18 Pages Hdhub4u -

> echo "The flag is hidden in the zero‑filled stream." Again, a hint directing us toward Object 28. The flag we extracted from Object 28 matches the typical format for the platform (HTB…).

Thus the final flag for the challenge is:

$ 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).