Shell Breach

Daily Breach Challenge

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Mission Briefing

Next breach in 00:00:00

A nightly backup job at SecureArc Technologies archives admin credentials to an encrypted file. Find this week's backup key, decrypt the archive, and use what's inside to read the file in /root.

Shelluser@boosterbox:$ 0 commands

Past Breaches

SunMonTueWedThuFriSat

Pick a day to play its system. Days you've solved show your command count.

Back to game Interactive Tutorial

How to Play Shell Breach

No account required to play
A new fake system every day, shared by everyone
Daily leaderboard ranked by fewest commands
Your progress is saved automatically

Goal

Read the mission briefing, explore the filesystem, and either submit the flag or cat the file it asks for - in as few commands as possible.

Commands

The grammar is plain and whitespace-split - no pipes, flags or wildcards.

`ls [path]`	List the contents of the current or a given directory.
`cd <path>`	Change directory. Supports `..`, `~`, and relative or absolute paths.
`pwd`	Print the current directory.
`cat <file>`	Print a file's contents, or "Permission denied" if it's locked.
`whoami`	Print the current user.
`su <user> <password>`	Switch user, if the password matches.
`ssh <ip> <user> <password>`	Connect to a remote host, if the address and login both match.
`decrypt <file> <key>`	Unlock a file that needs a decryption key instead of a login.
`submit <flag>`	Submit the flag to solve the system.
`clear`	Clear the screen. Free - never sent to the server.
`history`	Show the commands you've typed this session. Also free.

A few extra commands exist just for atmosphere - they never count toward your score, so poke around freely:

`ipconfig`	Show this machine's fake network interfaces and IP address.
`hostname`	Print this machine's hostname.
`uname`	Print system information.
`date`	Print the current date and time.
`uptime`	Print how long this machine has been running.
`ps`	Print a list of running processes.
`neofetch`	Print a system summary.
`ping`	Ping this machine's own address.
`id`	Show your user and group IDs.
`sudo`	Try to run something as root. It won't go well.
`cowsay`	Get some wisdom from a cow.
`matrix`	Wake up...

Scoring

Fewest commands wins, not fastest time. An empty line, a typo, or an unrecognized command never counts against you and can be retried for free - and neither do any of the "just for fun" commands above. Every other command the engine actually attempts - even a wrong password or a guess at the wrong file - counts toward your total, whether it works or not.

A Full Walkthrough

Every day's system is different, but the shape of a solve is the same: look around, follow the clues, escalate if you need to, then finish the goal.

$ ls

notes.txt

$ cat notes.txt

Admin password is taped under the keyboard. Check /etc/motd.

$ cat /root/secret.txt

Permission denied.

$ cat /etc/motd

This week's password: Sunrise88!

$ su admin Sunrise88!

Switched to admin.

$ cat /root/secret.txt

CONFIDENTIAL - FLAG-7X2K9

$ submit FLAG-7X2K9

Correct! Breach complete in 6 commands.

What the Shell Looks Like

The whole game lives in this one dark screen - the mission briefing above it, then your commands and their output scrolling down as you type.

Shell Breach on a desktop browser, showing the mission briefing and a solved terminal session ending in a submitted flag. — Desktop

Shell Breach on a phone, showing the leaderboard rank widget above the mission briefing and terminal screen. — Phone

Strategy

ls and cat everything you can reach before trying to escalate - the clue you need is almost always sitting in a file you already have permission to read. If a file is locked, look for a password or key mentioned somewhere you've already read rather than guessing.

Replaying Past Days

The calendar below the terminal reaches back 30 days. Pick any past day to play it fresh in one sitting - there's no partial credit for stopping partway through and coming back later. If you get stuck, you can reveal that day's solution, but that marks it as given up rather than solved and keeps it off that day's leaderboard.

Challenge

Signed-in players can challenge each other. Pick an opponent, line up 1 to 5 systems, and set a command limit. You can also pick each system's passwords and decrypt keys yourself - your opponent still finds them in the system's files, so it's a way to leave a message rather than make it harder. Your opponent breaches the systems in order - submitting one flag connects them to the next machine - and the command count carries across every stage.

If they clear the last system within the limit, they win. If they run out of commands first, or forfeit, you win. The same scoring rules apply: typos and the just-for-fun commands are free. Unanswered and unfinished challenges expire after 7 days of no activity.

Want to try a lineup first? Tick Just me when setting up a challenge to start a solo run with the same stages and command limit - no opponent, and it never counts as a win or loss against anyone.

Break into a new fake system every day - fewest commands wins.

How to play

About Shell Breach

Shell Breach

is a free online hacking puzzle - break into a fake computer by typing real shell-style commands, no downloads and no account required to play.

Every day, everyone gets the exact same simulated system - the same files, the same fake user accounts, the same hidden flag - and you explore it by typing commands like ls, cd, cat, su, ssh, decrypt and submit. The filesystem lives entirely on the server, so there's nothing to inspect in the browser's network tab - every command is a real round trip, the same as being logged into an actual box.

Scoring is by fewest commands, not speed. A typo or an unrecognized command is always free to retry, but any command the engine actually attempts counts, win or lose - so a wrong password or a dead end costs you. Solve the day's system in as few commands as possible to climb the leaderboard.

$ ls

notes.txt

$ cat notes.txt

Admin password is taped under the keyboard. Check /etc/motd.

$ su admin Sunrise88!

Switched to admin.

$ submit FLAG-7X2K9

Correct! Breach complete in 4 commands.

Four commands from a blank prompt to a solved system - reading a clue, escalating privileges, and submitting the flag.

Want to test a friend? Sign in and send a challenge: line up one to five systems, set a command limit, and even pick the passwords and decrypt keys they'll have to find. They breach the systems one after another - submitting a flag connects them to the next machine - and win only if they clear the last one before the limit runs out. Every finished challenge counts toward the challenge leaderboard, and a solo run lets you try a lineup yourself first.

Missed a day? The replay calendar reaches back 30 days, so you can play any past system in one sitting, or reveal its solution if you get stuck - a revealed day is marked honestly and never counts toward that day's leaderboard.

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