esCTF Writeup SOUL

import py7zr
import tarfile
import rarfile
import zipfile
import base64
from io import BytesIO

def unzip(bio):
	header = str(bio.read(2).hex())
	bio.seek(0)
	
	# 7z
	if header == "377a":
		return py7zr.SevenZipFile(bio, "r").readall()
	
	# tar
	elif header == "1f8b" or header == b"1f00":	
		tar = tarfile.open(fileobj=bio, mode="r:*")
		files = [(info.name, tar.extractfile(info.name)) for info in tar]
		return { name: BytesIO(bio.read()) for name, bio in files if bio }
	
	# rar
	elif header == "5261":	
		rar = rarfile.RarFile(bio)
		files = [(info.filename, rar.read(info)) for info in rar if not info.is_dir()]
		return { name: BytesIO(bio) for name, bio in files }
	
	# zip
	elif header == "504b":
		zip = zipfile.ZipFile(bio)
		files = [(info.filename, zip.read(info)) for info in zip.infolist() if not info.is_dir()]
		return { name: BytesIO(bio) for name, bio in files }
	
	else:
		raise ValueError(f"unknown header {header}")

f = BytesIO(open("file.7z", "rb").read())
path = []
while True:
	files = unzip(f)
	if len(files.items()) != 1:
		print(files)
		break
	name, bio = list(files.items())[0]
	
	if "/" in name:
		folder, file = name.split("/")
	if file != "OpenMe.zip":
		f = bio
		if len(path) == 0:
			path.append(folder)
		path.append(file)
	else:
		full_path = "".join(path);
		print(full_path)
		decoded = base64.b64decode(full_path).decode("utf8")
		print()
		print(decoded)
		pwd = "".join([c for c in decoded if c.isnumeric()])
		
		zip = zipfile.ZipFile(bio)
		print()
		print(zip.read("flag.txt", bytes(pwd, "utf8")).decode("utf8"))
		break

> py pandora.py

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

Most of us tend to try and avoid mistakes and view them as ne9ative rather than important.
But m1stakes can teach us and h3lp us improve. Understanding the imp0rtance of mistakes and
how to use them to 0ur best advantage is what separa7es out the gr8 leaders from the rest
of the cr0wd. There is a skill to handling mistakes and understanding how to turn them int0
opportuni7ies.We mu5t learn t0 embrace our mistake5 and see them for the less0ns they offer
and the opportun1ties they provide. This is the approach that will catapult our leadership
to success. An exper1mental approach to life and learnin9 must include using mistakes to our
advanta9e. By staying f0cused on the 6ig picture of our life and were w3 are headed, we can
learn to take mistakes in stride 4s part of our pers0nal leadership developmen7.

esTCF{Freed0m_1s_n0t_w0r7h_h4v1n9_1f_1t_d03s_n0t_1nclud3_th3_fr33d0m_t0_m4k3_m15t4k35}

let input = "6dab1eeb8f9e9dca1d8a783e8acfad85efb06b2fada3e75e72875e";

const CHARSET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

let output = [];
for(let i = 0; i < input.length; i += 3){
	let chunk = parseInt(input.substring(i, i + 3), 16)
	output.push(CHARSET[(chunk >> 6) & 0x3f]);
	output.push(CHARSET[(chunk >> 0) & 0x3f]);
}

console.log(`flag: esCTF{${output.join("")}}`);

> node free.js

flag: esCTF{base64+encoding+is+the+way+to+decode}

# source: https://github.com/newaetech/chipwhisperer-jupyter/blob/master/courses/sca101/SOLN_Lab%204_2%20-%20CPA%20on%20Firmware%20Implementation%20of%20AES.ipynb

import numpy

sbox = [
	0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 
	0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 
	0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 
	0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 
	0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 
	0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 
	0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 
	0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 
	0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 
	0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 
	0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 
	0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 
	0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 
	0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 
	0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 
	0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
]

def aes_internal(inputdata, key):
	return sbox[inputdata ^ key]

HW = [bin(n).count("1") for n in range(0, 256)]

def mean(X):
	return numpy.sum(X, axis=0)/len(X)

def std_dev(X, X_bar):
	return numpy.sqrt(numpy.sum((X-X_bar)**2, axis=0))

def cov(X, X_bar, Y, Y_bar):
	return numpy.sum((X-X_bar)*(Y-Y_bar), axis=0)

textin_array = numpy.load("textin_array.npy")
trace_array = numpy.load("trace_array.npy")

t_bar = numpy.sum(trace_array, axis=0)/len(trace_array)
o_t = numpy.sqrt(numpy.sum((trace_array - t_bar)**2, axis=0))

key = [0] * 16
for bnum in range(0, 16):
	maxcpa = [0] * 256
	for kguess in range(0, 256):
		hws = numpy.array([[HW[aes_internal(textin[bnum],kguess)] for textin in textin_array]]).transpose()
		hws_bar = mean(hws)
		o_hws = std_dev(hws, hws_bar)
		correlation = cov(trace_array, t_bar, hws, hws_bar)
		cpaoutput = correlation/(o_t*o_hws)
		maxcpa[kguess] = max(abs(cpaoutput))
	key[bnum] = numpy.argmax(maxcpa)
	print(f"found byte {bnum}")

print()
print(f"key: {''.join(f'{b:02x}' for b in key)}")

> python3 power.py

found bit 0
found bit 1
found bit 2
found bit 3
found bit 4
found bit 5
found bit 6
found bit 7
found bit 8
found bit 9
found bit 10
found bit 11
found bit 12
found bit 13
found bit 14
found bit 15

key: beccca0b9abc7c8e37d6b185d8b4bace

#!/bin/sh

pin="-";
new_pin="";
while [ "${pin}" != "${new_pin}" ]; do
	pin="${new_pin}";
	max_calls=0;
	for i in $(seq -1 9); do
		sleep_count=$(echo "${new_pin}${i}" | ltrace ./kingpin |& grep -c usleep);
		if [ "${max_calls}" -lt "${sleep_count}" ]; then
			if [ "${i}" -gt -1 ]; then
				new_pin="${pin}${i}";
				echo "${new_pin}";
				break;
			fi
			max_calls="${sleep_count}";
		fi
	done
done

echo;
echo "pin is ${pin}";

echo "${pin}" | ./kingpin

> ./kingpin.sh

8
80
804
8047
80471
804715
8047156
80471563
804715635
8047156357

pin is 8047156357
 ____  __.__              __________.__
|    |/ _|__| ____    ____\______   \__| ____
|      < |  |/    \  / ___\|     ___/  |/    \
|    |  \|  |   |  \/ /_/  >    |   |  |   |  \
|____|__ \__|___|  /\___  /|____|   |__|___|  /
        \/       \//_____/                  \/


KingPin, Enter your pin >
Welcome KingPin!!!

Here is your flag: esCTF{8047156357}.