BUUCTF: [SWPU2019] The magical QR code

Title address: https://buuoj.cn/challenges#[SWPU2019]%E7%A5%9E%E5%A5%87%E7%9A%84%E4%BA%8C%E7%BB%B4%E7%A0 %81

binwalkAnalyze the picture and find that there is a RARcompressed package,-e直接分离

Get 4 compressed packages, three can be decompressed, only the 18494.rarpassword is required

716ADecompression of the compressed package in the folder also requires a password

First lookencode.txt

PS C:\Users\Administrator> php -r "var_dump(base64_decode('YXNkZmdoamtsMTIzNDU2Nzg5MA=='));"
string(19) "asdfghjkl1234567890"

Look atflag.doc

It's another bunch of base64, I tested it a bit, it should have been coded many times, just write the script and run

import base64

def decode(f):
	n = 0;
	while True:
		try:
			f = base64.b64decode(f)
			n += 1
		except:
			print('[+]Base64共decode了{0}次，最终解码结果如下:'.format(n))
			print(str(f,'utf-8'))
			break

if __name__ == '__main__':
	f = open('./base64.txt','r').read()
	decode(f)

PS C:\Users\Administrator\Desktop> python .\test.py
[+]Base64共decode了20次，最终解码结果如下:
comEON_YOuAreSOSoS0great

asdfghjkl1234567890Yes 看看flag在不在里面^_^.rar, the password
is actually nothing in it, it's just a simple picture, nothing steganographic...wasting my time...

comEON_YOuAreSOSoS0greatYes 18394.rar, the password is
decompressed good.mp3, it is obviously Morse code

Use Audacityopen

Thick lines are -
thin lines.

-- --- .-. ... . .. ... ...- . .-. -.-- ...- . .-. -.-- . .- ... -.--

Morse code online conversion: http://www.zhongguosou.com/zonghe/moersicodeconverter.aspx

PS: There is a pit here. It is not the first time I encountered it. I don’t understand why the last character of Morse code must 转小写be submitted correctly.

PS C:\Users\Administrator\Desktop> php -r "echo strtolower('MORSEISVERYVERYEASY');"
morseisveryveryeasy

flag{
    
    morseisveryveryeasy}