image-20250308210512826

[!Important]

preg_match过滤绕过及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 22:22:43
# @email: h1xa@ctfer.com
# @link: https://ctfer.com

*/


if(isset($_GET['c'])){
    $c=$_GET['c'];
    if(!preg_match("/\;|cat|flag| |[0-9]|\\$|\*|more|less|head|sort|tail|sed|cut|awk|strings|od|curl|\`|\%/i", $c)){
        system($c." >/dev/null 2>&1");
    }
}else{
    highlight_file(__FILE__);
}

0x02

过滤字段新增%,由于此前的payload中包含的%在url编码时会被自动解析,故无影响,payload同上不再赘述。