README.md

Level 00

Resolution

As level00 if we run ls we don't see anything at our disposal. Using the Snow Crash introduction video, we can see that there was a README.md file available to us back then in which we can read :

  FIND this first file who can run as flag00

Find being in uppercase isn't meaningless, it gives us an hint: we must use find to locate a file, more precisely, one that is owned by flag00.

  $> find / -xdev -user flag00 2>/dev/null
  /usr/sbin/john

This find command looks through everything in this filesystem to identify files that are owned by flag00 and redirect any errors (like missing permissions) to /dev/null so that our prompt isn't full of garbage

So we find one and only one file called /usr/sbin/john with some text inside it.

  $> cat /usr/sbin/john
  cdiiddwpgswtgt

Trying to connect as flag00 with this doesn't work. It doesn't look like a hashed password either. Using dcode.fr, we can give this string to the "Cipher Identifier" tool leading us to a high probability of being Caesar cipher. Then, using their Caesar cipher decoder it generates every possible password, here is the full list:

+1	bchhccvofrvsfs
+2	abggbbunequrer
+3	zaffaatmdptqdq
+4	yzeezzslcospcp
+5	xyddyyrkbnrobo
+6	wxccxxqjamqnan
+7	vwbbwwpizlpmzm
+8	uvaavvohykolyl
+9	tuzzuungxjnkxk
+10	styyttmfwimjwj
+11	rsxxsslevhlivi
+12	qrwwrrkdugkhuh
+13	pqvvqqjctfjgtg
+14	opuuppibseifsf
+15	nottoohardhere
+16	mnssnngzqcgdqd
+17	lmrrmmfypbfcpc
+18	klqqllexoaebob
+19	jkppkkdwnzdana
+20	ijoojjcvmyczmz
+21	hinniibulxbyly
+22	ghmmhhatkwaxkx
+23	fgllggzsjvzwjw
+24	efkkffyriuyviv
+25	dejjeexqhtxuhu

Everything looks like garbage except the ROT15 one being nottoohardhere. This is indeed the password for flag00. All we need to do is to use getflag now!

  $> su flag00
  Password: nottoohardhere
  $> getflag
  Check flag.Here is your token : x24ti5gi3x0ol2eh4esiuxias

So, x24ti5gi3x0ol2eh4esiuxias is the flag for this level.

Ressources

• Cipher identifier
• Caesar cipher decoder