23 levels documented
Level 0
Logging InConnect to the game server via SSH for the first time.
Solved
Level 1
Dashed FilenameRead a file named - by specifying it as an explicit path.
Solved
Level 2
Spaces in FilenameOpen a file with spaces in its name using backslash escaping.
Solved
Level 3
Hidden FilesFind a hidden file in a directory using ls -a.
Solved
Level 4
Human-Readable FileIdentify the only human-readable file among ten using a bash loop.
Solved
Level 5
Find by SizeLocate a file matching specific size and property criteria using find.
Solved
Level 6
Find Across the FilesystemTrack down a file by owner, group, and size anywhere on the server.
Solved
Level 7
Grep in a Large FileExtract a password from a multi-megabyte file using grep.
Solved
Level 8
Unique LineFind the single line that appears only once using sort and uniq.
Solved
Level 9
Binary File SearchPull a human-readable string out of a mostly binary file using grep -a.
Solved
Level 10
Base64Decode a base64-encoded file to reveal the password.
Solved
Level 11
ROT13Decode a ROT13-encoded file using tr.
Solved
Level 12
Decompression ChainReverse a hexdump and peel through multiple layers of compression.
Solved
Level 13
SSH Key AuthLog into the next level using a private SSH key instead of a password.
Solved
Level 14
NetcatRead the current password and submit it to a local port using nc.
Solved
Level 15
SSL ConnectionSubmit a password to a local SSL-encrypted port using ncat.
Solved
Level 16
Port ScanningUse nmap to identify which port in a range speaks SSL and returns a key.
Solved
Level 17
File DiffSpot the one changed line between two password files using diff.
Solved
Level 18
Bypassing .bashrcRetrieve a file using scp when the shell immediately logs you out.
Solved
Level 19
Setuid BinaryExecute commands as another user via a setuid binary.
Solved
Level 20
Two ProcessesCoordinate two concurrent processes to exchange passwords.
Solved
Level 21
Cron Job DiscoveryInspect /etc/cron.d to find a script writing the password to /tmp.
Solved
Level 22
Cron Hash AnalysisReplicate a cron script's MD5 logic to predict where it stores the password.
Solved