MoeCTF2023web

01http

打开题目环境 

可以看到要求完成所有任务，这里用burp抓个包

按照要求修改可以得到flag

moectf{basic_http_knowledge_HJbg427uFuznTqiJdtS1xhZNwpdsOnKU}

02 Web入门指北

直接找到结尾发现乱码，去解码 

编码可以试试url编码和base64到16

这里用不到base64解码但是分享一个特别好用的网址

Base64编码转换工具，Base64加密解密 (qqxiuzi.cn)

flag=bW9lY3Rme3czbENvbWVfVG9fbW9lQ1RGX1cyYl9jaGFsbGVuZ0UhIX0=

得到flag

03彼岸的flag

打开页面长这样，打字点发送页面有反应，用burp抓包点发送不会拦截。所以可能不存在上传，这里查看源代码

 非常简单的代码审计，得到flag           moectf{find_comments__HwdtkZ2yRpjPQlJBG0onhIg0X2lWmoy}

04cookies

打开附件，是一些api的说明

页面如图，这里先抓包

按照附件给的操作试试

这里显示用户已存在

换一个名字

 可以注册

继续按照附件操作

登录也是可以的 

多次尝试获取flag显示需要登录，这时多次出现的token引起我的注意 

---

---

这里电脑没电了，后面我又重开了环境，继续做，发现token一直是一样的

把token拿去解码

把token用burp发送一遍,发现需要admin。我们去解码网址改一下数据再传入看看

传入，得到flag:moectf{cooKi3_is_d3licious_MA9iVff90SSJ!!M6Mrfu9ifxi9i!JGofMJ36D9cPMxro}

05gas!gas!gas!

打开题目，因为条件3要求在0.5s内快速反应，初步判断要写一个脚本

import requests
import re

url = 'http://localhost:12028/'
control = 0
throttle = 2
data1 = {'driver': 'august', 'steering_control': control, 'throttle': throttle}

pattern = r'弯道(.*?)，(.*?)'

with requests.Session() as session:
    for i in range(7):  
        response = session.post(url, data=data1)
        print(response.text)
        match = re.search(pattern, response.text)
        if match:
            if match.group(1) == "向左":
                control = 1
            elif match.group(1) == "向右":
                control = -1
            else:
                control = 0

            if match.group(2) == "抓地力太小了！":
                throttle = 0
            elif match.group(2) == "抓地力太大了！":
                throttle = 2
            else:
                throttle = 1
            data1 = {'driver': 'august', 'steering_control': control, 'throttle': throttle}
            
        else:
            print("error")
            break

运行得到flag：moectf{Beautiful_Drifting!!_vsDP9tPr3e0lSCkIMVELPYYwJBEJDN-r}

06moe图床

认为是一个文件上传漏洞

查看源代码发现只准上传png结尾的文件

用burp改后缀

然后用蚁剑试试

这时不用灰心，改一下地址试试 

成功

找到flag：moectf{hmmm_improper_filter_883hLAj2HD_aK29E7lS-YAFjAK2jhdZc}

07了解你的座驾
 

弄了半天没头绪 用burp抓包看一下

xml 看起来像是一个xxe题目

试试 

得到flag：moectf{Which_one_You've_Chosen?VZzyn4IjX5cVL3mZng7FE2nfJ9d_duxM} 

我这里的代码写的有点扯淡，一次试成功了，也懒得改了

08大海捞针

题目长这样，给的很明确了

用burp爆破

 

 得到flag:moectf{script_helps_ULOZw7NrjEIKRZ4V}

09meo图床

 

打开是这样的 

这里用了会burp 和蚁剑没有结果开始认真审题。

这里用的name传参数有点想法试试

试了试没有直接给flag但是有了线索

用线索试试

一眼看去md5绕过

得到flag:moectf{oops_file_get_contents_controllable_m6Fkl9EmwKrHTPmwEw7ku8euCQ3tToyH} 

10夺命十三枪 

代码审计一下，发现unserialize php反序列化的题

打开一下给的文件看看

这段代码是一个PHP脚本，主要功能是将给定的参数传递给Hanxin.exe.php文件中的类和方法进行处理。

代码的执行流程如下：

1. 通过highlight_file函数将当前文件的源代码打印出来，相当于展示代码给用户看。
2. 引入Hanxin.exe.php文件。
3. 判断请求中是否存在"chant"参数，如果存在则将其值赋给$Chant变量，如果不存在则默认为’夺命十三枪’。
4. 创建一个Omg_It_Is_So_Cool_Bring_Me_My_Flag类的实例对象newv​isitor，并将newv​isitor，并将Chant作为参数传递进去。
5. 使用serialize函数将newv​isitor对象序列化成一个字符串，并将结果赋给newv​isitor对象序列化成一个字符串，并将结果赋给before变量。
6. 将before字符串作为参数传递给Deadly_Thirteen_Spears类的Make_a_Move方法进行处理，并将结果赋给after变量。
7. 将处理后的字符串$after打印出来，作为用户的动作反馈。
8. 使用unserialize函数尝试将$after字符串反序列化成一个对象，并打印出结果。
9. 如果出现异常（Exception），则说明代码执行过程中发生了错误，打印出相应的错误信息。

这段代码是一个PHP程序，主要用于实现两个类：Deadly_Thirteen_Spears和Omg_It_Is_So_Cool_Bring_Me_My_Flag。

首先，Deadly_Thirteen_Spears类定义了一个私有的静态成员变量Top_Secret_Long_Spear_Techniques_Manual，它是一个关联数组，包含了十三个“枪”（spear）和对应的“技巧”（movement）。Make_a_Move方法用于将传入的参数中与Top_Secret_Long_Spear_Techniques_Manual数组键匹配的部分替换为对应的值，并返回替换后的结果。

然后，Omg_It_Is_So_Cool_Bring_Me_My_Flag类定义了两个成员变量Chant和Spear_Owner，并有一个构造函数用于初始化Chant和Spear_Owner。__toString方法根据SpearO​wner的值返回不同的字符串。如果SpearO​wner的值返回不同的字符串。如果Spear_Owner不是"MaoLei"，则返回"Far away from COOL…"；否则，返回"Omg You’re So COOOOOL!!! "以及从环境变量中获取的FLAG值。

整个代码的功能是，根据传入的参数替换特定的关键词，然后根据$Spear_Owner的值返回不同的字符串。

目的是在夺命十三枪后面修改为";s:11:"Spear_Owner";s:6:"MaoLei";}，该字符串长度为35

"di_shi_san_qiang" => "Unrepentant_Lethality"每次逃逸5个字符重复7次就行

得到flag：moectf{C00L_b0Y!_56MXZcV8BDqE8Zxn0LkEMGEIHs1HXz7m}

11signin

 

点了没反应抓包一下看看

看起来像base64编码

解码5次后

 猜测是改admin

有个附件打开看看

from secrets import users, salt
import hashlib
import base64
import json
import http.server

with open("flag.txt","r") as f:
    FLAG = f.read().strip()

def gethash(*items):
    c = 0
    for item in items:
        if item is None:
            continue
        c ^= int.from_bytes(hashlib.md5(f"{salt}[{item}]{salt}".encode()).digest(), "big") # it looks so complex! but is it safe enough?
    return hex(c)[2:]

assert "admin" in users
assert users["admin"] == "admin"

hashed_users = dict((k,gethash(k,v)) for k,v in users.items())

eval(int.to_bytes(0x636d616f686e69656e61697563206e6965756e63696165756e6320696175636e206975616e6363616361766573206164^8651845801355794822748761274382990563137388564728777614331389574821794036657729487047095090696384065814967726980153,160,"big",signed=True).decode().translate({ord(c):None for c in "\x00"})) # what is it?
    
def decrypt(data:str):
        for x in range(5):
            data = base64.b64encode(data).decode() # ummm...? It looks like it's just base64 encoding it 5 times? truely?
        return data

__page__ = base64.b64encode("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")
        
class MyHandler(http.server.BaseHTTPRequestHandler):
    def do_GET(self):
        try:
            if self.path == "/":
                self.send_response(200)
                self.end_headers()
                self.wfile.write(__page__)
            else:
                self.send_response(404)
                self.end_headers()
                self.wfile.write(b"404 Not Found")
        except Exception as e:
            print(e)
            self.send_response(500)
            self.end_headers()
            self.wfile.write(b"500 Internal Server Error")

    def do_POST(self):
        try:
            if self.path == "/login":
                body = self.rfile.read(int(self.headers.get("Content-Length")))
                payload = json.loads(body)
                params = json.loads(decrypt(payload["params"]))
                print(params)
                if params.get("username") == "admin":
                    self.send_response(403)
                    self.end_headers()
                    self.wfile.write(b"YOU CANNOT LOGIN AS ADMIN!")
                    print("admin")
                    return
                if params.get("username") == params.get("password"):
                    self.send_response(403)
                    self.end_headers()
                    self.wfile.write(b"YOU CANNOT LOGIN WITH SAME USERNAME AND PASSWORD!")
                    print("same")
                    return
                hashed = gethash(params.get("username"),params.get("password"))
                for k,v in hashed_users.items():
                    if hashed == v:
                        data = {
                            "user":k,
                            "hash":hashed,
                            "flag": FLAG if k == "admin" else "flag{YOU_HAVE_TO_LOGIN_IN_AS_ADMIN_TO_GET_THE_FLAG}"
                        }
                        self.send_response(200)
                        self.end_headers()
                        self.wfile.write(json.dumps(data).encode())
                        print("success")
                        return
                self.send_response(403)
                self.end_headers()
                self.wfile.write(b"Invalid username or password")
            else:
                self.send_response(404)
                self.end_headers()
                self.wfile.write(b"404 Not Found")
        except Exception as e:
            print(e)
            self.send_response(500)
            self.end_headers()
            self.wfile.write(b"500 Internal Server Error")

if __name__ == "__main__":
    server = http.server.HTTPServer(("", 9999), MyHandler)
    server.serve_forever()

然后我当时做的时候{"username":"admin","password":"admin"} 觉得肯定要改admin

然后试了试成功了

这里先将admin和admin全改成1，然后

改成 {"username":"1","password":"2"}

 试了几次发现改成 {"username":"1","password":1}可以得到flag：moectf{C0nGUrAti0ns!_y0U_hAve_sUCCessFUlly_siGnin!_iYlJf!M3rux9G9Vf!Jox}

 

 12出去旅游的心海

这题一觉起来比赛结束了，找不到环境了，大概口述一下，等能复现了补上，

sql注入，先f12，会得到一个.php,打开可以看到代码

代码是网上搜的

connect_errno) {
    echo '数据库连接失败: ' . $mysqli->connect_error;
    exit();
}

$query = "INSERT INTO visitor_records (ip, user_agent, time) VALUES ('$ip', '$user_agent', $time)";

// 执行插入
$result = mysqli_query($mysqli, $query);

// 检查插入是否成功
if ($result) {
    echo '数据插入成功';
} else {
    echo '数据插入失败: ' . mysqli_error($mysqli);
}

// 关闭数据库连接
mysqli_close($mysqli);

像是一个显错注入，用updatamxl试试，用sqlmap也行，但是我sqlmap有点问题

查表名库名等后

1 and updatexml(1,substring(concat(0x7e,(select group_concat(content,0x7e,id) from secret_of_kokomi)),30,40),1)

大概代码就是这种就可以得到flag