> For the complete documentation index, see [llms.txt](https://0xmedhat.gitbook.io/whoami/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://0xmedhat.gitbook.io/whoami/writesup/hacked-cyberdefenders.md). # Hacked Cyberdefenders * [Details](https://cyberdefenders.org/blueteam-ctf-challenges/71#nav-overview) You have been called to analyze a compromised Linux web server. Figure out how the threat actor gained access, what modifications were applied to the system, and what persistent techniques were utilized. (e.g. backdoors, users, sessions, etc). * [Questions](https://cyberdefenders.org/blueteam-ctf-challenges/71#nav-questions) #### Q1 What is the system timezone? We Can found it the `/etc/timezone` file

**Ans : Europe/Brussels** #### Q2 Who was the last user to log in to the system? We can find it in auth file on: `/var/log/auth.log`

57708Accepted password for mail from 192.168.210.131 port 57708 ssh2

**Ans : mail** #### Q3 What was the source port the user 'mail' connected from? from the priv screen we can found it the answer **"57708"** #### Q4 How long was the last session for user 'mail'? (Minutes only)

We can found the last session started at 13:23:34 and finished at 13:24:11\ then it's just 1 minute \ **Ans : 1** #### Q5 Which server service did the last user use to log in to the system? in the last screen we can found **sshd** **Ans : sshd** #### Q6 What type of authentication attack was performed against the target machine

In the same file We found it's many failled attemped okay it's bruteforce! **Ans : brute-force** **Q7 How many IP addresses are listed in the '/var/log/lastlog' file?**

**Ans : 2** #### Q8 How many users have a login shell? Users Having shell using **/bin/bash**

**Ans : 5** #### Q9 What is the password of the mail user? We can found password of email user in /etc/shadow

``` sudo john --wordlist==/usr/share/rockyou.txt passwd.txt ```

**Ans : forensics** #### Q10 Which user account was created by the attacker? Back to auth.log \ searching for useradd command we can found it

**Ans : php** #### Q11 How many user groups exist on the machine? we can found group in `etc/group` open it to count

**Ans : 58** #### Q12 How many users have sudo access? in the same file searching for sudo

**Ans : 2** #### Q13 What is the home directory of the PHP user? From Q10 When the attacker created the user PHP, its home directory was /usr/php **Ans : /usr/php** #### Q14 What command did the attacker use to gain root privilege? (Answer contains two spaces). We know from the prev Qusetions that the attacker logged in as the user mail , we find the it's home direcotry at: /var/mail let's investigate it's bash history

**Ans : sudo su -** #### #### Q15 Which file did the user 'root' delete? let's check root’s bash history file

**Ans : 37292.c** #### Q16 Recover the deleted file, open it and extract the exploit author name. After some minutes I searching in /tmp After i clicked on it Window defender running ")

After that search for the CVE in exploit-db:

\ **Ans : rebel** #### Q17 What is the content management system (CMS) installed on the machine? it's found in etc

**Ans : drupal** #### Q18 What is the version of the CMS installed on the machine? By helping of chatgpt we can found the version of Drupal Cms in info files found in /var/www/html/

**Ans : 7.26** #### Q19 Which port was listening to receive the attacker's reverse shell? From the question 6 we can found the attacker ip [192.168.210.131](http://192.168.210.131/) we can go to access.log and grep it we found decoded post request

let's going to cyberchief

**Ans : 4444** We fininsed , Thank UUUUUUU for reading ❤🥰