$ pdf-parser -dump 18pages.pdf > pdf_objects.txt The dump revealed the following interesting points:
Thus the final flag for the challenge is: 18 Pages Hdhub4u
$ pdfinfo 18pages.pdf Title: 18 Pages Creator: LaTeX with hyperref Producer: pdfTeX-1.40.21 CreationDate: D:20260312123456-04'00' ModDate: D:20260312123500-04'00' Tagged: no Pages: 18 Encrypted: no Page size: 595.276 x 841.89 pts (A4) The file looks like an ordinary PDF with (as the title hints). $ pdf-parser -dump 18pages