b6c766b00527ac46c766b51527ac46c766b52527ac4616168184e656f2e426c6f636b636861696e2e4765744865696768746168184e656f2e426c6f636b636861696e2e4765744865616465726c766b53527ac46c766b00c36c766b53c36168174e656f2e4865616465722e47657454696d657374616d70a06c766b54527ac46c766b54c3640e00006c766b55527ac4621a006c766b51c36c766b52c3617cac6c766b55527ac46203006c766b55c3616c7566',
# 'version': 0}

# smart contract code in contract['script']
print(contract['script'])

Disassembler

from octopus.platforms.NEO.disassembler import NeoDisassembler

# lock contract
file_name = "examples/NEO/samples/Lock.bytecode"

# read file
with open(file_name) as f:
    bytecode = f.read()

disasm = NeoDisassembler()

print(disasm.disassemble(bytecode, r_format='text'))
# PUSH6
# NEWARRAY
# TOALTSTACK
# FROMALTSTACK
# DUP
# TOALTSTACK
# PUSH0
# PUSH2
# ROLL
# SETITEM
# FROMALTSTACK
# ....
# PICKITEM
# NOP
# FROMALTSTACK
# DROP
# RET

Control Flow Analysis

from octopus.analysis.graph import CFGGraph
from octopus.platforms.NEO.cfg import NeoCFG

# lock contract
file_name = "examples/NEO/samples/Lock.bytecode"

# read file
with open(file_name) as f:
    raw = f.read()

# create neo cfg - automatic static analysis
cfg = NeoCFG(raw)

# graph visualization
graph = CFGGraph(cfg, filename="Lock_cfg")
graph.view_functions()

EOS

Explorer

from octopus.platforms.EOS.explorer import EosExplorer

host = "api.cypherglass.com"

# by defaul the port is 8888
explo = EosExplorer(host=host)

# get info about the node
explo.get_info()

'''
{'block_cpu_limit': 180289,
 'block_net_limit': 1045680,
 'chain_id': 'aca376f206b8fc25a6ed44dbdc66547c36c6c33e3a119ffbeaef943642f0e906',
 'head_block_id': '018d6e2bcf6295126cd74cf694b5cca3529eefc42b334b394ef87c3a43876739',
 'head_block_num': 26045995,
 'head_block_producer': 'eosswedenorg',
 'head_block_time': '2018-11-09T14:11:29.500',
 'last_irreversible_block_id': '018d6cdcff78bbd9f25c605b02fb67c47a337ece78ddcf73089cee4bf6a410ee',
 'last_irreversible_block_num': 26045660,
 'server_version': 'c71d2245',
 'server_version_string': 'mainnet-1.3.0',
 'virtual_block_cpu_limit': 38092879,
 'virtual_block_net_limit': 1048576000}
'''
explo.get_block(1337)

'''
{'action_mroot': 'bcb9763baa3bbf98ed36379b4be0ecb2d9cd21c75df01729c63b2b021001c10c',
 'block_extensions': [],
 'block_num': 1337,
 'confirmed': 0,
 'header_extensions': [],
 'id': '00000539d17a03af7126e073be4c4d99a72b7f58793cf2c87b9bfd41b6c711fb',
 'new_producers': None,
 'previous': '00000538b374c1cbfaeed7253ad3075ddc72a28f0a0515301fc1bbed675f2316',
 'producer': 'eosio',
 'producer_signature': 'SIG_K1_K5jWf36t6j454Hb2fGuV37YTwMTvuQ51ZPBtpru8Ud2axtMTEauWyvtpJuTpnvqzReUndDgEDXvoeEP4jdj2bpnYKBt6g2',
 'ref_block_prefix': 1944069745,
 'schedule_version': 0,
 'timestamp': '2018-06-09T12:09:21.500',
 'transaction_mroot': '0000000000000000000000000000000000000000000000000000000000000000',
 'transactions': []}
'''

Disassembler

from octopus.platforms.EOS.disassembler import EosDisassembler

# complete wasm module
file_name = "examples/EOS/samples/eos_ping.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# just disassembly
disasm = EosDisassembler()

# because we provide full module bytecode
# we need to use disassemble_module()
# otherwise just disassemble() is enough
text = disasm.disassemble_module(raw, r_format="text")
print(text)
# func 0
# get_local 0
# get_local 1
# i32.const 32
# call 12
# i32.eqz
# end
# 
# func 1
# get_local 0
# i64.load 3, 0
# get_local 0
# i64.load 3, 8
# call 6
# end
# 
# func 2
# ...
# end
# 
# ...

ModuleAnalyzer

from octopus.platforms.EOS.analyzer import EosAnalyzer

# complete wasm module
file_name = "examples/EOS/samples/eos_ping.wasm"

with open(file_name, 'rb') as f:
    module_bytecode = f.read()

# return list of functions instructions (list)
# attributes analysis=True by default
analyzer = EosAnalyzer(module_bytecode)

# show analyzer attributes
print(analyzer.func_prototypes)
#[('action_data_size', '', 'i32', 'import'), ('eosio_assert', 'i32 i32', '', 'import'), ('eosio_exit', 'i32', '', 'import'), ('memcpy', 'i32 i32 i32', 'i32', 'import'), ('prints', 'i32', '', 'import'), ('read_action_data', 'i32 i32', 'i32', 'import'), ('require_auth2', 'i64 i64', '', 'import'), ('_ZeqRK11checksum256S1_', 'i32 i32', 'i32', 'export'), ('_ZN5eosio12require_authERKNS_16permission_levelE', 'i32', '', 'export'), ('apply', 'i64 i64 i64', '', 'export'), ('$func10', 'i32 i64', '', 'local'), ('$func11', 'i32 i32', 'i32', 'local'), ('memcmp', 'i32 i32 i32', 'i32', 'export'), ('malloc', 'i32', 'i32', 'export'), ('$func14', 'i32 i32', 'i32', 'local'), ('$func15', 'i32', 'i32', 'local'), ('free', 'i32', '', 'export'), ('$func17', '', '', 'local')]
print()
print(analyzer.exports)
# [{'field_str': 'memory', 'kind': 2, 'index': 0}, {'field_str': '_ZeqRK11checksum256S1_', 'kind': 0, 'index': 7}, {'field_str': '_ZN5eosio12require_authERKNS_16permission_levelE', 'kind': 0, 'index': 8}, {'field_str': 'apply', 'kind': 0, 'index': 9}, {'field_str': 'memcmp', 'kind': 0, 'index': 12}, {'field_str': 'malloc', 'kind': 0, 'index': 13}, {'field_str': 'free', 'kind': 0, 'index': 16}]
print()
print(analyzer.imports_func)
# [('env', 'action_data_size', 3), ('env', 'eosio_assert', 5), ('env', 'eosio_exit', 2), ('env', 'memcpy', 6), ('env', 'prints', 2), ('env', 'read_action_data', 4), ('env', 'require_auth2', 1)]

Control Flow Analysis

from octopus.platforms.EOS.cfg import EosCFG
from octopus.analysis.graph import CFGGraph

# complete wasm module
file_name = "examples/EOS/samples/eos_ping.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# create the cfg
cfg = EosCFG(raw)

# visualize
graph = CFGGraph(cfg)
graph.view_functions()

Call Flow Analysis

from octopus.platforms.EOS.cfg import EosCFG

# complete wasm module
file_name = "examples/EOS/samples/eos_ping.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# create the cfg
cfg = EosCFG(raw)

# visualize
cfg.visualize_call_flow()

Functions' instructions analytics

from octopus.platforms.EOS.cfg import EosCFG

# complete wasm module
file_name = "examples/EOS/samples/eos_ping.wasm"

# read file
with open(file_name, 'rb') as f:
    raw = f.read()

# create the cfg
cfg = EosCFG(raw)

# visualize
cfg.visualize_instrs_per_funcs()

Bitcoin

Explorer

from octopus.platforms.BTC.explorer import BitcoinExplorerRPC

RPC_USER = 'test'
RPC_PASSWORD = 'test'
RPC_HOST = 'localhost'

host = '%s:%s@%s' % (RPC_USER, RPC_PASSWORD, RPC_HOST)

explorer = BitcoinExplorerRPC(host)

explorer.getbestblockhash()
# '00000000000000000012085cfe8c79bcdacf81fbd82f6ab52c3cb3a454d4987c'

explorer.getblockcount()
#550859

Disassembler

from octopus.platforms.BTC.disassembler import BitcoinDisassembler

# Witness Script
file_name = "examples/BTC/witness_script.hex"

# read file
with open(file_name) as f:
    bytecode = f.read()

disasm = BitcoinDisassembler()

print(disasm.disassemble(bytecode, r_format='text'))
# 0
# OP_ROT
# OP_ROT
# 2
# 0203f4d01d0b35588638631ebb7d46d8387fd1aeb3dbecfdd3faf7c056b023c833
# 03aa6677e3ce1bd634f4f2e1cd60a60af002e1b30484d4d1611b183b16d391ee96
# 03bf164811abb8c91ed39e58d4e307f86cb4e487c83f727a2c482bc71a0f96f1db
# 3
# OP_CHECKMULTISIG

Please find examples in examples folder.

Publications and Videos

BLACKALPS 2018 Reversing and Vulnerability research of Ethereum Smart Contracts
Devcon iv. Reversing Ethereum Smart Contracts to find out what's behind EVM bytecode
hack.lu 2018 Reversing and Vulnerability research of Ethereum Smart Contracts
ToorCon XX - 2018 Reversing Ethereum Smart Contracts (Introduction)
ToorCon XX - 2018 Dissection of WebAssembly module
REcon Montreal 2018: Reverse Engineering Of Blockchain Smart Contracts

Authors

Patrick Ventuzelo - Creator - @Pat_Ventuzelo

See also the list of contributors who participated in this project.

License

This project is licensed under the MIT License - see the LICENSE file for details

Acknowledgments

Sponsor:

QuoScient

Inspired by:

Trainings & Contact

Patrick Ventuzelo - @pat_ventuzelo

Independent Security Researcher / Trainer.
FREE online courses: here

Name		Name	Last commit message	Last commit date
Latest commit History 237 Commits
.github		.github
docker		docker
examples		examples
images		images
octopus		octopus
.gitignore		.gitignore
LICENSE		LICENSE
README.md		README.md
octopus_eth_evm.py		octopus_eth_evm.py
octopus_wasm.py		octopus_wasm.py
requirements.txt		requirements.txt
run_explorer_tests.sh		run_explorer_tests.sh
run_tests.sh		run_tests.sh
setup.py		setup.py

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