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Hack The Box: Beep

Beep - 10.10.10.7

Target enumeration:

OS: Linux IP: 10.10.10.7

User: aeff3def0c765c2677b94715cffa73ac

Root: d88e006123842106982acce0aaf453f0

Ports / Services / Software versions running

22/tcp    open  ssh        OpenSSH 4.3 (protocol 2.0)

25/tcp    open  smtp       Postfix smtpd

80/tcp    open  http       Apache httpd 2.2.3

110/tcp   open  pop3       Cyrus pop3d 2.3.7-Invoca-RPM-2.3.7-7.el5_6.4

111/tcp   open  rpcbind    2 (RPC #100000)

143/tcp   open  imap       Cyrus imapd 2.3.7-Invoca-RPM-2.3.7-7.el5_6.4

443/tcp   open  ssl/http   Apache httpd 2.2.3 ((CentOS))

993/tcp   open  ssl/imap   Cyrus imapd

995/tcp   open  pop3       Cyrus pop3d

3306/tcp  open  mysql      MySQL (unauthorized)

4445/tcp  open  upnotifyp?

10000/tcp open  http       MiniServ 1.570 (Webmin httpd)

Vulnerability exploited:

This attack exploits FreePBX version 2.10.0,2.9.0 and possibly older. Due to the way callme_page.php handles the 'callmenum' parameter, it is possible to inject code to the '$channel' variable in function callme_startcall in order to gain remote code execution. Please note in order to use this module properly, you must know the extension number, which can be enumerated or bruteforced, or you may try some of the default extensions such as 0 or 200.

Also, the call has to be answered (or go to voice). Tested on both Elastix and FreePBX ISO image installs.

Privilege escalation.

User is allowed to run an old version of nmap --interactive using sudo which can then drop the low privileged user into a root shell.

Exploiting the host:

Nmap

Port 443 is running elastix which has a common vulnerability.

Set up unix/http/freepbx_callmenum with the following options in metasploit.

Execute the exploit and wait a while as it runs. After a while you will get a shell.

Interact with the session and start enumerating the machine.

Unusual entry in sudo -l

Use sudo nmap --interactive to get root.