2020西湖论剑CTF部分MISC——Write Up
前言
谢谢盖师傅，本文章部分题目参考盖师傅的WP再详细的解释每一步的解题步骤，盖师傅yyds
还有借用了核平师傅的脚本进行解题，核平师傅yyds
Yusapapa
题目地址：http://yusa-papa.7bf48c.challenge.gcsis.cn/
查看题目所给网站的源码，其中有一段注释
1. Maybe these texts are really helpful for you
2. Biometric list is OK!
3. endow gremlin indulge bison flatfoot fallout goldfish bison hockey
fracture fracture bison goggles jawbone bison flatfoot gremlin
glucose glucose fracture flatfoot indoors gazelle gremlin goldfish
bison guidance indulge keyboard keyboard glucose fracture hockey
bison gazelle goldfish bison cement frighten gazelle goldfish
indoors buzzard highchair fallout highchair bison fallout goldfish
flytrap bison fallout goldfish gremlin indoors frighten fracture
highchair bison cement fracture goldfish flatfoot gremlin flytrap
fracture buzzard guidance goldfish freedom buzzard allow crowfoot
jawbone bison indoors frighten fracture bison involve fallout
jawbone Burbank indoors frighten fracture bison guidance gazelle
flatfoot indoors indulge highchair fracture bison hockey frighten
gremlin indulge flytrap bison flagpole fracture bison indulge hockey
fracture flytrap bison allow blockade endow indulge hockey fallout
blockade bison gazelle hockey bison inverse fracture highchair
jawbone bison gazelle goggles guidance gremlin highchair indoors
fallout goldfish indoors bison gazelle goldfish bison indoors
frighten gazelle hockey bison flatfoot frighten fallout glucose
glucose fracture goldfish freedom fracture blackjack blackjack
直接搜下面那一大堆内容，就可以找到是PGP词汇表，对着表替换一下，得到
59 6F 75 20 63 61 6E 20 73 65 65 20 6D 79 20 63 6F 6C 6C 65 63 74 69 6F 6E 20 70 75 7A 7A 6C 65 73 20 69 6E 20 2F 68 69 6E 74 2E 72 61 72 20 61 6E 64 20 61 6E 6F 74 68 65 72 20 2F 65 6E 63 6F 64 65 2E 70 6E 67 2E 0A 42 79 20 74 68 65 20 77 61 79 2C 74 68 65 20 70 69 63 74 75 72 65 20 73 68 6F 75 64 20 62 65 20 75 73 65 64 20 0A 22 59 75 73 61 22 20 69 73 20 76 65 72 79 20 69 6D 70 6F 72 74 61 6E 74 20 69 6E 20 74 68 69 73 20 63 68 61 6C 6C 65 6E 67 65 21 21
用010导入十六进制得到
You can see my collection puzzles in /hint.rar and another /encode.png.
By the way,the picture shoud be used
"Yusa" is very important in this challenge!!
根据给的目录，下载得到hint.rar和encode.png，在网站首页源码中还可以发现一个encode.webp，也保存下来
防止时间过长，题目地址可能出现无法访问，我用百度网盘分享一下这三个文件，希望先按照上面的一步一步操作，再拿分享的文件
链接:https://pan.baidu.com/s/1HCFXC3j1DNAdPz7RHKX0Vg 密码:fvev
解webp文件隐写用到stegpy，无密钥直接解，可以得到压缩包密码
工具传送门：https://github.com/Baldanos/Stegpy.git
压缩包密码：Yus@_yydsstegpy!!
根据题目所给hint，找到一个加密工具：InvisibleSecret
用Unhide Files选项，选择hint.jpg，选择Blowfish加密，密钥为Yusa
解得一个加密脚本，在网上找到盖师傅写的根据加密脚本写解密脚本，得到flag，盖师傅yyds
from PIL import Image,ImageDraw
hide=Image.open('encode.png').convert('RGB')
R=[]
G=[]
B=[]
a,b = hide.size
for x in range(a):
for y in range(b):
R.append(hide.getpixel((x,y))[0] & 1)
G.append(hide.getpixel((x,y))[1] & 1)
B.append(hide.getpixel((x,y))[2] & 1)
flag = [r^g^b for r,g,b in zip(R,G,B)]
for i in range(len(flag)):
if flag[i] == 1:
flag[i] = 255
en_p = Image.new('L',(a,b),255)
for x in range(a):
for y in range(b):
en_p.putpixel((x,y),(flag[y+x*b]))
en_p.save('flag.png')
用python3环境跑脚本得出flag
指鹿为马
先输入1拿到题目的py脚本
import numpy as np
from PIL import Image
import math
import operator
import os
import time
import base64
import random
def load_horse():
data = []
p = Image.open('./horse.png').convert('L')
p = np.array(p).reshape(-1)
p = np.append(p,0)
data.append(p)
return np.array(data)
def load_deer():
data = []
p = Image.open('./deer.png').convert('L')
p = np.array(p).reshape(-1)
p = np.append(p,1)
data.append(p)
return np.array(data)
def load_test(pic):
data = []
p = Image.open(pic).convert('L')
p = np.array(p).reshape(-1)
p = np.append(p,1)
data.append(p)
return np.array(data)
def euclideanDistance(instance1, instance2, length):
distance = 0
for x in range(length):
distance += pow((instance1[x] - instance2[x]), 2)
return math.sqrt(distance)
def getNeighbors(trainingSet, testInstance, k):
distances = []
length = len(testInstance) - 1
for x in range(len(trainingSet)):
dist = euclideanDistance(testInstance, trainingSet[x], length)
distances.append((trainingSet[x], dist))
distances.sort(key=operator.itemgetter(1))
neighbors = []
for x in range(k):
neighbors.append(distances[x][0])
return neighbors
def getResponse(neighbors):
classVotes = {
}
for x in range(len(neighbors)):
response = neighbors[x][-1]
if response in classVotes:
classVotes[response] += 1
else:
classVotes[response] = 1
sortedVotes = sorted(classVotes.items(), key=operator.itemgetter(1), reverse=True)
return sortedVotes[0][0]
def getAccuracy(testSet, predictions):
correct = 0
for x in range(len(testSet)):
if testSet[x][-1] == predictions[x]:
correct += 1
return (correct / float(len(testSet))) * 100.0
def check(pic):
source_p = Image.open('deer.png')
try:
c_p = Image.open(pic)
except:
print("Please upload right picture.")
exit()
diff_pixel = 0
a, b = source_p.size
if c_p.size[0] != a and c_p.size[1] != b:
print("Please upload right picture size("+str(a)+','+str(b)+')')
exit()
for y in range(b):
for x in range(a):
diff_pixel += abs(source_p.getpixel((x, y)) - c_p.getpixel((x, y)))
return diff_pixel
def main():
while 1:
print('-' * 134)
print(''' ____ __ _ _ _ _ _ _ _
| __ \ / _| | | | | | | | | | | | | | |
| |__) |___| |_ ___ _ __ | |_ ___ | |_| |__ ___ __| | ___ ___ _ __ __ _ ___ | |_| |__ ___ | |__ ___ _ __ ___ ___
| _ // _ \ _/ _ \ '__| | __/ _ \ | __| '_ \ / _ \ / _` |/ _ \/ _ \ '__| / _` / __| | __| '_ \ / _ \ | '_ \ / _ \| '__/ __|/ _ \\
| | \ \ __/ || __/ | | || (_) | | |_| | | | __/ | (_| | __/ __/ | | (_| \__ \ | |_| | | | __/ | | | | (_) | | \__ \ __/
|_| \_\___|_| \___|_| \__\___/ \__|_| |_|\___| \__,_|\___|\___|_| \__,_|___/ \__|_| |_|\___| |_| |_|\___/|_| |___/\___|
''')
print('-'*134)
print('\t1.show source code')
print('\t2.give me the source pictures')
print('\t3.upload picture')
print('\t4.exit')
choose = input('>')
if choose == '1':
w = open('run.py','r')
print(w.read())
continue
elif choose == '2':
print('this is horse`s picture:')
h = base64.b64encode(open('horse.png','rb').read())
print(h.decode())
print('-'*134)
print('this is deer`s picture:')
d = base64.b64encode(open('deer.png', 'rb').read())
print(d.decode())
continue
elif choose == '4':
break
elif choose == '3':
print('Please input your deer picture`s base64(Preferably in png format)')
pic = input('>')
try:
pic = base64.b64decode(pic)
except:
exit()
if b" in pic or b'eval' in pic:
print("Hacker!!This is not WEB,It`s Just a misc!!!")
exit()
salt = str(random.getrandbits(15))
pic_name = 'tmp_'+salt+'.png'
tmp_pic = open(pic_name,'wb')
tmp_pic.write(pic)
tmp_pic.close()
if check(pic_name)>=100000:
print('Don`t give me the horse source picture!!!')
os.remove(pic_name)
break
ma = load_horse()
lu = load_deer()
k = 1
trainingSet = np.append(ma, lu).reshape(2, 5185)
testSet = load_test(pic_name)
neighbors = getNeighbors(trainingSet, testSet[0], k)
result = getResponse(neighbors)
if repr(result) == '0':
os.system('clear')
print('Yes,I want this horse like deer,here is your flag encoded by base64')
flag = base64.b64encode(open('flag','rb').read())
print(flag.decode())
os.remove(pic_name)
break
else:
print('I want horse but not deer!!!')
os.remove(pic_name)
break
else:
print('wrong choose!!!')
break
exit()
if __name__=='__main__':
main()
在输入2 拿到两个图片的base64值
（转码网站https://tool.jisuapi.com/base642pic.html）
马的base64
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
鹿的base64
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
输入3，提示输入图片：Please input your deer picture`s base64(Preferably in png format)
经过代码审阅，发现题目的要求是要你输入一张图片（这里称为test）的base64编码，通过他的条件就会得到flag。
我们发现在传入马和鹿和test时，load_horse()，load_deer()，load_test(),图片的尾部会被添加一个值，除了马是0，其他两张都是1，这是重点！！
在看输入图片后的判断流程，第一个条件check()，check()的作用是将test和鹿的像素差的绝对值相加，如果大于10w就不通过。第二个条件getNeighbors(),比较test和马和鹿的像素的欧式距离。如果test和马的欧氏距离最近才能通过。getResponse()的作用就是判断图片的尾部是否为0（感觉这代码也是作者从其他地方扒拉过来的，图片对抗）。
所以我们就理清思路了，我们要输入一张test，test的总像素差和鹿不能超过10w，并且和马的欧式距离最近。真是“指鹿为马”啊。
一开始我是想用PS将两个图片叠加再一起的，可是一直过不了，还尝试了几次不同比例叠加，也不行，听说有大佬用PS过了。我还是交给脚本吧···，我的思路是在鹿的基础上将马的像素点一个一个加上去，直到满足两个条件就停止。这个脚本我借用大佬的脚本核平先生，大佬yyds
from PIL import Image
ma = Image.open('./horse.png').convert('L')
print(ma)
print(ma.size)
print(ma.getpixel((0, 70)))
lu = Image.open('./deer.png').convert('L')
luandma = Image.open('./deer.png').convert('L')
for i in range(72):
for j in range(72):
px = ma.getpixel((i, j))
luandma.putpixel((i,j),px)
diff_pixel = 0
distance1 = 0
distance2 = 0
for y in range(72):
for x in range(72):
distance1 += pow(abs(lu.getpixel((x, y)) - luandma.getpixel((x, y))), 2)
distance2 += pow(abs(ma.getpixel((x, y)) - luandma.getpixel((x, y))), 2)
diff_pixel += abs(lu.getpixel((x, y)) - luandma.getpixel((x, y)))
if diff_pixel <= 100000 and distance1 > distance2:
print("ok")
luandma.save('done.png')
exit()
脚本跑完后得出一张图，果然是两个图合在一起，第一次见
把图片进行转换base64
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
输入3 然后把合成图片的base64输入
然后base64转码成txt后发现里面还有图片的base64，再转，才是最后的flag
Barbar
分离附件二维码后的压缩包，可以得到一个加密的压缩包，提示密钥32位，无法爆破
扫码可以发现在密和码之间还藏有其他信息，这是很明显的零宽度字符隐写
然后用微信扫一下，把输出框里面的所以字符复制到这个网站进行解码https://yuanfux.github.io/zero-width-web/
这个就是压缩包密码
YcfVgMBUraXftwO6Cp92YBGAbyRyWNOO
解压得到一个坏了的qrcode和一个word文档，先看word文档，里面内容没有什么隐写的地方，所以想到把后缀改成zip，依次查看里面的文件，在document.xml这个文件里可以发现一大串base64，复制的时候把所有的
都要删掉
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zqxhfeYmOd60sM0N7imxnLCfSqrOrGF95iY53rSwzQ3uKbGcsJ9Kqs6sYX3mJvG/ANjBFLuX5iZJ
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pbsnvEeJflEPhDk1qs2sUW1mU7p7wnuU6Bf1QJhTo9rMGtVmNqW7J7xHyfJiA4P71BTbW07YTzWs
r/n4PbGBwX1qiu0tJ+ynGtbXfPye2MDgPjXF9pYT9lMN62s+fk9sYHCfmmJ7ywn7qYb1P5DvC8T6
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pOrMkjSnhvWZU6Pa7CTHmxa2kqozS6rOLElzalifOTWqzU6yvOgAuUksN57ef3VuLAs7yNwklhtP
7786N5aFHWRuEsuNp/dfnRvLwg4yN4nlxtP7r873/Pv3P5ySkc0n6rmgAAAAAElFTkSuQmCC
转码发现是个png，转成png是一个aztec码，扫码可得
经扫描得出
扫描工具网站https://demo.dynamsoft.com/dbr_wasm/barcode_reader_javascript.html
进来这个网站扫描前必须选中SETTINGS进行设置添加阿兹台克代码才能识别出来
di`f {
e1c64e14db14c6bb8faabab5bd7be1dc}
再看那个损坏的qrcode，只缺少了三个定位码，用PS补全即可扫出来，但是扫码并不能得到任何有用信息，也没有零宽隐写。
所以需要转换思路，观察这个损坏的二维码的图案，实际上是一种基于颜色和像素的编程语言：piet
这种编程语言有在线的解释器，搜索npiet即可找到：npiet
上传图片，选择最下面的那个选项
在input string处输入通过aztec码得到的那串和flag极为相似的字符串，点击运行，即可得到flag
flag{
f2d76g36fd16cbb6abaaf8db57cbd1ed}