TheZeal0t's Fingerprints Are All Over This!

以下の問題文と、ファイル zealotcrypt-02.bin および zealotcrypt-02-decrypt.bin が与えられた。

This challenge description, and two files zealotcrypt-02.bin and zealotcrypt-02-decrypt.bin were given.

Calculate the SHA256 sum of TheZeal0t's cryptoware program, and its decryptor program. Enter the two hashes as the flag, separated by a pipe symbol, with the cryptoware's hash first, followed by the decryptor program's hash. Example:

flag{435524cc4113668d3f1e1e761d1717ba1bcf8b86b6dfaab9d048338e4e00a764|5d213aa47efd7e255c8304f56f148f87488a4bd9488f631ac4ed87f02c85cdce}

まず、以下のように shasum コマンドを用いて与えられた2個のファイルのSHA-256値を求めた。

Firstly, I used the shasum command to obtain the SHA-256 values of the two given files like this:

YUKI.N>shasum -a 256 zealotcrypt-02.bin zealotcrypt-02-decrypt.bin 5a54fb61f7b1a9b1b7405602388add7e3323890bc74952a62803ffb1a535338b *zealotcrypt-02.bin 969102c7feb6003624c4caf0e00fa9a60d96bc503ef0beb71ed4af68ba1fc047 *zealotcrypt-02-decrypt.bin

flag{、zealotcrypt-02.binのSHA-256値、|、zealotcrypt-02-decrypt.binのSHA-256値、} を順に繋げた以下の文字列を試したが、Incorrectとなった。

I submitted a string created by concatenating flag{, the SHA-256 value of zealotcrypt-02.bin, |, the SHA-256 value of zealotcrypt-02-decrypt.bin, and }, being judged as Incorrect.

flag{5a54fb61f7b1a9b1b7405602388add7e3323890bc74952a62803ffb1a535338b|969102c7feb6003624c4caf0e00fa9a60d96bc503ef0beb71ed4af68ba1fc047}

念の為2個のハッシュ値を入れ替えた以下の文字列も試したが、Incorrectとなった。

Then, I tried this string with the two hash values swapped just in case, being judged as Incorrect.

flag{969102c7feb6003624c4caf0e00fa9a60d96bc503ef0beb71ed4af68ba1fc047|5a54fb61f7b1a9b1b7405602388add7e3323890bc74952a62803ffb1a535338b}

SHA-256のかわりにCyberChefの SHA3 (Size: 256) を用いた以下の文字列も試したが、Incorrectとなった。

I also tried this string using SHA3 (Size: 256) on CyberChef instead of SHA-256, being judged as Incorrect.

flag{620503d3eafe3adcc2fd81989127342b793377c81930fb3d1fce9681e446379f|5a99c3fa53241f3241224e072d846a0d58274fd3d7e2bb53f3670f5fd17db30b}

その後しばらくするとこの問題は解けたことになっており、flagの特定はできなかった。

This challenge was marked as solved after a while and I couldn't determine the correct flag.

DEADFACE CTF