NahamCon 2024 CTF!: Twine

Twine

Author: @JohnHammond#6971

Google tells me that twine means:

“strong thread or string consisting of two or more strands of hemp, cotton, or nylon twisted together.”

Solution

Step 1: Using the strings Command

The strings command scans through a binary file and prints the sequences of printable characters. It’s often used for quick analysis to find readable text in executable files or other binary data.

Step 2: Using grep to Filter the Output

The grep command searches for specific patterns within text. By combining strings with grep, you can directly search for specific keywords, such as "flag", within the output of strings.

Step 3: Executing the Command

The provided solution involves running the following command in a Unix-like terminal:

itswiz@TheWiz:/mnt/d/temp_cli/nc2024$ strings twine.jpg  | grep flag

Here’s a breakdown of the command:

• strings twine.jpg: This part scans the twine.jpg file and prints any sequences of printable characters found within it.
• |: The pipe operator takes the output of the command on its left (in this case, strings twine.jpg) and passes it as input to the command on its right (grep flag).
• grep flag: This part filters the output, searching for any lines that contain the word "flag".

Step 4: Analyzing the Output

The output of the command reveals the flag:

itswiz@TheWiz:/mnt/d/temp_cli/nc2024$ strings twine.jpg  | grep flag
flag{4ac54e3ba5f8f09049f3ad62403abb25}