Workshop big update based on feedback from day 1

README.md

@@ -5,9 +5,15 @@ Workshop for "web3" bridge hacking at Hacktivity 2022
 
 #### Introduction
 - Web3 vs web2 hacking, concepts / workshop topology
+- Who interacted with dApps/SCs before? 
+- Who codes Solidity?
+- Who codes Rust?
+- Who used a bridge before?
+- Who is the cryptographer?
 
 #### Environment setup, system requirements
 - Any browser for Ethereum, Remix
+- Python3
 - Substrate, Rust nightly
 
 #### Scenario 1: Token on two chains, mint using receipt
@@ -19,8 +25,9 @@ Workshop for "web3" bridge hacking at Hacktivity 2022
 #### Scenario 2: Signature forgery (any chain)
 - Deploy SC on Ethereum chain
 - Compile Substrate with EVM
-- Deploy SC
+- Deploy SC on Substrate chain (so it is different from core)
 - Test ECDSA signature forgery exploit from one to other
+- Test same issue with WASM/ink!
 
 ## Resources
 
@@ -32,6 +39,7 @@ https://ethereum.org/en/developers/docs/standards/tokens/erc-20/
 https://git.hsbp.org/six/eth_keygen
 
 #### Scenario 2
+https://cryptoctf.org/2022/09/11/writeup-of-flag-submission-forgery-by-si/
 https://github.com/paritytech/substrate-contracts-node
 https://docs.substrate.io/quick-start/
 https://github.com/substrate-developer-hub/substrate-front-end-template
@@ -39,4 +47,18 @@ https://github.com/paritytech/ink
 https://github.com/paritytech/substrate/blob/master/primitives/core/src/ecdsa.rs
 https://use.ink/getting-started/setup
 https://medium.com/block-journal/introducing-substrate-smart-contracts-with-ink-d486289e2b59
+https://github.com/paritytech/contracts-ui
+https://contracts-ui.substrate.io/?rpc=wss://rpc.shibuya.astar.network
 https://substrate.io/developers/playground/
+https://security.stackexchange.com/questions/200682/is-it-possible-to-fake-ecdsa-signatures
+
+
+## Solidity Hacking Homework
+
+1. Crypto Wojak - Who is the admin?
+2. Sminem       - Set the password
+3. Crypto Wojak - Make your tries count 2 or more
+4. Crypto Wojak - Make your tries count 2 and get the answer
+5. HODLer       - Deposit ether twice with the same address
+6. Crypto Wojak - Execute selfdestruct()
++1 Sminem       - Create a signature to prove you are Satoshi (see js folder)

docs/topology.drawio

@@ -0,0 +1 @@
+<mxfile host="app.diagrams.net" modified="2022-10-06T20:00:39.755Z" agent="5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.5112.102 Safari/537.36" etag="bC8fl9ZiBndQcjIvywAN" version="20.4.0" type="device"><diagram id="fPFYDeu9YJaB2W5Fxku6" name="Page-1">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</diagram></mxfile>

js/i_am_satoshi.js

@@ -0,0 +1,72 @@
+'use strict';
+
+// original: https://gist.github.com/indutny/8d0f5376ee643962a9f0
+
+// npm install --save bn.js
+// npm install elliptic
+// npm install bcoin
+// npm install secp256k1
+
+const BN = require('bn.js');
+const elliptic = require('elliptic');
+const bcoin = require('bcoin');
+
+const ecdsa = new elliptic.ec('secp256k1');
+
+let message = new BN(
+    '7a05c6145f10101e9d6325494245adf1297d80f8f38d4d576d57cdba220bcb19', 'hex');
+
+var key = new Buffer('0411db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5cb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3', 'hex');
+var sig = '304402204e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd410220181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d09';
+// const signature = new bcoin.ecdsa.signature(new Buffer(sig, 'hex'));
+// console.log(signature);
+
+var signature = {
+  r: new BN('4e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd41', 'hex'),
+  s: new BN('181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d09', 'hex')
+};
+
+const point = ecdsa.curve.pointFromX(signature.r);
+point.precompute(256);
+
+function trick(message, signature, i) {
+  const n = new BN(
+      'fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141', 16);
+  const p = new BN(
+      'fffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f', 16);
+
+  const nRed = BN.red(n);
+  const pRed = BN.red(p);
+
+  // NOTE: Could be using GLV values for speed
+  let lambda = new BN(i);
+
+  const point2 = point.mul(lambda);
+  let beta = point2.x.redMul(point.x.redInvm()).fromRed();
+
+  lambda = lambda.toRed(nRed);
+  beta = beta.toRed(pRed);
+  // NOTE end
+
+  const originalR = signature.r;
+  const r = originalR.toRed(pRed).redMul(beta).fromRed();
+
+  const nBeta = r.toRed(nRed).redMul(originalR.toRed(nRed).redInvm());
+  const common = lambda.redInvm().redMul(nBeta);
+
+  const s = signature.s.toRed(nRed).redMul(common).fromRed();
+
+  return {
+    signature: { r: r, s: s },
+    message: message.toRed(nRed).redMul(nBeta).fromRed()
+  };
+}
+
+for (let i = 2; i < 100; i++) {
+  const item = trick(message, signature, i);
+  console.log(JSON.stringify([
+    new Buffer(item.message.toArray()).toString('hex'),
+    new Buffer(new bcoin.ecdsa.signature(item.signature).toDER()).toString('hex')
+  ]) + ',');
+  // ecdsa.verify(item.message, item.signature, key)
+}

python/bridge.py

@@ -1,7 +1,6 @@
 #!/usr/bin/python3
-
 # Author: six
-# Made for: CCTF during BsidesBUD 2022
+# Made for: CCTF during BsidesBUD 2022 -> Updated for Hacktivity 2022 web3 hacking Workshop
 
 # require(owner() == ecrecover(keccak256(abi.encodePacked(this, tokenId)), v, r, s), "Should be signed correctly");
 # https://privatekeys.pw/keys/ethereum/1
@@ -10,20 +9,14 @@ from web3.auto import w3
 from eth_account.messages import encode_defunct
 from flask import Flask, request
 
-from base64 import b64encode
-
 app = Flask(__name__)
 
-b64 = '''<html><body><pre>Lets play a game... what is the private key if:
+html = '''<html><body><pre>Use /get_a_receipt
-
-SignedMessage(messageHash=HexBytes('0xd65fc3b188dd92cfcb2a193a50840c1b782030fb06c5eee3125dadc48b9042ee'), r=93061353422229139783272046072373682100846510432479107335894930000050943813187, s=18897300799783892124841480819482900155126442998358954848148962214377508383077, v=28, signature=HexBytes('0xcdbedc050cdf4e1a236535365e1563312905fc47aa8238a8ab06decfbb31e64329c77e43945949494800d0c432d037867ea10aad935abf98c63ae2befaf929651c'))
-
-If you send the correct private key as argument to /verify?p=<ARG> in HEX format (without 0x), then you will get the CCTF flag which lets you in to the next yacht event + swag at BsidesBUD.
 </pre></body></html>'''
 
 @app.route('/')
 def hello():
-    return b64
+    return html
 
 @app.route('/verify', methods=['GET'])
 def search():

python/eth_keygen.py

@@ -1,5 +1,5 @@
 #!/usr/bin/python3
-# Eth ECDSA key generator, signer and arg recovery for web3 hacking
+# Eth ECDSA key generator, signer and arg recovery for web3 hacking // Modified for Hacktivity workshop
 # Author: six
 # References: https://web3py.readthedocs.io/en/stable/web3.eth.account.html?highlight=sign#sign-a-message
 # Ethereum Private Keys Directory -> https://privatekeys.pw/keys/ethereum/1
@@ -84,7 +84,7 @@ parser.add_argument("-s", "--sol", help="Print solidity code for ecrecover", act
 args = parser.parse_args()
 
 if args.dgen:
-    forv = generate("Anything","0000000000000000000000000000000000000000000000000000000000000001") # hex|0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf
+    forv = generate("Anything","0000000000000000000000000000000000000000000000000000000000000006") # hex|0xE57bFE9F44b819898F47BF37E5AF72a0783e1141
     gen_vrs(forv)
     sys.exit()
 if args.rgen:
@@ -107,6 +107,6 @@ if args.sol:
     print_sol_recovery()
     sys.exit()
 
-forv = generate("Anything","0000000000000000000000000000000000000000000000000000000000000001") # hex|0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf
+forv = generate("Anything","0000000000000000000000000000000000000000000000000000000000000006") # hex|0xE57bFE9F44b819898F47BF37E5AF72a0783e1141
 gen_vrs(forv)
 print("\nNo arguments were provided. You can use --help.")

python/forgery.py

@@ -1,5 +1,8 @@
 #!/usr/bin/python3
 # Author: SI
+# Reference 1: https://cryptoctf.org/2022/09/11/writeup-of-flag-submission-forgery-by-si/
+# Reference 2: https://polygonscan.com/address/0x36a1424da63a50627863d8f65c0669da7347814a
+# Reference 3: https://gist.github.com/chjj/4fe8f5b2b489e89e6ed4
 
 from eth_account.account import to_standard_signature_bytes
 from eth_keys import keys
@@ -33,8 +36,10 @@ def forge(public_key, a = 0, b = 1):
 
 	return '0x' + to_bytes(z).rjust(32, b'\0').hex(), '0x' + eth_signature_bytes.hex()
 
-hsh = '0xe50051a0af89748fe098cef3b163b6dc586a664e726791bb2a582ad364f42683'
+#hsh = '0xe50051a0af89748fe098cef3b163b6dc586a664e726791bb2a582ad364f42683'
-sig = '0x2bdbc1826efc039719a28a9f4dbab9f4a2692d83de478300261a0e49019b63ee67c202ecc4ebdf82693da47824ac4fcf21f793400d85696034c4de9537c6ce491b'
+#sig = '0x2bdbc1826efc039719a28a9f4dbab9f4a2692d83de478300261a0e49019b63ee67c202ecc4ebdf82693da47824ac4fcf21f793400d85696034c4de9537c6ce491b'
+hsh = '0xbb272d3dc886fccf69f92cd7cb622501c02627c045fb38053f78af2dca68e188'
+sig = '0x30410a2d097af2b27ba3d789ce151c6aed0590f71b4c7b67d4ae91f56659f2297c3a2f8155d9fb9d30682e599b31012b51cb0928578e97f2f3f0c306597d2eec1c'
 
 pub = recover_public_key(hsh, sig)
 addr = pub.to_checksum_address()

solidity/multichain_safu.sol

@@ -1,9 +1,8 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // Challenges inspired by CCTF
 pragma solidity ^0.8.17;
-import "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
 
-contract SafuDotERC20 is AccessControlUpgradeable {
+contract SafuDotERC20 {
     
     uint256 public max_supply;
     mapping (address => uint256) internal amountToAddress;
@@ -18,7 +17,7 @@ contract SafuDotERC20 is AccessControlUpgradeable {
     mapping(address => uint256) public calls;
     mapping(address => uint256) public tries;
     
-    //bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
+    address public bridge;
     mapping(address => bool) public minter;
     
     // Homework 1
@@ -29,8 +28,10 @@ contract SafuDotERC20 is AccessControlUpgradeable {
 
         max_supply = 1000000;
         amountToAddress[msg.sender] = max_supply - 100000;
-        amountOfBridge = max_supply - amountToAddress[msg.sender];
+        bridge = 0xE57bFE9F44b819898F47BF37E5AF72a0783e1141;
+        amountToAddress[bridge] = max_supply - amountToAddress[msg.sender];
         mint_amount = 10000;
+        
         minter[msg.sender] = true;
     }
     
@@ -38,33 +39,38 @@ contract SafuDotERC20 is AccessControlUpgradeable {
         amountToAddress[msg.sender] = amountToAddress[msg.sender] + mint_amount;
     }
 
-    function mintWithReceipt(
+    function mintWithReceipt(bytes32 _message, bytes memory _signature) public {
-        address recipient,
+        require(recoverSigner(_message, _signature) == bridge, "Not signed with the correct key.");
-        uint256 amount,
+        //require(minter[msg.sender] == true, "Not minter");
-        uint256 uuid,
-        uint8 v,
-        bytes32 r,
-        bytes32 s
-    ) public {
-
-        bytes32 payloadHash = keccak256(abi.encode(recipient, amount, uuid));
-        bytes32 hash = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", payloadHash));
         //require(!_receipts[hash], "Receipt already used"); // Dumb without it.
-        _checkSignature(hash, v, r, s);
+        amountToAddress[bridge] = amountToAddress[bridge] - mint_amount;
+        require(amountToAddress[bridge] >= 0);
         mint();
         //_receipts[hash] = true;
     }
 
-    function _checkSignature(
+    function recoverSigner(bytes32 _ethSignedMessageHash, bytes memory _signature) public pure returns (address) {
-        bytes32 hash,
+        (bytes32 r, bytes32 s, uint8 v) = splitSignature(_signature);
-        uint8 v,
+        return ecrecover(_ethSignedMessageHash, v, r, s);
-        bytes32 r,
-        bytes32 s
-    ) internal view {
-        address signer = ecrecover(hash, v, r, s);
-        require(minter[signer] == true, "Not minter");
     }
 
+    function splitSignature(bytes memory sig) public pure returns (bytes32 r, bytes32 s, uint8 v){
+        require(sig.length == 65, "Invalid signature length");
+        assembly {
+            r := mload(add(sig, 32))
+            s := mload(add(sig, 64))
+            v := byte(0, mload(add(sig, 96)))
+        }
+    }
+
+    function myBalance() external view returns (uint256) {
+        return amountToAddress[msg.sender];
+    }
+
+
+    function othersBalance(address _other) external view returns (uint256) {
+        return amountToAddress[_other];
+    }
 
     function transfer(uint256 _value, address _toAddress) external {
         require(amountToAddress[msg.sender] - _value >= 0, 'Oooops');
@@ -77,7 +83,6 @@ contract SafuDotERC20 is AccessControlUpgradeable {
         return sent;
     }
 
-
     // Easypeasy
     function adminChange(address _newAdmin) external returns (bool) {
         admin = _newAdmin;
@@ -90,7 +95,7 @@ contract SafuDotERC20 is AccessControlUpgradeable {
         correct_password = _password;
     }
 
-    // Homework 5 - Final
+    // Homework 6 - Final
     function su1c1d3(address payable _addr, string memory _password) external {
         require(msg.sender == admin, 'You are not the central admin!');
         require(keccak256(abi.encodePacked(correct_password)) == keccak256(abi.encodePacked(_password)), 'Very sekur.');
@@ -113,7 +118,12 @@ contract SafuDotERC20 is AccessControlUpgradeable {
         return answer;
     }
 
-    function deposit() public payable {}
+    // Homework 5
-    fallback() external payable {}
+    mapping(address => bool) address_contributed;
-    receive() external payable {}
+    function deposit() public payable {
+            require(address_contributed[msg.sender] != true, "Not working.");
+            address_contributed[msg.sender] = true;
+    }
+    fallback() external {}
+    //receive() external {}
 }