Secret of the Polyglot

Description

The Network Operations Center (NOC) of your local institution picked up a suspicious file, they’re getting conflicting information on what type of file it is. They’ve brought you in as an external expert to examine the file. Can you extract all the information from this strange file?Download the suspicious file here.

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Steps :

open the pdf and see whats inside : it have a text saying “1n_pn9_&_pdf_2a6a1ea8}”, pn9 may be a hint for a hidden png.

after some research i looked into hex on the pdf and notice .PNG header.

00000000   89 50 4E 47  0D 0A 1A 0A  00 00 00 0D  49 48 44 52  00 00 00 32  00 00 00 32  08 06 00 00  00 1E 3F 88  B1 00 00 01  85 69 43 43  50 49 43 43  .PNG........IHDR...2...2......?......iCCPICC

tried to convert .pdf into “.png”, and yeahhhhh. here is the flag.png, putting the all parts together :

FLAG : picoCTF{f1u3n7_1n_pn9_&_pdf_2a6a1ea8}