NACTF 2020 Write Up

Newark Academy CTF (NACTF) is an online jeopardy-style cybersecurity competition hosted by Newark Academy’s Computer Science Club. Form teams with up to 5 members and win awesome prizes! Teams compete to decrypt, hack, or reverse engineer challenges in topics like cryptography, forensics, and binary exploitation. Participation is open to anyone but prizes are restricted to US middle school and high school students. Register now to get ready for the competition to begin!

General Skills

1. Join the Discord

Flag: nactf{n1c3_j0b_h4v3_fun}

2. Intro to Flags

Flag: nactf{fl4gz_4_d4yz}

3. Basics

Base64 decode.

Flag: nactf{ba535_ar3_sw33t}

4. Hashbrowns

Decrypted the hash here.

Flag: nactf{secure_password}

Forensics

1. Meta-morphosis

Used exiftool to see the metadata.

Flag: nactf{m3ta_m3ta_m3ta_d3f4j}

2. Turnips

Hexdump shows the flag.

Flag: nactf{turn1p_f0r_h3x_f3j52}

3. Turnips 2

Fixed PNG header which still resulted in an error.

Fixed the IDHR chunk.

Flag: nactf{th3_turn1p5_ar3_tak17g_0v35_skf9}

My favorite challenge so far was Turnips 2. Fixing the PNG header to get the flag in the image was definitely a blast to learn.