securityoverridehacking challenge 解題思路彙總——Programming

上一部分在steganography遇到了困難，直接跳過。於是就進入最拿手的programming部分了。這部分我是用python完成的，並且通過直接寫入剪切板來提高提交速度。除了captcha的解析，其他基本都沒什麼難度。在這裏我也不過多解釋了，直接上代碼，也沒啥註釋。

6 Programming

6.1 Basic String Manipulation

<span style="font-size:14px;">import sys,gtk

input = sys.argv[1];
result = ['a']* len(input)
result[0] = input[0]
for i in range(1,len(input)):
	result[i] = input[len(input)-i]
result = "".join(result)
print result

clipboard = gtk.clipboard_get()
clipboard.set_text(result)
clipboard.store()</span>

6.2 Basic ASCII Manipulation

<span style="font-size:14px;">import sys,gtk

input = sys.argv[1];
sum = 0;
for c in input:
	sum+=ord(c);
print sum
clipboard = gtk.clipboard_get()
clipboard.set_text(str(sum))
clipboard.store()
</span>

6.3 Word Unscrambling

<span style="font-size:14px;">import sys,gtk

file = open('list.txt','r')
dict = {}
for word in file.read().split(', '):
	sum=0
	for c in word:
		index = ord(c)-96
		sum = sum + index*index
	# print sum,word
	dict[sum] = word;
input = input("Enter the word list: ")
list = []
for word in input.split(', '):
	sum=0
	for c in word:
		index = ord(c)-96
		sum = sum + index*index
	print word,dict[sum]
	list.append(dict[sum])
print ', '.join(list)
clipboard = gtk.clipboard_get()
clipboard.set_text(', '.join(list))
clipboard.store()
</span>

6.4 Basic Geometry

<span style="font-size:14px;">import sys,math,gtk

length = float(sys.argv[1]);
print math.sqrt(length*length*5)
clipboard = gtk.clipboard_get()
clipboard.set_text(str(math.sqrt(length*length*5)))
clipboard.store()
</span>

6.5 String Positioning

<span style="font-size:14px;">import sys,gtk

file = open('data.txt','r')
list = []
row = 1
for line in file:
	col = 0
	for c in line:
		if c == '@':
			list.append('{0}-{1}'.format(row, col))
			print '{0}-{1}'.format(row, col)
		col+=1
	row+=1
print ', '.join(list)
clipboard = gtk.clipboard_get()
clipboard.set_text(', '.join(list))
clipboard.store()
</span>

6.6 Trinomial Factoring

<span style="font-size:14px;">import sys,math,gtk

x = int(sys.argv[1])
y = int(sys.argv[2])
i = 1
while i < x:
	if i*(x-i)==y:
		print '(x+{0})(x+{1})'.format(i,y/i)
		clipboard = gtk.clipboard_get()
		clipboard.set_text('(x+{0})(x+{1})'.format(i,y/i))
		clipboard.store()
		exit()
	i+=1</span>

6.7 Prime Factorization

<span style="font-size:14px;">import sys,gtk

num = int(sys.argv[1])
i = 2
sum = 0
while num > 1:
	if num%i == 0:
		sum += i
		num /= i
	else:
		i+=1
print sum
clipboard = gtk.clipboard_get()
clipboard.set_text(str(sum))
clipboard.store()</span>

6.8 Advanced Geometry

<span style="font-size:14px;">import sys,math,gtk

a = float(sys.argv[1]);
b = float(sys.argv[2]);
c = float(sys.argv[3])/2;
print a*a,b*b,c*c
b=b-math.sqrt(a*a-c*c)
print '%.3f'%math.sqrt(b*b+c*c)
clipboard = gtk.clipboard_get()
clipboard.set_text('%.3f' % math.sqrt(b*b+c*c))
clipboard.store()
</span>

6.9 Calender Algorithm

<span style="font-size:14px;">import sys,datetime,re,gtk

month = {'January':1,'February':2,'March':3,'April':4,'May':5,'June':6,\
'July':7,'August':8,'September':9,'October':10,'November':11,'December':12}

week = ['Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sunday']

result = []

input = sys.argv[1]
for date in input.split(';'):
	g = re.search("([a-zA-Z]*) ([\d]*), ([\d]*)", date)
	if g:
		result.append(week[datetime.date(int(g.group(3)),month[g.group(1)],int(g.group(2))).isocalendar()[2]-1])

print '; '.join(result)
clipboard = gtk.clipboard_get()
clipboard.set_text('; '.join(result))
clipboard.store()
</span>

6.10 Crawler Script

<span style="font-size:14px;">import sys,urllib2,gtk

password = sys.argv[1].split("; ")
result = []
opener = urllib2.build_opener()
opener.addheaders = [("Host","securityoverride.org"),("User-Agent","Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:41.0) Gecko/20100101 Firefox/41.0"),("Cookie","fusion_visited=yes; _ga=GA1.2.271230493.1440901337; fusion_user=20054.d30ac1dc453e1123b35cada839aa4cb1; PHPSESSID=33ced08d8edb04f818cef0eb7b1c4436; fusion_lastvisit=1443238804; _gat=1")]
for i in range(1,101):
	content = opener.open("http://securityoverride.org/challenges/programming/10/moo/%d/"%i).read()
	if content in password:
		result.append("%d:%s"%(i,content))
print "; ".join(result)
clipboard = gtk.clipboard_get()
clipboard.set_text('; '.join(result))
clipboard.store()</span>

6.11 Captcha Cracking

這一題需要說明一下，因爲我是沒有做出來的。我嘗試了多個開源的ocr庫，最主要的就是gocr和tesseract-ocr，結果都不能保證百分百正確。主要是這題給的圖片分辨率極低，因此很難準確識別。在我的代碼中，我嘗試了暴力破解，即自動下載圖片，自動提交，但是跑了一個通宵也沒有成功。基本上來說，錯誤是肯定的。看了下論壇裏面的討論，似乎做出來的人都是自己寫的ocr算法，然後自己給sample解出來。這樣子確實能夠針對這個題目給出比較高的正確率，因爲sample和實際圖片是一致的。不過估計寫這個算法耗時會比較多，興趣不大，也就直接跳過了。

<span style="font-size:14px;">import sys,urllib2,gtk,os,urllib,time
opener = urllib2.build_opener()
opener.addheaders = [("Host","securityoverride.org"),("User-Agent","Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:41.0) Gecko/20100101 Firefox/41.0"),("Cookie","fusion_visited=yes; _ga=GA1.2.271230493.1440901337; fusion_user=20054.d30ac1dc453e1123b35cada839aa4cb1; PHPSESSID=952a6630f6dbc8e747e0b9ce40da9c99; fusion_lastvisit=1443242238; _gat=1"),("Accept","image/png,image/*;q=0.8,*/*;q=0.5")]

while True:
	time.sleep(20)
	opener.open('http://securityoverride.org/challenges/programming/11/index.php').read()
	content = opener.open("http://securityoverride.org/challenges/programming/11/php_captcha.php").read()

	imageFile = open("captcha.jpeg","w")
	imageFile.write(content)
	imageFile.close()

	os.system("convert -sharpen 2 -resize 120% captcha.jpeg captcha.pnm")
	# os.system("export TESSDATA_PREFIX='/usr/share/tesseract-ocr';tesseract captcha.pnm out -l eng -psm 7 hexs")
	# result = os.popen('cat out.txt').read()

	result = os.popen('gocr -i captcha.jpeg -C 0-9a-f').read().replace('\n','').replace('\r','');


	print result

	values = {'string':result,'submitbutton':'12 seconds to Submit',"CSRF_TOKEN":"<?php echo $_SESSION['CSRF_TOKEN'];?>"}
	print values
	post_data = urllib.urlencode(values)
	response = opener.open('http://securityoverride.org/challenges/programming/11/index.php', post_data)
	page_result = ""
	finished = False
	while not finished:
    		data = response.read()
    		page_result+=data
    		if not data:
        		finished = True
	if "You have entered an incorrect string." not in page_result:
		print page_result
		break;
	print "next round"
	pass
</span>

6.12 (5 Variable Equation)^3

<span style="font-size:14px;">a=b=c=d=e=1
max = 10
while a < max:
	b = 1
	while b < max:
		c = 1
		while c < max:
			d = 1
			while d < max:
				e=1
				while e < max:
					sum = a+b+c+d+e
					result = a*10000+b*1000+c*100+d*10+e
					# print resut
					if sum*sum*sum == result:
						print a,b,c,d,e
					e+=1
				d+=1
			c+=1
		b+=1
	a+=1
print "none"</span>

6.12 Barcode Interpretation

<span style="font-size:14px;">def decode(list):
	if list[0] == 3:
		if list[1] == 2:
			return 0
		if list[1] == 1:
			return 9
	if list[0] == 2:
		if list[1] == 2:
			return 1
		if list[1] == 1:
			return 2
	if list[0] == 1:
		if list[1] == 4:
			return 3
		if list[1] == 3:
			return 7
		if list[1] == 2:
			if list[2] == 3:
				return 5
			if list[2] == 1:
				return 8
		if list [1] == 1:
			if list[2] == 3:
				return 4
			if list[2] == 1:
				return 6

import sys,urllib2,gtk,os,urllib,time
from PIL import Image
opener = urllib2.build_opener()
opener.addheaders = [("Host","securityoverride.org"),("User-Agent","Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:41.0) Gecko/20100101 Firefox/41.0"),("Cookie","fusion_visited=yes; _ga=GA1.2.271230493.1440901337; fusion_user=20054.d30ac1dc453e1123b35cada839aa4cb1; PHPSESSID=952a6630f6dbc8e747e0b9ce40da9c99; fusion_lastvisit=1443242238; _gat=1"),("Accept","image/png,image/*;q=0.8,*/*;q=0.5")]


content = opener.open("http://securityoverride.org/challenges/programming/13/img.php").read()

imageFile = open("img.png","w")
imageFile.write(content)
imageFile.close()
os.system("convert img.png img.pnm")

im = Image.open('img.pnm')

pixels = list(im.getdata())
result = [] 
lastColor = 255
count = 0
for i in range(3,46):
	if pixels[i][0] == lastColor:
		count+=1
	else:
		result.append(count)
		count = 1
		lastColor = pixels[i][0]
lastColor = 0 
count = 0
for i in range(50,87):
	if pixels[i][0] == lastColor:
		count+=1
	else:
		result.append(count)
		count = 1
		lastColor = pixels[i][0]
result = [decode(result[4*i:4*i+4]) for i in range(11)]
print result
sum = sum([result[i*2] for i in range(6)]) * 3 + sum(result[i*2+1] for i in range(5))
print "%d:%d"%(sum,sum/10*10+10-sum)
clipboard = gtk.clipboard_get()
clipboard.set_text("%d:%d"%(sum,sum/10*10+10-sum))
clipboard.store()
</span>