LoRexxar's Blog

hctf_game_week1_writeup

2016/02/18

假期难得有时间空闲下来,就和协会的小伙伴组织了一次比较简单的ctf比赛针对学校的学弟学妹们,这里就贴上每一次的writeup,以供整理复习用。

WEB

WEB从0开始之PHP代码审计0 POINT: 100 DONE

题目ID: 55
题目描述: http://ctf.lazysheep.cc:8081/web1.php
Hint: 前置技能:PHP

题目的原题是出在hctf2015的fuck===,出题思路来自http://www.secbox.cn/hacker/1889.html.
payload: ?a[]=adsa&b[]=dsadsa
这里之所以===能过,是因为在php中,md5不能加密数组,会返回null,null==null返回flag

MISC

MISC 驾驶技术科目一 POINT: 100 DONE

题目ID: 36
题目描述: 如果玩转 MISC 快来开始你的科目一吧! 链接: http://pan.baidu.com/s/1c1c7fiC 密码: cyyd
Hint: 噫 都上些啥站呀

科目一比较简单,和之前的流量分析类似,大概就是一个http明文请求,仔细找找很快就能找到。flag中顺便找到科目二的入口。

MISC 驾驶技术科目二 POINT: 100 DONE

题目ID: 37
题目描述: 考完科目一的小伙伴快过来科目二啦,早上上路,争当中国好司机。
Hint: 无

科目二找到后发现是一张图片,这里使用到一个linux下的工具,binwalk,可以发现图片是由多个文件合并的,使用foremost就可以把所有的东西拆开来,得到flag的二维码,扫码getflag。

MISC从0开始之编码1 POINT: 75 DONE

题目ID: 49
题目描述: 老司机的题目做不出来?丢一题简单的给你们做。。
http://ctf.lazysheep.cc:8081/misc1.html
Hint: base全家桶,老司机们别抢新生的前三血啊~

这里就是base全家桶了,目前好像没见过用python以外的方式做的,不过如果自己写代码实现应该也是可以的。

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import base64
bb64=base64.b64encode('xxxxx')
bb32=base64.b32encode(bb64)
b=base64.b16endcode(bb32)
print b

大概就是这样…

MISC从0开始之流量分析1 POINT: 75 DONE

题目ID: 53
题目描述: http://ctf.lazysheep.cc:8081/misc1.pcap
Hint: 暂无HINT

比较接近一般题目的流量分析了,可以看到在最后一个http请求中请求了一个flag的zip文件。那么就需要wireshark加一个16进制编辑器把这个文件扣出来了,一般网上还是能搜到教程的,懒得赘述了。

CTF coding step1 POINT: 50 DONE

题目ID: 47
题目描述: 打CTF就是拿工具? 不不不,也要写很多代码的。这个系列就是让你熟悉CTF风格的编程题目,具体的要求见题目吧のの 就是让你们多看点英文:
nc 115.29.77.78 9979
Hint: repr

nc连上发现是计算数学式子,那么开始写代码吧。

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import socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(('115.29.77.78',9979))
import time
sock11=sock.recv(1024)
print sock11
sock11=sock.recv(1024)
print sock11
pos2=sock11.find('=',950)
sendr = eval(sock11[945:pos2])
print sendr
sock.send(repr(sendr)+'\n')
while 1:
sock11=sock.recv(1024)
print sock11
pos=sock11.find('=')
i=sock11.find(']')
if(i!=-1):
sendr=eval(sock11[i+2:pos].replace('\xc3\x97','*'))
print sendr
sock.send(repr(sendr)+'\n')
else:
sendr=eval(sock11[:pos])
print sendr
sock.send(repr(sendr)+'\n')
sock.close()

因为是第一次写socket,所以还是踩了不少坑,首先这个文件不能叫做socket.py否则不能通过编译,其次就是每一个send必须在后面加上’\n’否则不会有下一步,自己试试吧。。。

crypto

密码学从0开始之1 POINT: 20 DONE

题目ID: 50
题目描述: http://ctf.lazysheep.cc:8081/cry1.html
flag不是标准格式,提交你解出的明文就行,flag全是大写
Hint: 这个简单,应该不需要hint

打开看到一堆点啊横啊就知道是摩斯密码,随便一搜都能搜到各种解码

密码学从0开始之1.1 POINT: 150 DONE

题目ID: 54
题目描述: http://ctf.lazysheep.cc:8081/cry2.html
你知道01的奥秘么?
Hint: 这可不是啥古典密码了

打开看到0101,第一反应是看看有多少位,能除开8的话,八成是要转ascii码,那就写个代码吧

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import binascii
f = file('./test','w+')
str11 = '1000100101010000010011100100011100001101000010100001101000001010000000000000000000000000000011010100100101001000010001000101001000000000000000000000000010110010000000000000000000000000001100100000100000000110000000000000000000000000111110000011101010000001101100000000000000000000000001010011110101001001010001000100000101010100011110001001110011101101100111001100111101001011100110110100100100011000110001111011111111011001111011100001111110100000110100000100101100100100100010110001111000001100100000101101010001001011000101110001010011011101000001010000111101011101000101101011011000001010100011011001000100010110011011110000000110111011110110001000001010110000101001101000011111100010000010100101101010001010000011010111010010010111000111101011010010000111100000100001101110010110010000000110111010100101010010110110110110000100011101010000111110100101001111010000100001010101010100010101100000101111010010101100000110011010010000110110010011000101010111000000101011110001000111111001000011101100110011001111101100100011001001100110111111011110100110000011011111110011110011101111101100110110000110011001111000001111000001001101101000110111111011110011110011101111011001001110011000111011110011111111001110011101011110010100101100000011100001011001001101001100000100010000010011010001111000100111110011110101101001010011101101000000000100000011001000100000001000010001001101001010010000000100001000100110100101001000000010000100010011000010100000000001000010011001100101010000000000100001001000110010101000010000010000100100011001000100001000001001010010001100100010000100000100101001000010010000000010010010010100100000001000010001001101001010010000000100001000100110100101001000000010000100010011000010100000000001000010011001100101010000000000100001001000110010101000010000010000100100011001000100001000001001010010001100100010000100000100100100100000010001111100101111011001100100000001001110110110010011001110010001100110100001011011000110100101011011110110111100000001001000100010000011110110000011011111010100011000011110100111010011011111010100110101100100100111011111101101000111101101101110011011001110000011110011011011101101000001000101001011111110010111000101111100010001101000110111111000111101100110101100001101000111110101000110011011101101101111001101111000011101111011110100000100100011000011111001000110101000010110010011000011001101011000010111101011111110100011010111010101111101001001010010001001101010001001101101111101110001110010011111100011100110010111110100010100110100111000011100010001111100111100110010011111100111101110111011100000000001100011001011110001111011001110111000101110101000001111001101110100010101000011001101110001011100111001111111010100111111101001000110111000110100100111001010010111000010100010110011001010111111101010000010111111101111110001101000010000011110101110100111111110010111011100101111011010000001101000100001111100110000000110011110101101011111101110110001111110010110001100011100101000000000111101110111101111100000110110010101110111010111101110001110111001110111111110111101110000010001000010011011100011001001001010110000011010111011010110101111110000110101100111111111000101011100010011011110011001110101000001111000001111111000110010101011111111010111100111100001111111101100101110001010010100110000111100101110111000100100000000100010100010111110010100010111001110111001101000010000100010110010111100011110000000001010100101110001111001110110001010110110000110010100111101101111111010000100001110101111001100010001010101010111000101111001111110100000001110000011111110000110011001001110001000110111011011000111101101010100101011011001101001000110110010000011010111001001111001111011000001010101011101011111000100111111011111000011110000000100101011100111010101111000001111010001100111001101100001011011100110000000111100011110001101011101110011001001100001111010000010000100111000100000001111011101100110000111101011011100110100001111110011100010110001001101110111100110111000111100011111010010000011011000100001010010000100001111110000110100101100010101101100100101100101000010111101000100111110111010011010101111010110011001010110011011001101110100100011111110000100100111011110011011101101000000001101001000111000100100101110110010011110011001000110000010100010010101010010110101111011110010000000100000100100110110011100011101100001000111011111001001101001011111010111110100000001111010101011010111101010110010011010101011010101110111110110100011011110101011101101111011010111110110110100110110100110010110100101110001010110100111011001101011101111111100000001111011110001100010000010110111100010101010011111111011000011100010111111101110111010001110011011101110000011110000000111011101011011101011000101000000001011101011011110000000011010100010001111111110001101111001000000111100010110100011110111000110101011010100100110110110101110111111100100010010011111100100101101110111000111000100111100000101100011110011101100011100010111010101011001010100110011100001000011010110111011001110101111011011110010011000010101000101111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for k in xrange (0,11184,8):
stt=str11[k:k+8]
f.write(chr(int(stt,2)))
f.close()

突然发现好长啊。。。出来时一张图片,get!

pentest

lightless&aklis的渗透教室-2 POINT: 75 DONE

题目ID: 45
题目描述: http://120.27.53.238/pentest/02/http-header.php
Hint: Mozilla/5.0 (iPhone; CPU iPhone OS 9_0 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Version/9.0 Mobile/13A344 Safari/601.1
xff: 127.0.0.1

坑已经被踩完了还所做不出那就没办法了,记得要改ios99啊,hint中的是ios9的…

记得看文档啊!!!

CATALOG
  1. 1. WEB
    1. 1.1. WEB从0开始之PHP代码审计0 POINT: 100 DONE
  2. 2. MISC
    1. 2.1. MISC 驾驶技术科目一 POINT: 100 DONE
    2. 2.2. MISC 驾驶技术科目二 POINT: 100 DONE
    3. 2.3. MISC从0开始之编码1 POINT: 75 DONE
    4. 2.4. MISC从0开始之流量分析1 POINT: 75 DONE
    5. 2.5. CTF coding step1 POINT: 50 DONE
  3. 3. crypto
    1. 3.1. 密码学从0开始之1 POINT: 20 DONE
    2. 3.2. 密码学从0开始之1.1 POINT: 150 DONE
  4. 4. pentest
    1. 4.1. lightless&aklis的渗透教室-2 POINT: 75 DONE