Linux 101⚓︎
Difficulty:
Direct link: https://hhc23-wetty.holidayhackchallenge.com?challenge=linux101
Objective⚓︎
Request
Visit Ginger Breddie in Santa's Shack on Christmas Island to help him with some basic Linux tasks. It's in the southwest corner of Frosty's Beach.
Ginger Breddie
Hey, welcome to Santa's Surf Shack on tropical Christmas Island! I'm just hanging ten here, taking it easy while brushing up on my Linux skills. You ever tried getting into Linux? It's a super cool way to play around with computers. Can you believe ChatNPT suggested this trip to the Geese Islands this year? I'm so thrilled! Kudos to ChatNPT, eh? The sunshine, the waves, and my surfboard – simply loving it! So, what do you have planned? Care to join me in a Linux session?
Solution⚓︎
Clicking on the "Linux 101" terminal besides Ginger Breddie opens a terminal window. The top part shows instructions, while the middle part is a normal shell prompt. At the bottom, a growing bar of presents show our progress.
We'll show the instructions, our commands and their output (if any) in this table:
| Instruction | Command(s) | Output |
|---|---|---|
| The North Pole 🎁 Present Maker:All the presents on this system have been stolen by trolls. Capture trolls by following instructions here and 🎁's will appear in the green bar below. Run the command "hintme" to receive a hint. | yes | |
| Perform a directory listing of your home directory to find a troll and retrieve a present! | ls | HELP troll_19315479765589239 workshop |
| Now find the troll inside the troll. | cat troll_19315479765589239 | troll_24187022596776786 |
| Great, now remove the troll in your home directory. | rm troll_19315479765589239 | |
| Print the present working directory using a command. | pwd | /home/elf |
| Good job but it looks like another troll hid itself in your home directory. Find the hidden troll! | ls -a | . .. .bash_history .bash_logout .bashrc .profile .troll_5074624024543078 HELP workshop |
| Excellent, now find the troll in your command history. | history | grep troll | 1 echo troll_9394554126440791 3 cat troll_19315479765589239 4 rm troll_19315479765589239 7 history |
| Find the troll in your environment variables. | env | grep troll | z_TROLL=troll_20249649541603754 |
| Next, head into the workshop. | cd workshop/ | elf@3f417fd4a689:~/workshop$ |
| A troll is hiding in one of the workshop toolboxes. Use "grep" while ignoring case to find which toolbox the troll is in. | grep -i troll * | grep: electrical: Is a directory toolbox_191.txt:tRoLl.4056180441832623 |
| A troll is blocking the present_engine from starting. Run the present_engine binary to retrieve this troll. | ls -l present_engine chmod u+x present_engine ./present_engine |
r--r--r-- 1 elf elf 4990336 Dec 2 22:19 present_engine troll.898906189498077 |
| Trolls have blown the fuses in /home/elf/workshop/electrical. cd into electrical and rename blown_fuse0 to fuse0. | cd electrical/ mv blown_fuse0 fuse0 |
|
| Now, make a symbolic link (symlink) named fuse1 that points to fuse0 | ln -s fuse0 fuse1 | |
| Make a copy of fuse1 named fuse2. | cp fuse1 fuse2 | |
| We need to make sure trolls don't come back. Add the characters "TROLL_REPELLENT" into the file fuse2. | echo TROLL_REPELLENT >> fuse2 | |
| Find the troll somewhere in /opt/troll_den. | find /opt/troll_den -iname \*troll\* | /opt/troll_den /opt/troll_den/plugins/embeddedjsp/src/main/java/org/apache/struts2/jasper/compiler/ParserController.java /opt/troll_den/apps/showcase/src/main/resources/tRoLl.6253159819943018 /opt/troll_den/apps/rest-showcase/src/main/java/org/demo/rest/example/IndexController.java /opt/troll_den/apps/rest-showcase/src/main/java/org/demo/rest/example/OrdersController.java |
| Find the file somewhere in /opt/troll_den that is owned by the user troll. | find /opt/troll_den -user troll | /opt/troll_den/apps/showcase/src/main/resources/template/ajaxErrorContainers/tr0LL_9528909612014411 |
| Find the file created by trolls that is greater than 108 kilobytes and less than 110 kilobytes located somewhere in /opt/troll_den. | find /opt/troll_den -size +108k -size -110k | /opt/troll_den/plugins/portlet-mocks/src/test/java/org/apache/t_r_o_l_l_2579728047101724 |
| List running processes to find another troll. | ps -ef | UID PID PPID C STIME TTY TIME CMD init 1 0 0 14:24 pts/0 00:00:00 /usr/bin/python3 /usr/local/bin/tmuxp load ./mysession.yaml elf 4602 4599 1 14:31 pts/2 00:00:00 /usr/bin/python3 /14516_troll elf 4770 214 0 14:32 pts/3 00:00:00 ps -ef |
| The 14516_troll process is listening on a TCP port. Use a command to have the only listening port display to the screen. | netstat -nat | grep LISTEN | tcp 0 0 0.0.0.0:54321 0.0.0.0:* LISTEN |
| The service listening on port 54321 is an HTTP server. Interact with this server to retrieve the last troll. | curl http://127.0.0.1:54321 | troll.73180338045875 |
| Your final task is to stop the 14516_troll process to collect the remaining presents. | ps -ef | grep troll kill 4602 |
elf 4602 4599 0 14:31 pts/2 00:00:00 /usr/bin/python3 /14516_troll elf 5993 214 0 14:34 pts/3 00:00:00 grep --color=auto troll |
| Congratulations, you caught all the trolls and retrieved all the presents! |
Images⚓︎
Santa's Surf Shack and the "Linux 101" terminal
The initial terminal screen
Answer
After solving the challenge, the fact will be listed as an "Achievements" in the player's badge.
Response⚓︎
Ginger Breddie
Wow, if your surfing skills are as good as your Linux skills, you could be winning competitions!