This challenge gave us a list of hashes! By search the hashes, I be moved to the hybrid-analysis.com and then a related file collection.
Show all entries (choose 50+) to list all the hashes & validate the hashes from the challenge, I found that just one hash was missing in that collection(069cf46549f856b7fc266feab68968ad1d5ec4569f6326d71e999526b721ee0c).
Try to search it in hybrid-analysis, I got a pdf file. Just inspect that report (Screenshoots)
–> got the flag: JISCTF{IOC-Search-Using-OSINT}