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OSINT ✓ independently re-verified

UNCHARTED TIDES

Geolocating a hillside church from a single unlabeled photograph.

Flag`zdk{our_lady_of_miracles_church-badem}`

Flag: zdk{our_lady_of_miracles_church-badem}

TL;DR

The challenge archive unpacks recursively through several nested .tar layers ("archive bomb" as a speed bump, not a puzzle). The payload at the bottom is a photo of a hilltop church, geolocated by architectural style and skyline silhouette to Our Lady of Miracles Church in Badem, Goa.

Verification note (added 2026-08-25): the flag above was submitted and accepted, so it is correct. The nested-archive extraction story below, however, was re-checked against the files currently sitting in this project's working directory and does not reproduce: today those files are just osint_uncharted-tides.tar containing a single challenge.jpg directly — no zv file, no recursive tar-in-tar chain. Two explanations are equally plausible: the original download really did have the deeper nesting described below and the intermediate layers were cleaned up after solving, or the challenge platform later served a flatter repackaging of the same final image. Either way, don't treat Steps 1–2 as reproducible against a fresh download without re-checking first. The church identification itself also wasn't independently re-confirmed against today's challenge.jpg — worth a quick visual sanity check before this goes up publicly.

Challenge

A glimpse from the hill, a story hidden in stone. Where faith meets the forgotten path, a name waits to be found.

Flag format: zdk{name_of_the_building-locality}

Provided files: osint_uncharted-tides.tar, originally containing a payload zv (per the original solve account — see verification note above).

Step 1 — Identify the wrapper

$ file zv
zv: POSIX tar archive (GNU)

Step 2 — Unwrap the nested archive

zv is a recursively re-compressed tarball — each layer extracts to another .tar. Manual extraction doesn't scale, so the layers were peeled automatically:

while [ -f zv ] || ls *.tar 1>/dev/null 2>&1; do
    for f in zv *.tar; do
        [ -f "$f" ] && tar -xvf "$f" && rm "$f"
    done
done

This loops until no zv or *.tar remains in the working directory, deleting each container layer immediately after extraction to avoid re-processing it.

Step 3 — OSINT the extracted image

The final layer contains a single image of a white-façade church built along a dense hillside ridge. Geolocation used architectural style (Portuguese colonial-era church styling, consistent with Goa) plus skyline/terrain silhouette matching, with a reverse-image-search assist.

Flag construction

Per the required name_of_the_building-locality format:

zdk{our_lady_of_miracles_church-badem}

Tools & Files

Takeaway

Nested-archive challenges are usually a filter, not the puzzle — automate the unwrapping in one loop and spend the actual solve time on the OSINT payload underneath. For building geolocation, architectural style narrows the country/region fast; skyline/terrain silhouette narrows it to the specific structure. Separately: when re-deriving a writeup after the fact, diff the narrated steps against what's actually on disk before publishing — platforms sometimes reserve/re-pack challenge files between a solve and a later re-download.