Tab, Tab, Attack

Published: April 2, 2026

Description

Using tab complete in the terminal will add years to your life, especially when dealing with long file names. Download and extract Addadshashanammu.zip.

Download Addadshashanammu.zip from the challenge page.

wget <url>/Addadshashanammu.zip

Solution

  1. Step 1Extract the archive
    Unzip the archive to reveal the top-level directory.
    unzip Addadshashanammu.zip
    Learn more

    unzip extracts ZIP archives on Linux and macOS. ZIP is the most common archive format for cross-platform file distribution. Unlike tar.gz (which requires two tools -- tar to pack and gzip to compress), ZIP handles both archiving and compression in a single format.

    Before extracting an unknown archive, it's good practice to inspect its contents with unzip -l Addadshashanammu.zip. This lists all files inside without extracting them, preventing "zip bombs" (maliciously crafted archives that expand to enormous sizes) and showing you the directory structure ahead of time.

  2. Step 2Navigate using tab completion
    The zip contains 7 levels of nested directories with nearly identical long names. Type the first few letters of each directory name, then press Tab to autocomplete. Keep pressing Tab and Enter to descend until you reach the binary at the deepest level.
    cd Addadshashanammu/
    Learn more

    Tab completion is one of the most productivity-enhancing features of the bash and zsh shells. When you press Tab, the shell attempts to complete the current word based on available files, directories, commands, and (with plugins) command arguments. If there's a unique match, it completes immediately. If there are multiple matches, pressing Tab twice lists all options.

    This challenge deliberately names the nested directories with nearly identical long strings (inspired by a Futurama reference -- "Addadshashanammu" is from the show) to make manual typing impractical. With tab completion, you only need to type enough characters to uniquely identify each directory, then press Tab. The shell handles the rest.

    Alternative approaches for navigating deeply nested structures:

    • find . -type f -executable -- find all executable files recursively, jumping straight to the binary
    • find . -name "fang*" -- search by filename pattern
    • ls -R | grep -v "^$" -- recursive listing to see all files at once

    Tab completion also works for commands, not just filenames. Pressing Tab after typing the first few letters of a command completes the command name, which is useful when you can't remember the exact spelling of a tool.

  3. Step 3Execute the binary
    Once you've navigated to the deepest directory, run the binary fang-of-haynekhtnamet to print the flag.
    ./fang-of-haynekhtnamet
    Learn more

    The ./ prefix explicitly tells the shell to run the executable in the current directory. On Linux, the current directory is not included in $PATH by default (unlike Windows), so typing just fang-of-haynekhtnamet would result in "command not found." The ./ is a safety feature -- it prevents accidentally running a maliciously named file placed in a directory instead of the intended system command.

    Before running any downloaded binary, it's good practice to inspect it: file fang-of-haynekhtnamet tells you the binary format (ELF, PE, etc.) and architecture. strings fang-of-haynekhtnamet shows embedded text. In a CTF context, the challenge is designed to be safe -- but in real security work, never blindly execute unknown binaries, even in a VM.

    If the binary isn't executable, chmod +x fang-of-haynekhtnamet grants execute permission. The octal representation is chmod 755 for owner-read/write/execute + group/other-read/execute. File permissions are a fundamental Linux concept that controls who can read, write, or execute each file.

Flag

picoCTF{...}

The zip contains 7 levels of nested directories with near-identical long names -- tab completion is essential.

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