/admin Administrative info about nephack.irc

12:xx -!- Join channels for flag

12:xx -!- Main Server Administrator

12:xx -!- <root@m4f1a> /list Channel Users Name

12:20 -!- #z3r0Xflag 1 [+nt]

63796e6963616c5f666c61677b77335f6c61765f72336c6179636834747d

12:20 -!- #ZEROxthisisflag 1 [+nt]

12:20 -!- #cynical 1 [+nt]

12:20 -!- #flag 1 [+nt]

12:20 -!- End of /LIST Topic for #z3r0Xflag:

63796e6963616c5f666c61677b77335f6c61765f72336c6179636834747d 0x63796e6963616c5f666c61677b77335f6c61765f72336c6179636834747d

After Decoding hex

FLAG: cynical_flag{w3_lav_r3laych4t}

5. Broken Image (200)

cynical forensic team recover a harddrive, but the image is corrupt, Ideas !!! ?

gimp -c brokenimage (gimp:21326): GLib-GObject-WARNING **: g_object_set_is_valid_property: object class ‘GeglConfig’ has no property named ‘cache-size’

GIMP-Error: Opening ‘/home/gangsta/Downloads/brokenimage’ failed: Unknown file type

What could be web images most made of ? Obviously, JPEG || PNG

cat, file, strings won’t help you here, Do hexdump

What’s that hex header ?

F ile headers are used to identify a file by examining the first 4 or 5 bytes of its

hexadecimal content.

PNG : 89 50 4E 47

Save the image and open with any Image viewer you will get the flag

Flag: cynical_flag{jp3g_is_good}

6. Hail Kim Jong-un (100)

Who loves atomic explosion?

Km6VMiTX+hcxKi96jlL3Kin6TJQmLHczToA6jlhJSIkBKkc6po13+mTB+lutQf0GKm6VMiTX+hcx+IhyQf02+41a+xHFQfT8SkcX0819MiTFLjXq+IctMicVnsgmA/CC

This is nothing, just a ATOM-128 Encoding. Use any decrypter you’ll love to use. My recommendation :

Flag: cynical_flag{n0one_\<3_at0mic_explosions} (Remove \ )

7. Wanna Die (200)

File: crypto.enc

What’s that .enc file be ? Openssl enc’d data with salted password

gangsta@heykar:~/Downloads$ file crypto.enc

crypto.enc: openssl enc’d data with salted password

Google, how to decrypt enc file from openssl, asks password while decrypting.Password is : nephack

gangsta@heykar:~$ openssl enc -help gangsta@heykar:~$ openssl enc -ciphers

Ciphers used in this file : aes-128-cbc

Block ciphers operate on a fixed length string of bits. The length of this bit string is the block size. Both the input (plaintext) and output (ciphertext) are the same length; the output cannot be shorter than the input

gangsta@heykar:~/Downloads$ openssl enc -d -aes-128-cbc -in crypto.enc -out flag.txt

enter aes-128-cbc decryption password: nephack gangsta@heykar:~/Downloads$ cat flag.txt

cynical_flag{b4d_crypt0}

8. Ditching (300)

harke got dumped by his girl, give him a suggestion : you mustn’t think more about your Ex OR one time girl she was !!!

0d1c1e050011052b07001a040205081709013e080814091e393c3e0e585815293951291a521e16

Have some read first :

In cryptography, the one-time pad (OTP) is an encryption technique that cannot be cracked, but requires the use of a one-time pre-shared key the same size as, or longer than, the message being sent.

The one-time pad was re-invented in 1917. XOR operation can be used for the encryption of a one-time pad. The XOR operation is often used to combine the plain text and the key elements, and is especially attractive on computers since it is usually a native machine instruction and is therefore very fast.

Hint

Looking at title,message and hints you could have some idea that it may be some one time pad encryption with XOR.

Crib Dragging attack can be used to crypt analyze One-Time Pad with reused key (XOR two cipher texts together).