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THM | Linux PrivEsc

· 4 min read

Shells and Privilege Escalation | Linux PrivEsc | Summary:

This series of walkthroughs aims to help out complete beginners with finishing the Complete Beginner path on the TryHackMe website. It is based on the learning content provided in the Linux PrivEsc room.


Disclaimer: Please note that this write-up is NOT intended to replace the original room or its content, but rather serve as supplementary material for those who are stuck and need additional guidance.

01 | Deploy the Vulnerable Debian VM

Question 1: Deploy the machine and login to the "user" account using SSH.

No answer needed

Question 2: Run the "id" command. What is the result?

uid=1000(user) gid=1000(user) groups=1000(user),24(cdrom),25(floppy),29(audio),30(dip),44(video),46(plugdev)

02 | Service Exploits

Question 1: Read and follow along with the above.

No answer needed

03 | Weak File Permissions - Readable /etc/shadow

Question 1: What is the root user's password hash?

$6$Tb/euwmK$OXA.dwMeOAcopwBl68boTG5zi65wIHsc84OWAIye5VITLLtVlaXvRDJXET..it8r.jbrlpfZeMdwD3B0fGxJI0

Question 2: What hashing algorithm was used to produce the root user's password hash?

sha512crypt

Question 3: What is the root user's password?

password123

04 | Weak File Permissions - Writable /etc/shadow

Question 1: Read and follow along with the above.

No answer needed

05 | Weak File Permissions - Writable /etc/passwd

Question 1: Run the "id" command as the newroot user. What is the result?

uid=0(root) gid=0(root) groups=0(root)

06 | Sudo - Shell Escape Sequences

Question 1: How many programs is "user" allowed to run via sudo?

11

Question 2: One program on the list doesn't have a shell escape sequence on GTFOBins. Which is it?

apache2

Question 3: Consider how you might use this program with sudo to gain root privileges without a shell escape sequence.

No answer needed

07 | Sudo - Environment Variables

Question 1: Read and follow along with the above.

No answer needed

08 | Cron Jobs - File Permissions

Question 1: Read and follow along with the above.

No answer needed

09 | Cron Jobs - PATH Environment Variable

Question 1: What is the value of the PATH variable in /etc/crontab?

/home/user:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

10 | Cron Jobs - Wildcards

Question 1: Read and follow along with the above.

No answer needed

11 | SUID / SGID Executables - Known Exploits

Question 1: Read and follow along with the above.

No answer needed

12 | SUID / SGID Executables - Shared Object Injection

Question 1: Read and follow along with the above.

No answer needed

13 | SUID / SGID Executables - Environment Variables

Question 1: Read and follow along with the above.

No answer needed

14 | SUID / SGID Executables - Abusing Shell Features (#1)

Question 1: Read and follow along with the above.

No answer needed

15 | SUID / SGID Executables - Abusing Shell Features (#2)

Question 1: Read and follow along with the above.

No answer needed

16 | Passwords & Keys - History Files

Question 1: What is the full mysql command the user executed?

mysql -h somehost.local -uroot -ppassword123

17 | Passwords & Keys - Config Files

Question 1: What file did you find the root user's credentials in?

/etc/openvpn/auth.txt

18 | Passwords & Keys - SSH Keys

Question 1: Read and follow along with the above.

No answer needed

19 | NFS

Question 1: What is the name of the option that disables root squashing?

no_root_squash

20 | Kernel Exploits

Question 1: Read and follow along with the above.

No answer needed

21 | Privilege Escalation Scripts

Question 1: Experiment with all three tools, running them with different options. Do all of them identify the techniques used in this room?

No answer needed