【华东南AWDP】第十七届全国大学生信息安全竞赛 CISCN 2024 创新实践能力赛区域赛 部分题解WP

Jay 172024-06-23 20:46

前言：这次区域赛AWDP安恒作为支持，赛制风格遵循安恒，一小时check一次。室温35°在室内坐了8小时，午饭是藿香正气水拌冰水。这场总体下来中规中矩吧。

WEB-welcome-BREAK

Ctrl+U拿到flag

WEB-submit-BREAK

文件上传，简单绕过

绕过就两个，一个MIMA头，一个等号换php（短标签）

WEB-submit-FIX

修两个点，一个是后缀检验，一个是waf增加

php 复制代码 
<?php
// $path = "./uploads";
error_reporting(0);
$path = "./uploads";
$content = file_get_contents($_FILES['myfile']['tmp_name']);
$allow_content_type = array("image/png");
$type = $_FILES["myfile"]["type"];
if (!in_array($type, $allow_content_type)) {
    die("只允许png哦!<br>");
}

//修改点1
$allow_ext = array(".png");
$file_name=$_FILES["myfile"]['name'];
$_FILES["myfile"]['name'] = str_replace(".ph","",$_FILES["myfile"]['name']);
$file_ext = strrchr($file_name, '.');
$file_ext = strtolower($file_ext); //转换为小写
$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA
$file_ext = trim($file_ext); //收尾去空
if (!in_array($file_ext, $allow_ext)) {
    die("只允许png哦!<br>");
}

//修改点2
if (preg_match('/(php|script|xml|user|htaccess|\<\?|\<\?\=|eval|system|assert|fllllagg|f\*|\/f|cat|POST|GET|\$\_|exec)/i', $content)) {
    // echo "匹配成功!";
    die('鼠鼠说你的内容不符合哦0-0');
} else {
    $file = $path . '/' . $_FILES['myfile']['name'];
    echo $file;

    if (move_uploaded_file($_FILES['myfile']['tmp_name'], $file)) {
        file_put_contents($file, $content);
        echo 'Success!<br>';
    } else {
        echo 'Error!<br>';
    }
}
?>

WEB-粗心的程序员-BREAK

www.zip源码泄露。简单代码审计和逻辑漏洞

简单扫一眼，开了sql的PDO（但是最后没用上）

主要漏洞文件：

贴一下代码：

php 复制代码 
<?php
error_reporting(0);
include "default_info_auto_recovery.php";
session_start();
$p = $_SERVER["HTTP_X_FORWARDED_FOR"]?:$_SERVER["REMOTE_ADDR"];
if (preg_match("/\?|php|:/i",$p))
{
    die("");
}
$time = date('Y-m-d h:i:s', time());
$username = $_SESSION['username'];
$id = $_SESSION['id'];
if ($username && $id){
    echo "Hello,"."$username";
    $str = "//登陆时间$time,$username $p";
    $str = str_replace("\n","",$str);
    file_put_contents("config.php",file_get_contents("config.php").$str);
}else{
    die("NO ACCESS");
}
?>
<br>
<script type="text/javascript" src="js/jquery-1.9.0.min.js"></script>
<script type="text/javascript" src="js/jquery.base64.js"></script>
<script>
    function submitData(){
        var obj = new Object();
        obj.name = $('#newusername').val();
        var str = $.base64.encode(JSON.stringify(obj.name).replace("\"","").replace("\"",""));
        $.post("edit.php",
            {
                newusername: str
            },
            function(str){
                alert(str);
                location.reload()
            });
    }

    jQuery.base64 = (function($) {

        var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

        function utf8Encode(string) {
            string = string.replace(/\r\n/g,"\n");
            var utftext = "";
            for (var n = 0; n < string.length; n++) {
                var c = string.charCodeAt(n);
                if (c < 128) {
                    utftext += String.fromCharCode(c);
                }
                else if((c > 127) && (c < 2048)) {
                    utftext += String.fromCharCode((c >> 6) | 192);
                    utftext += String.fromCharCode((c & 63) | 128);
                }
                else {
                    utftext += String.fromCharCode((c >> 12) | 224);
                    utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                    utftext += String.fromCharCode((c & 63) | 128);
                }
            }
            return utftext;
        }

        function encode(input) {
            var output = "";
            var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
            var i = 0;
            input = utf8Encode(input);
            while (i < input.length) {
                chr1 = input.charCodeAt(i++);
                chr2 = input.charCodeAt(i++);
                chr3 = input.charCodeAt(i++);
                enc1 = chr1 >> 2;
                enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                enc4 = chr3 & 63;
                if (isNaN(chr2)) {
                    enc3 = enc4 = 64;
                } else if (isNaN(chr3)) {
                    enc4 = 64;
                }
                output = output +
                    keyStr.charAt(enc1) + keyStr.charAt(enc2) +
                    keyStr.charAt(enc3) + keyStr.charAt(enc4);
            }
            return output;
        }

        return {
            encode: function (str) {
                return encode(str);
            }
        };

    }(jQuery));

</script>
更改用户名<input type="text" name="newusername" id="newusername" value="">
<button type="submit" onclick="submitData()" >更改</button>

简单说一下思路

1、$str = "//登陆时间$time,$username $p";会被写入php文件file_put_contents("config.php",file_get_contents("config.php").$str);

2、既然是php，写入了如果不是算注释的话就能执行

3、尝试写🐎

4、用户名这边利用?>进行截断注释的作用

5、$p这边进行写🐎

WEB-粗心的程序员-FIX

源码如下

php 复制代码 
<?php
error_reporting(0);
include "default_info_auto_recovery.php";
session_start();
$p = $_SERVER["HTTP_X_FORWARDED_FOR"]?:$_SERVER["REMOTE_ADDR"];
if (preg_match("/\?|php|:/i",$p))
{
    die("");
}
$time = date('Y-m-d h:i:s', time());
$username = $_SESSION['username'];
$id = $_SESSION['id'];
if ($username && $id){
    echo "Hello,"."$username";
    $str = "//登陆时间$time,$username $p";
    $str = str_replace("\n","",$str);
    file_put_contents("config.php",file_get_contents("config.php").$str);
}else{
    die("NO ACCESS");
}
?>
<br>
<script type="text/javascript" src="js/jquery-1.9.0.min.js"></script>
<script type="text/javascript" src="js/jquery.base64.js"></script>
<script>
    function submitData(){
        var obj = new Object();
        obj.name = $('#newusername').val();
        var str = $.base64.encode(JSON.stringify(obj.name).replace("\"","").replace("\"",""));
        $.post("edit.php",
            {
                newusername: str
            },
            function(str){
                alert(str);
                location.reload()
            });
    }

    jQuery.base64 = (function($) {

        var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

        function utf8Encode(string) {
            string = string.replace(/\r\n/g,"\n");
            var utftext = "";
            for (var n = 0; n < string.length; n++) {
                var c = string.charCodeAt(n);
                if (c < 128) {
                    utftext += String.fromCharCode(c);
                }
                else if((c > 127) && (c < 2048)) {
                    utftext += String.fromCharCode((c >> 6) | 192);
                    utftext += String.fromCharCode((c & 63) | 128);
                }
                else {
                    utftext += String.fromCharCode((c >> 12) | 224);
                    utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                    utftext += String.fromCharCode((c & 63) | 128);
                }
            }
            return utftext;
        }

        function encode(input) {
            var output = "";
            var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
            var i = 0;
            input = utf8Encode(input);
            while (i < input.length) {
                chr1 = input.charCodeAt(i++);
                chr2 = input.charCodeAt(i++);
                chr3 = input.charCodeAt(i++);
                enc1 = chr1 >> 2;
                enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                enc4 = chr3 & 63;
                if (isNaN(chr2)) {
                    enc3 = enc4 = 64;
                } else if (isNaN(chr3)) {
                    enc4 = 64;
                }
                output = output +
                    keyStr.charAt(enc1) + keyStr.charAt(enc2) +
                    keyStr.charAt(enc3) + keyStr.charAt(enc4);
            }
            return output;
        }

        return {
            encode: function (str) {
                return encode(str);
            }
        };

    }(jQuery));

</script>
更改用户名<input type="text" name="newusername" id="newusername" value="">
<button type="submit" onclick="submitData()" >更改</button>

username和p加waf就行，怎么打的怎么加

php 复制代码 
<?php
error_reporting(0);
include "default_info_auto_recovery.php";
session_start();
$p = $_SERVER["HTTP_X_FORWARDED_FOR"]?:$_SERVER["REMOTE_ADDR"];
//waf1
if (preg_match("/\?|php|:|system|cat|flaaaaaag|\*|eval|php/i",$p))
{
    die("");
}
$time = date('Y-m-d h:i:s', time());
$username = $_SESSION['username'];
$id = $_SESSION['id'];
//waf2
if (preg_match("/\?|\<\?|php|:/i",$username))
{
    die("");
}

if ($username && $id){
    echo "Hello,"."$username";
    $str = "//登陆时间$time,$username $p";
    $str = str_replace("\n","",$str);
    file_put_contents("config.php",file_get_contents("config.php").$str);
}else{
    die("NO ACCESS");
}
?>
<br>
<script type="text/javascript" src="js/jquery-1.9.0.min.js"></script>
<script type="text/javascript" src="js/jquery.base64.js"></script>
<script>
    function submitData(){
        var obj = new Object();
        obj.name = $('#newusername').val();
        var str = $.base64.encode(JSON.stringify(obj.name).replace("\"","").replace("\"",""));
        $.post("edit.php",
            {
                newusername: str
            },
            function(str){
                alert(str);
                location.reload()
            });
    }

    jQuery.base64 = (function($) {

        var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

        function utf8Encode(string) {
            string = string.replace(/\r\n/g,"\n");
            var utftext = "";
            for (var n = 0; n < string.length; n++) {
                var c = string.charCodeAt(n);
                if (c < 128) {
                    utftext += String.fromCharCode(c);
                }
                else if((c > 127) && (c < 2048)) {
                    utftext += String.fromCharCode((c >> 6) | 192);
                    utftext += String.fromCharCode((c & 63) | 128);
                }
                else {
                    utftext += String.fromCharCode((c >> 12) | 224);
                    utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                    utftext += String.fromCharCode((c & 63) | 128);
                }
            }
            return utftext;
        }

        function encode(input) {
            var output = "";
            var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
            var i = 0;
            input = utf8Encode(input);
            while (i < input.length) {
                chr1 = input.charCodeAt(i++);
                chr2 = input.charCodeAt(i++);
                chr3 = input.charCodeAt(i++);
                enc1 = chr1 >> 2;
                enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                enc4 = chr3 & 63;
                if (isNaN(chr2)) {
                    enc3 = enc4 = 64;
                } else if (isNaN(chr3)) {
                    enc4 = 64;
                }
                output = output +
                    keyStr.charAt(enc1) + keyStr.charAt(enc2) +
                    keyStr.charAt(enc3) + keyStr.charAt(enc4);
            }
            return output;
        }

        return {
            encode: function (str) {
                return encode(str);
            }
        };

    }(jQuery));

</script>
更改用户名<input type="text" name="newusername" id="newusername" value="">
<button type="submit" onclick="submitData()" >更改</button>

WEB-Polluted-FIX

攻击时候没打出来

原来代码

python 复制代码 
from flask import Flask, session, redirect, url_for,request,render_template
import os
import hashlib
import json
import re

def generate_random_md5():
    random_string = os.urandom(16)
    md5_hash = hashlib.md5(random_string)

    return md5_hash.hexdigest()
def filter(user_input):
    blacklisted_patterns = ['init', 'global', 'env', 'app', '_', 'string']
    for pattern in blacklisted_patterns:
        if re.search(pattern, user_input, re.IGNORECASE):
            return True
    return False
def merge(src, dst):
    # Recursive merge function
    for k, v in src.items():
        if hasattr(dst, '__getitem__'):
            if dst.get(k) and type(v) == dict:
                merge(v, dst.get(k))
            else:
                dst[k] = v
        elif hasattr(dst, k) and type(v) == dict:
            merge(v, getattr(dst, k))
        else:
            setattr(dst, k, v)


app = Flask(__name__)
app.secret_key = generate_random_md5()

class evil():
    def __init__(self):
        pass

@app.route('/',methods=['POST'])
def index():
    username = request.form.get('username')
    password = request.form.get('password')

    session["username"] = username
    session["password"] = password
    Evil = evil()
    if request.data:
        if filter(str(request.data)):
            return "NO POLLUTED!!!YOU NEED TO GO HOME TO SLEEP~"
        else:
            merge(json.loads(request.data), Evil)
            return "MYBE YOU SHOULD GO /ADMIN TO SEE WHAT HAPPENED"
    return render_template("index.html")

@app.route('/admin',methods=['POST', 'GET'])
def templates():
    username = session.get("username", None)
    password = session.get("password", None)
    if username and password:
        if username == "adminer" and password == app.secret_key:
            return render_template("important.html", flag=open("/flag", "rt").read())
        else:
            return "Unauthorized"
    else:
        return f'Hello,  This is the POLLUTED page.'

if __name__ == '__main__':
    app.run(host='0.0.0.0',debug=True, port=80)

修复代码

python 复制代码 
from flask import Flask, session, redirect, url_for,request,render_template
import os
import hashlib
import json
import re

def generate_random_md5():
    random_string = os.urandom(16)
    md5_hash = hashlib.md5(random_string)

    return md5_hash.hexdigest()
def filter(user_input):
    #修复点1 加waf
    blacklisted_patterns = ['init', 'global', 'env', 'app', 'secret', 'key', 'admin','string', 'proto', 'constructor', 'insert', 'update', 'truncate', 'drop', 'create','doc','str', '_']
    for pattern in blacklisted_patterns:
        if re.search(pattern, user_input, re.IGNORECASE):
            return True
    return False

def merge(src, dst):
    # Recursive merge function
    for k, v in src.items():
        if hasattr(dst, '__getitem__'):
            if dst.get(k) and type(v) == dict:
                merge(v, dst.get(k))
            else:
                dst[k] = v
        elif hasattr(dst, k) and type(v) == dict:
            merge(v, getattr(dst, k))
        else:
            setattr(dst, k, v)


app = Flask(__name__)
app.secret_key = generate_random_md5()

class evil():
    def __init__(self):
        pass

@app.route('/',methods=['POST'])
def index():
    username = request.form.get('username')
    password = request.form.get('password')

    #修复点二，乱加的
    if username=='adminer':
        exit(0)
    if username=='admin':
        exit(0)

    session["username"] = username
    session["password"] = password
    Evil = evil()
    if request.data:
        if filter(str(request.data)):
            return "NO POLLUTED!!!YOU NEED TO GO HOME TO SLEEP~"
        else:
            #其实直接ban了这个就行
            merge(json.loads(request.data), Evil)
            return "MYBE YOU SHOULD GO /ADMIN TO SEE WHAT HAPPENED"
    return render_template("index.html")

@app.route('/admin',methods=['POST', 'GET'])
def templates():
    username = session.get("username", None)
    password = session.get("password", None)
    if username and password:
        #修复点三，black一下
        if username == "adminerrrr" and password == app.secret_key:
            return render_template("important.html", flag=open("/flag", "rt").read())
        else:
            return "Unauthorized"
    else:
        return f'Hello,  This is the POLLUTED page.'

if __name__ == '__main__':
    app.run(host='0.0.0.0',debug=True, port=80)

PWN-ezwp-BREAK

打开网页直接搜索flag，非预期闹麻了

PWN-CJS0N-FIX

直接将printf改成puts即可

PWN-printf-master-FIX

同样将printf改成puts即可

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