Written by Emily Leng
Writeup by Jester
It appears the only thing you know about the flag is its MD5 hash f54f10fd6e38929084d505d0c2e9c997, and that the flag is formatted in this way: [number][adjective][color][animal] without the brackets.
Luckily, you have found some lists of the words that may have been used.
Tribute to http://hsctf.com
As the title suggests, brute forcing the answer is necessary.
The easiest way to brute force a problem, of course, is writing a script. For this solution, the script will be written in python.
To encrypt a string in md5 in python, we need to first write a function that returns the encrypted string given a string. To do this in python, we can import hashlib, then write a function that looks like:
Code:
import hashlib
def MD5hash(string):
m = hashlib.md5()
m.update(string.encode('utf-8'))
return m.hexdigest()Then, we can make lists in python that contain the various strings given, then use a while loop to connect them in order such that we will inevitably get the right string, which it will print it if it is.
So, our final code looks like:
import hashlib
def MD5hash(string):
m = hashlib.md5()
m.update(string.encode('utf-8'))
return m.hexdigest()
numbers = ['1','2','3','4','5','6','7','8','9','10']
colors = ['red','orange','yellow','green','blue','purple','pink','white','black']
animals = ['cats','dog','mice','birds','fish','turtles','elephants','snakes','pigs','cows','goats']
adjectives = ['cool','smart','funny','happy','weird','strange','normal','big','small','angry']
c1 = 0
while c1 < len(numbers):
c2 = 0
while c2 < len(adjectives):
c3 = 0
while c3 < len(colors):
c4 = 0
while c4 < len(animals):
if str(MD5hash(str(numbers[c1]+adjectives[c2]+colors[c3]+animals[c4]))) == 'f54f10fd6e38929084d505d0c2e9c997':
print(numbers[c1]+adjectives[c2]+colors[c3]+animals[c4])
c4 += 1
c3 += 1
c2 += 1
c1 += 1And it prints out the flag!
5happypurpleturtles