TryHackMe: Learn Linux

[Task 1] Intro

[Task 2] Methodology

[Task 3] [Section 1: SSH] — Intro

[Task 4] [Section 1: SSH] — Putty and ssh

1. Download Putty here:
   https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

Or using linux

apt install putty

2. Login using Putty

username: shiba1

Enter username, ip and click Open

Click Accept

Enter password “shiba1”

3. Login using command line in linux or windows

ssh <username>@<ip>

[Task 5] [Section 2: Running Commands] — Basic Command Execution

echo  hello

[Task 6] [Section 2: Running Commands] — Manual Pages and Flags

1. How would you output hello without a newline

man echo

echo -n hello

[Task 7] [Section 3: Basic File Operations] — ls

1. What flag outputs all entries

ls -a

2. What flag outputs things in a “long list” format

ls -l

[Task 8] [Section 3: Basic File Operations] — cat

1. What flag numbers all output lines?

cat --help

[Task 9] [Section 3: Basic File Operations] — touch

touch b.txt
ls

[Task 10] [Section 3: Basic File Operations] — Running A Binary

1. How would you run a binary called hello using the directory shortcut . ?

./hello

2. How would you run a binary called hello in your home directory using the shortcut ~ ?

~/hello

3. How would you run a binary called hello in the previous directory using the shortcut .. ?

../hello

[Task 11] Binary — Shiba1

1. What’s the password for shiba2

touch noot.txt
./shiba1

[Task 12] su

1. How do you specify which shell is used when you login?

su --help

[Task 13] [Section 4 — Linux Operators]: Intro

su shiba2

[Task 14] [Section 4: Linux Operators]: “>”

1. How would you output twenty to a file called test

echo twenty > test

ls 
cat test

[Task 15] [Section 4: Linux Operators]: “>>”

echo hello > file
cat file

echo noot >> file
cat file

[Task 16] [Section 4: Linux Operators]: “&&”

echo hello >> file2 && cat file2

[Task 17] [Section 4: Linux Operators]: “&”

Let’s open GUI app on my machine

try without “&”

Press “Enter”, You can see that you can not type any command.

try with “&” and Press “Enter”. You can type any command after it.

[Task 18] [Section 4: Linux Operators]: “$”

echo $USER

mkdir tmpdir
cd tmpdir
touch $USER
ls

touch $USER
echo hi >> $USER
cat shiba2

1. How would you set nootnoot equal to 1111

export nootnoot=1111
echo $nootnoot

2. What is the value of the home environment variable

echo $HOME

[Task 19] [Section 4: Linux Operators]: “|”

Let’s try with “passwd”

cat /etc/passwd

There’re string “noot”

Let’s try with “|”

cat /etc/passwd | grep noot

[Task 20] [Section 4: Linux Operators] — “;”

sdasdasdsa; ls

[Task 21] Binary — shiba2

1. What is shiba3’s password

Let’s run “shiba2” first.

./shiba2

Error!!!

Export variable “test1234”

export test1234=$USER
./shiba2

[Task 22] [Section 5 — Advanced File Operations]: Intro

su shiba3

[Task 23] [Section 5 — Advanced File Operators]: A bit of background.

[Task 24] [Section 5: Advanced File Operations]: chmod

[Task 25] [Section 5: Advanced File Operations] — chown

1. How would you change the owner of file to paradox
   ANS: chown <owner> file
2. What about the owner and the group of file to paradox
   ANS: chown <owner>:<group> file
3. What flag allows you to operate on every file in the directory at once?
   ANS: -r

[Task 26] [Section 5: Advanced File Operations] — rm

rm --help

[Task 27] [Section 5: Advanced File Operations] — mv

1. How would you move file to /tmp
   ANS: mv file ****

[Task 28] [Section 5: Advanced File Operations] — cp

echo test > testfile
cp testfile testfile2

[Task 29] [Section 5: Advanced file Operations] — cd && mkdir

1. Using relative paths, how would you cd to your home directory.
   ANS: cd ~
2. Using absolute paths how would you make a directory called test in /tmp
   ANS: mkdir /tmp/test

[Task 30] [Section 5: Advanced File Operations] ln

Let’s try the command

echo hello > hello
cat hello

ln hello hellohardlink
ls
cat hellohardlink

echo cat >> hellohardlink
cat hellohardlink
cat hello

1. How would I link /home/test/testfile to /tmp/test
   ANS: ln /home/test/testfile /tmp/test

[Task 31] [Section 5 — Advanced File Operations]: find

1. How do you find files that have specific permissions?
   ANS: -per*
2. How would you find all the files in /home
   ANS: find <path>
3. How would you find all the files owned by paradox on the whole system
   ANS: find / -user <username>

[Task 32] [Section 5: Advanced File Operations] — grep

1. What flag lists line numbers for every string found?
   ANS: -n
2. How would I search for the string boop in the file aaaa in the directory /tmp
   ANS: grep boop <path>

[Task 33] Binary — Shiba3

1. What is shiba4’s password

find / -name shiba4 | grep shiba4 | grep shiba4

cd /opt/secret
./shiba4

[Task 34] [Section 6: Miscellaneous]: Intro

su shiba4

[Task 35] [Section 6: Miscellaneous]: sudo

1. How do you specify which user you want to run a command as.
   ANS: -u
2. How would I run whoami as user jen?
   ANS: sudo -u jen <command>
3. How do you list your current sudo privileges(what commands you can run, who you can run them as etc.)
   ANS: -l

[Task 36] [Section 6: Miscellaneous]: Adding users and groups

1. How would I add the user test to the group test
   ANS: sudo usermod -a -G <user> <group>

[Task 37] [Section 6: Miscellaneous]: nano

Let’s try open nano

nano <filename>

[Task 38] [Section 6: Miscellaneous]: Basic shell scripting

nano s.sh

In nano

echo hello
echo whoami
whoami

run the script

bash s.sh

add “#!/bin/bash”

nano s.sh

In nano

#!/bin/bash
echo hello
echo whoami
whoami

edit from s.sh to s

mv s.sh s
ls

edit permission

chmod 777 s

run the script

./s

[Task 39] [Section 6: Miscellaneous]: Important Files and Directories

[Task 40] [Section 6 — Miscellaneous]: Installing packages(apt)

[Task 41] [Section 6: Miscellaneous]: Processes

List the processes

ps

[Task 42] Fin ~

[Task 43] Bonus Challenge — The True Ending

Let’s search through each user’s files.

find / -user <username> -type f 2>>/dev/null

cat /var/log/test1234

Permission Denied!!!

ls -l /var/log/test1234

It’s belong to shiba2

su shiba2
cat /var/log/test1234

su nootnoot

Check if nootnoot can run sudo

sudo -l

nootnoot can run sudo command

sudo cat /root/root.txt