Riddle Registry

• Description: Hi, intrepid investigator! 📄🔍 You've stumbled upon a peculiar PDF filled with what seems like nothing more than garbled nonsense. But beware! Not everything is as it appears. Amidst the chaos lies a hidden treasure-an elusive flag waiting to be uncovered.
  Find the PDF file here Hidden Confidential Document and uncover the flag within the metadata.

---

🔎 Solution

When opening the provided PDF file, I noticed that several sections were blacked out.

At first, I tried selecting all the content and pasting it into Notepad, but this didn't reveal any useful information.

Revisiting the challenge description, I found a hint pointing toward metadata. Using the exiftool command, I discovered that the Author field contained a suspicious Base64 string.

> exiftool confidential.pdf 
ExifTool Version Number         : 13.00
File Name                       : confidential.pdf
Directory                       : .
File Size                       : 183 kB
File Modification Date/Time     : 2025:10:01 03:35:25-04:00
File Access Date/Time           : 2025:10:01 03:37:24-04:00
File Inode Change Date/Time     : 2025:10:01 03:37:23-04:00
File Permissions                : -rw-------
File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.7
Linearized                      : No
Page Count                      : 1
Producer                        : PyPDF2
Author                          : cGljb0NURntwdXp6bDNkX20zdGFkYXRhX2YwdW5kIV8zNTc4NzM5YX0=  

Decoding this string revealed the flag.

> echo "cGljb0NURntwdXp6bDNkX20zdGFkYXRhX2YwdW5kIV8zNTc4NzM5YX0" | base64 -d
picoCTF{puzzl3d_m3tadata_f0und!_3578739a} 

🚩Flag

picoCTF{puzzl3d_m3tadata_f0und!_3578739a}