image-20250306192629923

[!Important]

RCE_preg_match绕过及RCE重定向截断

0x01

访问靶场,回显源码

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<?php

/*
# -*- coding: utf-8 -*-
# @Author: h1xa
# @Date:   2020-09-05 20:49:30
# @Last Modified by:   h1xa
# @Last Modified time: 2020-09-05 21:32:51
# @email: h1xa@ctfer.com
# @link: https://ctfer.com

*/


if(isset($_GET['c'])){
    $c=$_GET['c'];
    if(!preg_match("/\;|cat/i", $c)){
        system($c." >/dev/null 2>&1");
    }
}else{
    highlight_file(__FILE__);
}

0x02

[!Note]

代码审计

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if(!preg_match("/\;|cat/i", $c)){
        system($c." ");
    }

过滤字段; cat

且将输出结果重定向

故构造payload思路为绕过cat ;且截断 >/dev/null 2>&1

0X03

payload尝试过程与Web42相同,不再赘述

image-20250306193531417