Over The Wire - Bandit - Level 06#

Level Goal#

The password for the next level is stored in a file somewhere under the inhere directory and has all of the following properties:

human-readable
1033 bytes in size
not executable

Commands you may need to solve this level#

ls , cd , cat , file , du , find

Steps#

This time we are going to use the power of Linux and the find command. For this challenge, I recommend you to read the manual for find command, using man find, this will be very useful.

We are looking for a file that is human-readable, 1033 bytes and non-executable. For this, we will use find with some filtering parameters. But first, to play with it, we will just list all files, no need to open and enter the inhere folder:

find ./

This command will list all files in the current folder (that ./ means current folder) in a recursively way. What we need now is to filter the results to be the exact parameters we are looking for. Checking the manual for find we can find the -executable option:

-executable
              Matches files which are executable and directories which
              are searchable (in a file name resolution sense) by the
              current user.

Ok, now we can filter the results to be only the executable files, but that’s not what we are looking for, we are looking for files that are NOT executable. Returning to the manual, we can find the -not option, that inverts the result of an option:

-not expr
              Same as ! expr, but not POSIX compliant.

Making use of these options, we can list all the non-executable files inside inhere:

find ./ -not -executable

But still, there’s too many files to be searching by hand, we need to filter better. This time we will filter by size, looking for files that have exactly 1033 bytes. Checking the manual for find again, we can find the -size option:

-size n[cwbkMG]
              File uses less than, more than or exactly n units of space,
              rounding up.  The following suffixes can be used:

              `c'    for bytes

With the size option, we can add it to our command and check for the results:

find ./ -not -executable -size 1033c

With this command, the result is filtered to only one file:

./inhere/maybehere07/.file2

Reading the file with the cat command, the password for the next level is revealed.