teEther

Quickstart

The start point for analysis is combined_call_exploit.py You invoke it as

python combined_call_exploit.py <contract-code-file> <attacker address> <target-amount>

where * <contract-code-file> is a hex-encoded contract * <attacker address> is the address assumed under attack control * <target-amount> is a specification of how many wei to leak. It can take three forms + +1000 for "at least 1000 wei" (default) + =1000 for "exactly 1000 wei" + -1000 for "at most 1000 wei"

Repository Structure

ethanalyze

Contains the teEther core: * cfg.py: control flow graph representation * cfg_back_traversal.py: backwards taint tracking * constraints.py: constraint solving and utility functions * diassembly.py: raw bytecode disassembly * evm.py: contains two VMs, one for concrete execution (run), and one for symbolic execution (run_symbolic) * explorer.py: Forwards CFG exploration * frontierset.py: Special data-structure to handle dependent edges during CFG traversal * intrange.py: Representation of integer ranges, including boolean functions on integer ranges * memory.py: Abstraction for symbolic memory * opcodes.py: EVM opcode definitions * project.py: Main interface to teEther * slicing.py: backwards slicing * utils.py: utility functions * z3_extra_utils.py: Z3 specific utility functions

unittests

Unittests. Requires test repository.

Main directory

A bunch of scripts. Most notably: * asm.py: Small assembler. Converts .asm files to bytecode * combined_call_exploit.py: multistate exploits * extract_contract_code.py: Extract final contract code from constructor code (as given by solc --bin) * plot_cfg.py: Generate .dot graphs from bytecode * sig.py: Compute 4 byte signature from Solidity function signature

#R: Most of the changes are in combined_exploit.call; nonetheless I'd say that it follows the same general logic I had to also adjust evm.py and some of the constraints.py stuff - but most of it for debugging purposes

exploit_all_addr.py will run combined_call_exploit.py on a range of addresses using the ...Xa = callee ...Xb = CALLER scheme

    python exploit_all_addr.py 0 15

I usually trun debugging off to see only the model and exploits at the end of the contract run it will also run with the "execute_exploit=True" that will send exploit transactions using the client

You can also run combined_call_exploit on specififc addr;

    python combined_call_exploit.py 0x400000000000000000000000000000000000000b 0x3cc7c038f7eea1b70014b788b821d675b13b8760 +1

I've deactiavted the option to use a contract.code file for the time being - it's simply commented out

Finally you can check the results using a terminal in teether-localhost with

    geth --exec 'loadScript("showBalance.js");getBalanceFrom("0x400000000000000000000000000000000000000b", 16)' attach http://127.0.0.1:8545

If on the otherhand you want to run it using the JSON project-exploit way;

    pyhon combined_call_exploit.py ../teether-test/eval/JSON/0_R.contract.code 0x3cc7c038f7eea1b70014b788b821d675b13b8760 +1

and then

    python replay_exploit.py ../teether-test/eval/JSON/0_R.contract.code.project.json ../teether-test/eval/JSON/0_R.contract.code.exploit.json 0x3cc7c038f7eea1b70014b788b821d675b13b8760 +1